Contents

This
chapter
contains
the
following
sections




Section
Title

Page




“Introduction?



1-1





“Problems
Being
Addressed?



1-3





“Problems
Not
Being
Addressed?



1-5





“Design
Rationale?



1-5





“Conformance
to
the
DAIS?



1-7








The
purpose
of
the
DAIS
Application
Program
Interface

API

is
to
support
efficient
real
time
transfer
of
large
amounts
of
data
from
an
industrial
process
to
a
wide
range
of
clients

It
supports
discovery
of
parameters
and
update
of
parameter
values

The
DAIS
is
intended
for
on-line
data
transfer
and
cannot
be
used
to
configure
servers
implementing
the
API


Control
systems
used
to
monitor
and
control
industrial
processes
consist
of
the
following
major
pieces




•	
Process
instrumentation
making
sensor
data
and
actuation
capabilities
available




•	
Process
stations
or
remote
terminal
units

RTUs

reading
sensor
data
and
controlling
actuators




•	
Supervisory
Control
and
Data
Acquisition

SCADA

system
making
processed
sensor
data
and
control
capabilities
available
to
operators

applications

or
other
systems




•	
Management
systems
using
SCADA
data
to
make
further
processing
and
control




SCADA
and
management
systems
can
be
regarded
having
a
server
part
where
data
processing
is
performed
and
a
Human
Machine
Interface

HMI

part
where
visualization
and
command
dialogs
are
made

The
SCADA
and
management
system
may
have
common
or
different
HMI


This
results
in
a
hierarchical
structure
shown
below




SCADA
Management
system
Instrumentation
RTU

Process
station
Server
Server
HMI
HMI
Data
transfer
for
APIs
concerned
with
Process
data
Data
written
to
process

Figure
1-1
Control
system
structure


The
solid
arrows
in
Figure
1-1
correspond
to
transfer
of
data
from
servers
to
clients

The

data
can
be
state
variables
and
parameters

for
example

measured
values

calculated
values

limit
values

dead
bands

scan
rates

engineering
units



The
dashed
arrows
correspond
to
data
written
to
servers
by
clients

The
data
can
be
control
variables
and
parameters

The
API
support
simple
writes
operations

More
complex
controls
like
select
and
execute

for
example

breaker
on
off

or
raise
lower
commands
can
be
implemented
combining
multiple
write
and
read
operations


As
indicated
in

Figure
1-1
the
DAIS
API
can
be
used
at
several
levels
in
a
system

For

example

a
DAIS
server
can
be
an
RTU
Process
station
communication
unit

a
SCADA
server

or
even
a
Management
system


DAIS
support
both
subscription
and
read
write
operations

A
subscription
means
server
has
no
a
priori
knowledge
of
clients
and
it
is
clients
that
establish
connection
with
servers

Once
connection
is
established
a
server
calls
the
clients
back
when
data
becomes
available
or
updated

The
callbacks
mean
the
DAIS
API
also
defines
an
interface
that
the
client
has
to
implement




Server
Client
Establish
connection
Callback

data
transfer

Figure
1-2
Data
subscription


Figure
1-2
shows
the
bi-directional
subscription
with
connection
establishment
and

callback
interfaces


For
historical
reasons
SCADA
systems
for
different
industrial
processes
has
evolved
along
different
lines

SCADA
for
power
systems
has
evolved
onto
a
UNIX
base
and
SCADA
for
most
other
industrial
processes
has
evolved
onto
a
Windows
NT
base

For
UNIX
based
systems
APIs
formulated
in
CORBA

Common
Object
Request
Broker
Architecture

IDL

Interface
Definition
Language

are
now
emerging

for
example

DAIS
RFP
[1]
and
UMS
DAF
[2]


For
Windows
NT
based
systems

such
as
OLE
for
Process
Control

OPC

[3]

has
become
the
dominating
standard

OPC
defines
three
different
APIs

measurement
data
access
[4]

alarms
&
events
[5]

and
history
[6]

OPC
is
based
on
Microsoft
COM


OPC
is
focused
on
the
interfaces
and
does
not
explicitly
describe
the
information
model
behind
the
interface

The
information
model
is
however
implicit
and
can
be
derived
from
the
OPC
specifications

This
specification
describes
both
the
API
and
information
model
expressed
in
UML


Within
the
CCAPI
project
an
information
model
Common
Information
Model

CIM

[7]
has
been
developed

This
model
is
now
evolving
into
the
IEC
61970-30x
draft
standard
[8]

The
CIM
contains
a
SCADA
information
model

61970-303

with
its
roots
in
power
transmission
and
generation

The
DAIS
API
supports
the
CIM









The
DAIS
API
is
intended
for
transfer
of
process
data
on
subscription
basis
as
indicated

in
Figure
1-1
and
Figure
1-2

Process
data
consists
of
quality
tagged
and
time
stamped

scalar
values

The
API
is
intended
to
efficiently
transfer
large
amounts
of
data
simultaneously
to
many
clients

subscribers


Clients
and
servers
involved
in
data
exchange
can
be
of
many
kinds

for
example

HMI
or
management
systems
as
indicated
in

Figure
1-1


A
client
may
also
appear
as
a
server

for
example

aggregating
data
from

other
servers
or
performing
calculations
as
indicated
in
Figure
1-3


This
creates

hierarchical
structures
of
DAIS
servers




Serv
er
Server
Server
Serv
er
Serv
er
Serv
er
Server
Clien
t
DA
IS
D
A
IS
D
A
IS

Figure
1-3
Using
DAIS
as
interface
between
multiple
servers


As
an
example
the
servers
in
the
leftmost
layer
in
Figure
1-3
might
be
OPC
compliant

RTUs

or
IEDs


next
right
might
be
communication
front
ends

and
the
rightmost
server
may
provide
both
telemetered
and
estimated
data


The
DAIS
API
is
intended
to
be
used
for
a
wide
range
of
industrial
processes

For
example




•

power
transmission



•

power
generation



•

power
distribution



•

water
and
sewage
management•
oil
and
gas


•

district
heating



•

pulp
and
paper




•

food
manufacturing


The
kinds
of
data
that
can
be
reached
through
the
DAIS
API
are




•

measurement
data
access



•

alarms
&
events
access



This
data
is
typically
available
from
hardware
units
in
the
process

for
example

RTUs

PLCs

distributed
controllers

or
other
control
centers

for
example

SCADA
systems


Refined
or
calculated
data

parameters

and
alarms
&
events
might
also
come
from
applications

for
example

custom
calculations

state
estimation

optimization

in
SCADA
or
Management
systems

These
data
might
be
provided
through
the
DAIS
API
as
well







This
specification
provides
interfaces
for
data
access
including




•

Discovery
of
data
available
in
a
server




•	
Discovery
of
the
information
model
supported
by
a
server

for
example

available
types
and
their
properties





•	
Synchronous
and
asynchronous
read
or
write
of
server
data




•	
Creation
and
maintenance
of
subscriptions
at
the
server




•	
Client
side
subscription
callback
interfaces
for
event
driven
data
transfer












There
are
no
explicit
means
to
synchronize
clients

Time
stamping
of
data
is
provided
so
that
clients
can
judge
the
age










Data
is
hierarchically
organized
in
trees
of
nodes
and
items
where
the
items
are
the
leafs

The
nodes
in
the
hierarchy
have
a
type

for
example

substation

pump

breaker

or
any
collection
of
items


The
type
is
transparent
to
the
interface

An
item
is
an
instance
of
a
property
belonging
to
a
type

Properties
can
describe
any
kind
of
state
variables

control
variables

or
parameters
existing
in
a
control
system


Data
transferred
by
reads
or
callbacks
are
time
stamped
and
quality
coded












The
problem
of
configuring
a
server
or
control
system
with
nodes

items

areas

sources

reasons

condition
spaces

and
source
conditions
is
outside
the
scope
of
this
specification


The
problem
of
supervising
the
control
system
equipment

for
example

communication
lines

computers

hard
disks

and
provide
specific
interfaces
for
this
is
outside
the
scope
of
this
specification

It
is
however
possible
for
a
DAIS
server
to
provide
control
system
statuses
as
measurements









Besides
meeting
the
requirements
spelled
out
in
the
RFP
there
are
a
number
of
design
goals
that
have
shaped
solutions







OPC
has
been
in
use
for
a
number
of
years
and
this
specification
leverages
on
the
experience
gained
by
OPC

There
are
a
large
number
of
OPC
based
products
in
the
market
place
and
cases
where
DAIS
and
OPC
will
be
bridged
are
likely

Adherence
to
OPC
is
important
to
facilitate
simple
bridging
and
porting
DAIS
software
to
from
OPC










Some
design
principles
used
when
creating
OPC
were




•	
Method
behavior
is
sometimes
controlled
by
an
input
parameter




•	
Related
data
is
transferred
in
multiple
parallel
vectors





•	
Outputs
are
always
returned
in
one
or
more
output
parameters



To
simplify
and
get
a
more
uniform
interface
these
principles
have
been
replaced
by
the
following




•	
A
method
has
one
single
behavior
resulting
in
some
OPC
methods
being
replaced
by
more
than
one
DAIS
method




•	
Related
data
is
kept
together
in
structs
resulting
in
reduction
of
the
number
of
parameters
compared
to
OPC




•	
Outputs
are
returned
as
method
return
results
resulting
in
the
OPC
HRESULT
parameter
being
replaced
by
exceptions
and
reduced
number
of
output
parameters
compared
to
OPC












A
DAIS
server
is
a
real-time
system
required
to
deliver
data
in
high
rates
and
volumes

The
performance
requirements
mean
that
a
typical
DAIS
server
does
not
use
a
relational
database
management
system
for
on-line
operation
but
some
kind
of
real-time
database

The
DAIS
API
efficiently
encapsulates
such
real-time
databases
from
clients


To
be
effectively
delivering
data
DAIS
must
not
introduce
performance
bottlenecks
of
its
own

This
has
influenced
the
design
in
several
ways

listed
below








The
subscription
mechanism
consists
of
two
phases

In
the
first
the
client
negotiates
with
the
server
on
what
data
items
to
subscribe
for
and
in
the
second
the
actual
data
transfer
takes
place

This
minimizes
the
amount
of
transferred
data
between
the
server
and
the
client
during
on-line
operation










DAIS
support
to
use
sequences
of
data
in
calls
rather
than
having
calls
requiring
single
valued
parameters

This
allows
clients
to
ask
for
processing
of
multiple
data
in
a
single
call
rather
than
making
multiple
calls
thus
reducing
the
number
of
LAN
round
trips










Large
volumes
of
data
are
not
efficiently
transferred
in
one
method
call

For
this
reason
many
methods
return
an
iterator
that
is
used
to
transfer
optimal
volumes
of
data
in
each
call










The
basic
unit
of
data
is
a
union
type

SimpleValue

SimpleValue
exploits
our
knowledge
of
the
basic
data
types
needed
and
eliminates
CORBA
any
from
the
highest
bandwidth
part
of
the
interface

This
can
make
a
significant
impact
on
performance
when
accumulated
across
large
amounts
of
data














The
DAIS
has
three
major
conformance
points




1


The
DAIS
Server



2


The
DAIS
Data
Access



3


The
DAIS
Alarms
and
Events




An
implementation



•

shall
conform
to
point
1




•

shall
conform
to
either
point
2
or
point
3




•

may
conform
to
both
point
2
and
point
3









The
DAIS
interface
as
defined
in

Section
3
2

“Server
?
on
page
3-30
is
a
mandatory

conformance
point
for
a
DAIS
Server
with
the
exception
of
the
following
optional
methods




•

DAIS

Server

find
views





•

DAIS

Server

create
data
access
session
for
view





•

DAIS

Server

create
alarms
and
events
session
for
view






•

DAIS

Server

inspect




A
server
shall
also
conform
to



•


Section
3
1
1

“Character
Encoding
?
on
page
3-1






The
use
of
XPath
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?

on
page
3-25

Section
5
2
4
2

“IDL
?
on
page
5-14

and
Section
5
2
7
3

“Condition

Logic
?
on
page
5-38
is
an
optional
conformance
point












The
DAIS
interface
as
defined
in
Section
3
1

“Common
Declarations
?
on
page
3-1
and

Section
4
2

“API
?
on
page
4-8
is
a
mandatory
conformance
point
for
Data
Access












The
DAIS
interface
as
defined
in
Section
3
1

“Common
Declarations
?
on
page
3-1
and

Section
5
2

“API
?
on
page
5-6
is
a
mandatory
conformance
point
for
Alarms
and

Events














The
purpose
of
the
DAIS
Application
Program
Interface

API

is
to
support
efficient
real
time
transfer
of
large
amounts
of
data
from
an
industrial
process
to
a
wide
range
of
clients

It
supports
discovery
of
parameters
and
update
of
parameter
values

The
DAIS
is
intended
for
on-line
data
transfer
and
cannot
be
used
to
configure
servers
implementing
the
API


Control
systems
used
to
monitor
and
control
industrial
processes
consist
of
the
following
major
pieces




•	
Process
instrumentation
making
sensor
data
and
actuation
capabilities
available




•	
Process
stations
or
remote
terminal
units

RTUs

reading
sensor
data
and
controlling
actuators




•	
Supervisory
Control
and
Data
Acquisition

SCADA

system
making
processed
sensor
data
and
control
capabilities
available
to
operators

applications

or
other
systems




•	
Management
systems
using
SCADA
data
to
make
further
processing
and
control




SCADA
and
management
systems
can
be
regarded
having
a
server
part
where
data
processing
is
performed
and
a
Human
Machine
Interface

HMI

part
where
visualization
and
command
dialogs
are
made

The
SCADA
and
management
system
may
have
common
or
different
HMI


This
results
in
a
hierarchical
structure
shown
below




SCADA
Management
system
Instrumentation
RTU

Process
station
Server
Server
HMI
HMI
Data
transfer
for
APIs
concerned
with
Process
data
Data
written
to
process

Figure
1-1
Control
system
structure


The
solid
arrows
in
Figure
1-1
correspond
to
transfer
of
data
from
servers
to
clients

The

data
can
be
state
variables
and
parameters

for
example

measured
values

calculated
values

limit
values

dead
bands

scan
rates

engineering
units



The
dashed
arrows
correspond
to
data
written
to
servers
by
clients

The
data
can
be
control
variables
and
parameters

The
API
support
simple
writes
operations

More
complex
controls
like
select
and
execute

for
example

breaker
on
off

or
raise
lower
commands
can
be
implemented
combining
multiple
write
and
read
operations


As
indicated
in

Figure
1-1
the
DAIS
API
can
be
used
at
several
levels
in
a
system

For

example

a
DAIS
server
can
be
an
RTU
Process
station
communication
unit

a
SCADA
server

or
even
a
Management
system


DAIS
support
both
subscription
and
read
write
operations

A
subscription
means
server
has
no
a
priori
knowledge
of
clients
and
it
is
clients
that
establish
connection
with
servers

Once
connection
is
established
a
server
calls
the
clients
back
when
data
becomes
available
or
updated

The
callbacks
mean
the
DAIS
API
also
defines
an
interface
that
the
client
has
to
implement




Server
Client
Establish
connection
Callback

data
transfer

Figure
1-2
Data
subscription


Figure
1-2
shows
the
bi-directional
subscription
with
connection
establishment
and

callback
interfaces


For
historical
reasons
SCADA
systems
for
different
industrial
processes
has
evolved
along
different
lines

SCADA
for
power
systems
has
evolved
onto
a
UNIX
base
and
SCADA
for
most
other
industrial
processes
has
evolved
onto
a
Windows
NT
base

For
UNIX
based
systems
APIs
formulated
in
CORBA

Common
Object
Request
Broker
Architecture

IDL

Interface
Definition
Language

are
now
emerging

for
example

DAIS
RFP
[1]
and
UMS
DAF
[2]


For
Windows
NT
based
systems

such
as
OLE
for
Process
Control

OPC

[3]

has
become
the
dominating
standard

OPC
defines
three
different
APIs

measurement
data
access
[4]

alarms
&
events
[5]

and
history
[6]

OPC
is
based
on
Microsoft
COM


OPC
is
focused
on
the
interfaces
and
does
not
explicitly
describe
the
information
model
behind
the
interface

The
information
model
is
however
implicit
and
can
be
derived
from
the
OPC
specifications

This
specification
describes
both
the
API
and
information
model
expressed
in
UML


Within
the
CCAPI
project
an
information
model
Common
Information
Model

CIM

[7]
has
been
developed

This
model
is
now
evolving
into
the
IEC
61970-30x
draft
standard
[8]

The
CIM
contains
a
SCADA
information
model

61970-303

with
its
roots
in
power
transmission
and
generation

The
DAIS
API
supports
the
CIM








The
DAIS
API
is
intended
for
transfer
of
process
data
on
subscription
basis
as
indicated

in
Figure
1-1
and
Figure
1-2

Process
data
consists
of
quality
tagged
and
time
stamped

scalar
values

The
API
is
intended
to
efficiently
transfer
large
amounts
of
data
simultaneously
to
many
clients

subscribers


Clients
and
servers
involved
in
data
exchange
can
be
of
many
kinds

for
example

HMI
or
management
systems
as
indicated
in

Figure
1-1


A
client
may
also
appear
as
a
server

for
example

aggregating
data
from

other
servers
or
performing
calculations
as
indicated
in
Figure
1-3


This
creates

hierarchical
structures
of
DAIS
servers




Serv
er
Server
Server
Serv
er
Serv
er
Serv
er
Server
Clien
t
DA
IS
D
A
IS
D
A
IS

Figure
1-3
Using
DAIS
as
interface
between
multiple
servers


As
an
example
the
servers
in
the
leftmost
layer
in
Figure
1-3
might
be
OPC
compliant

RTUs

or
IEDs


next
right
might
be
communication
front
ends

and
the
rightmost
server
may
provide
both
telemetered
and
estimated
data


The
DAIS
API
is
intended
to
be
used
for
a
wide
range
of
industrial
processes

For
example




•

power
transmission



•

power
generation



•

power
distribution



•

water
and
sewage
management•
oil
and
gas


•

district
heating



•

pulp
and
paper




•

food
manufacturing


The
kinds
of
data
that
can
be
reached
through
the
DAIS
API
are




•

measurement
data
access



•

alarms
&
events
access



This
data
is
typically
available
from
hardware
units
in
the
process

for
example

RTUs

PLCs

distributed
controllers

or
other
control
centers

for
example

SCADA
systems


Refined
or
calculated
data

parameters

and
alarms
&
events
might
also
come
from
applications

for
example

custom
calculations

state
estimation

optimization

in
SCADA
or
Management
systems

These
data
might
be
provided
through
the
DAIS
API
as
well







This
specification
provides
interfaces
for
data
access
including




•

Discovery
of
data
available
in
a
server




•	
Discovery
of
the
information
model
supported
by
a
server

for
example

available
types
and
their
properties





•	
Synchronous
and
asynchronous
read
or
write
of
server
data




•	
Creation
and
maintenance
of
subscriptions
at
the
server




•	
Client
side
subscription
callback
interfaces
for
event
driven
data
transfer












There
are
no
explicit
means
to
synchronize
clients

Time
stamping
of
data
is
provided
so
that
clients
can
judge
the
age










Data
is
hierarchically
organized
in
trees
of
nodes
and
items
where
the
items
are
the
leafs

The
nodes
in
the
hierarchy
have
a
type

for
example

substation

pump

breaker

or
any
collection
of
items


The
type
is
transparent
to
the
interface

An
item
is
an
instance
of
a
property
belonging
to
a
type

Properties
can
describe
any
kind
of
state
variables

control
variables

or
parameters
existing
in
a
control
system


Data
transferred
by
reads
or
callbacks
are
time
stamped
and
quality
coded












This
specification
provides
interfaces
for
data
access
including




•

Discovery
of
data
available
in
a
server




•	
Discovery
of
the
information
model
supported
by
a
server

for
example

available
types
and
their
properties





•	
Synchronous
and
asynchronous
read
or
write
of
server
data




•	
Creation
and
maintenance
of
subscriptions
at
the
server




•	
Client
side
subscription
callback
interfaces
for
event
driven
data
transfer











There
are
no
explicit
means
to
synchronize
clients

Time
stamping
of
data
is
provided
so
that
clients
can
judge
the
age









Data
is
hierarchically
organized
in
trees
of
nodes
and
items
where
the
items
are
the
leafs

The
nodes
in
the
hierarchy
have
a
type

for
example

substation

pump

breaker

or
any
collection
of
items


The
type
is
transparent
to
the
interface

An
item
is
an
instance
of
a
property
belonging
to
a
type

Properties
can
describe
any
kind
of
state
variables

control
variables

or
parameters
existing
in
a
control
system


Data
transferred
by
reads
or
callbacks
are
time
stamped
and
quality
coded










The
problem
of
configuring
a
server
or
control
system
with
nodes

items

areas

sources

reasons

condition
spaces

and
source
conditions
is
outside
the
scope
of
this
specification


The
problem
of
supervising
the
control
system
equipment

for
example

communication
lines

computers

hard
disks

and
provide
specific
interfaces
for
this
is
outside
the
scope
of
this
specification

It
is
however
possible
for
a
DAIS
server
to
provide
control
system
statuses
as
measurements








Besides
meeting
the
requirements
spelled
out
in
the
RFP
there
are
a
number
of
design
goals
that
have
shaped
solutions







OPC
has
been
in
use
for
a
number
of
years
and
this
specification
leverages
on
the
experience
gained
by
OPC

There
are
a
large
number
of
OPC
based
products
in
the
market
place
and
cases
where
DAIS
and
OPC
will
be
bridged
are
likely

Adherence
to
OPC
is
important
to
facilitate
simple
bridging
and
porting
DAIS
software
to
from
OPC










Some
design
principles
used
when
creating
OPC
were




•	
Method
behavior
is
sometimes
controlled
by
an
input
parameter




•	
Related
data
is
transferred
in
multiple
parallel
vectors





•	
Outputs
are
always
returned
in
one
or
more
output
parameters



To
simplify
and
get
a
more
uniform
interface
these
principles
have
been
replaced
by
the
following




•	
A
method
has
one
single
behavior
resulting
in
some
OPC
methods
being
replaced
by
more
than
one
DAIS
method




•	
Related
data
is
kept
together
in
structs
resulting
in
reduction
of
the
number
of
parameters
compared
to
OPC




•	
Outputs
are
returned
as
method
return
results
resulting
in
the
OPC
HRESULT
parameter
being
replaced
by
exceptions
and
reduced
number
of
output
parameters
compared
to
OPC












A
DAIS
server
is
a
real-time
system
required
to
deliver
data
in
high
rates
and
volumes

The
performance
requirements
mean
that
a
typical
DAIS
server
does
not
use
a
relational
database
management
system
for
on-line
operation
but
some
kind
of
real-time
database

The
DAIS
API
efficiently
encapsulates
such
real-time
databases
from
clients


To
be
effectively
delivering
data
DAIS
must
not
introduce
performance
bottlenecks
of
its
own

This
has
influenced
the
design
in
several
ways

listed
below








The
subscription
mechanism
consists
of
two
phases

In
the
first
the
client
negotiates
with
the
server
on
what
data
items
to
subscribe
for
and
in
the
second
the
actual
data
transfer
takes
place

This
minimizes
the
amount
of
transferred
data
between
the
server
and
the
client
during
on-line
operation










DAIS
support
to
use
sequences
of
data
in
calls
rather
than
having
calls
requiring
single
valued
parameters

This
allows
clients
to
ask
for
processing
of
multiple
data
in
a
single
call
rather
than
making
multiple
calls
thus
reducing
the
number
of
LAN
round
trips










Large
volumes
of
data
are
not
efficiently
transferred
in
one
method
call

For
this
reason
many
methods
return
an
iterator
that
is
used
to
transfer
optimal
volumes
of
data
in
each
call










The
basic
unit
of
data
is
a
union
type

SimpleValue

SimpleValue
exploits
our
knowledge
of
the
basic
data
types
needed
and
eliminates
CORBA
any
from
the
highest
bandwidth
part
of
the
interface

This
can
make
a
significant
impact
on
performance
when
accumulated
across
large
amounts
of
data














OPC
has
been
in
use
for
a
number
of
years
and
this
specification
leverages
on
the
experience
gained
by
OPC

There
are
a
large
number
of
OPC
based
products
in
the
market
place
and
cases
where
DAIS
and
OPC
will
be
bridged
are
likely

Adherence
to
OPC
is
important
to
facilitate
simple
bridging
and
porting
DAIS
software
to
from
OPC









Some
design
principles
used
when
creating
OPC
were




•	
Method
behavior
is
sometimes
controlled
by
an
input
parameter




•	
Related
data
is
transferred
in
multiple
parallel
vectors





•	
Outputs
are
always
returned
in
one
or
more
output
parameters



To
simplify
and
get
a
more
uniform
interface
these
principles
have
been
replaced
by
the
following




•	
A
method
has
one
single
behavior
resulting
in
some
OPC
methods
being
replaced
by
more
than
one
DAIS
method




•	
Related
data
is
kept
together
in
structs
resulting
in
reduction
of
the
number
of
parameters
compared
to
OPC




•	
Outputs
are
returned
as
method
return
results
resulting
in
the
OPC
HRESULT
parameter
being
replaced
by
exceptions
and
reduced
number
of
output
parameters
compared
to
OPC











A
DAIS
server
is
a
real-time
system
required
to
deliver
data
in
high
rates
and
volumes

The
performance
requirements
mean
that
a
typical
DAIS
server
does
not
use
a
relational
database
management
system
for
on-line
operation
but
some
kind
of
real-time
database

The
DAIS
API
efficiently
encapsulates
such
real-time
databases
from
clients


To
be
effectively
delivering
data
DAIS
must
not
introduce
performance
bottlenecks
of
its
own

This
has
influenced
the
design
in
several
ways

listed
below







The
subscription
mechanism
consists
of
two
phases

In
the
first
the
client
negotiates
with
the
server
on
what
data
items
to
subscribe
for
and
in
the
second
the
actual
data
transfer
takes
place

This
minimizes
the
amount
of
transferred
data
between
the
server
and
the
client
during
on-line
operation









DAIS
support
to
use
sequences
of
data
in
calls
rather
than
having
calls
requiring
single
valued
parameters

This
allows
clients
to
ask
for
processing
of
multiple
data
in
a
single
call
rather
than
making
multiple
calls
thus
reducing
the
number
of
LAN
round
trips









Large
volumes
of
data
are
not
efficiently
transferred
in
one
method
call

For
this
reason
many
methods
return
an
iterator
that
is
used
to
transfer
optimal
volumes
of
data
in
each
call









The
basic
unit
of
data
is
a
union
type

SimpleValue

SimpleValue
exploits
our
knowledge
of
the
basic
data
types
needed
and
eliminates
CORBA
any
from
the
highest
bandwidth
part
of
the
interface

This
can
make
a
significant
impact
on
performance
when
accumulated
across
large
amounts
of
data












The
DAIS
has
three
major
conformance
points




1


The
DAIS
Server



2


The
DAIS
Data
Access



3


The
DAIS
Alarms
and
Events




An
implementation



•

shall
conform
to
point
1




•

shall
conform
to
either
point
2
or
point
3




•

may
conform
to
both
point
2
and
point
3









The
DAIS
interface
as
defined
in

Section
3
2

“Server
?
on
page
3-30
is
a
mandatory

conformance
point
for
a
DAIS
Server
with
the
exception
of
the
following
optional
methods




•

DAIS

Server

find
views





•

DAIS

Server

create
data
access
session
for
view





•

DAIS

Server

create
alarms
and
events
session
for
view






•

DAIS

Server

inspect




A
server
shall
also
conform
to



•


Section
3
1
1

“Character
Encoding
?
on
page
3-1






The
use
of
XPath
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?

on
page
3-25

Section
5
2
4
2

“IDL
?
on
page
5-14

and
Section
5
2
7
3

“Condition

Logic
?
on
page
5-38
is
an
optional
conformance
point












The
DAIS
interface
as
defined
in
Section
3
1

“Common
Declarations
?
on
page
3-1
and

Section
4
2

“API
?
on
page
4-8
is
a
mandatory
conformance
point
for
Data
Access












The
DAIS
interface
as
defined
in
Section
3
1

“Common
Declarations
?
on
page
3-1
and

Section
5
2

“API
?
on
page
5-6
is
a
mandatory
conformance
point
for
Alarms
and

Events














The
DAIS
interface
as
defined
in

Section
3
2

“Server
?
on
page
3-30
is
a
mandatory

conformance
point
for
a
DAIS
Server
with
the
exception
of
the
following
optional
methods




•

DAIS

Server

find
views





•

DAIS

Server

create
data
access
session
for
view





•

DAIS

Server

create
alarms
and
events
session
for
view






•

DAIS

Server

inspect




A
server
shall
also
conform
to



•


Section
3
1
1

“Character
Encoding
?
on
page
3-1






The
use
of
XPath
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?

on
page
3-25

Section
5
2
4
2

“IDL
?
on
page
5-14

and
Section
5
2
7
3

“Condition

Logic
?
on
page
5-38
is
an
optional
conformance
point











The
DAIS
interface
as
defined
in
Section
3
1

“Common
Declarations
?
on
page
3-1
and

Section
4
2

“API
?
on
page
4-8
is
a
mandatory
conformance
point
for
Data
Access











The
DAIS
interface
as
defined
in
Section
3
1

“Common
Declarations
?
on
page
3-1
and

Section
5
2

“API
?
on
page
5-6
is
a
mandatory
conformance
point
for
Alarms
and

Events












Contents

This
chapter
contains
the
following
sections




Section
Title

Page




“OLE
for
Process
Control

OPC
?



2-1





“Data
Access
Facility

DAF
?



2-4





“COM
and
CORBA
IDL
Differences?



2-6





“IEC
1346-1

Structuring
and
Naming?



2-7





“IEC
61970
EMS
API?



2-7





“XPath?



2-8








Differences
and
similarities
between
OPC
and
DAIS
are
described
in
this
chapter







OPC
is
a
service
API
providing
access
to
data
managed
by
the
server

The
data

for
example

nodes

items

areas

sources

conditions

reasons

are
not
instantiated
as
objects
at
the
client

This
means
that
OPC
does
not
define
any
particular
APIs
for
the
data
instances
that
a
client
can
deal
with
directly

OPC
has
a
few
coarse
objects
like
OPCGroup
and
OPCEventSubscription
supporting
the
data
access

DAIS
has
adopted
this
principle
and
is
identical
to
OPC
in
this
respect


In
OPC
each
client
has
its
own
OPC
server
object

In
DAIS
there
is
only
one
DAIS
server
object
shared
by
all
clients

To
support
individual
client
sessions
a
new
session
interface
is
defined

There
is
one
interface
for
data
access
session
objects
and
one
for
alarms
&
events
session
objects

The
session
objects
correspond
to
the
OPC
server
object


The
OPC
server
object
has
interfaces
for
browsing
server
data

for
example

IOPCBrowseServerAddressSpace
and
IOPCEventAreaBrowser

and
information
model

for
example

IOPCItemProperties


In
DAIS
each
type
of
data
has
its
own
object
for
browsing

these
objects
are
called
“home?
objects

The
OPC
browse
interface
methods
are
hence
divided
among
the
different
home
objects








Many
OPC
interface

method

and
parameter
names
have
been
kept
but
recasted
according
to
the
CORBA
style
guide

But
many
OPC
names
have
been
replaced
by
new
names
to
more
clearly
indicate
the
meaning

This
is
particularly
the
case
for
the
browse
and
alarms
&
events
APIs










In
OPC
it
is
common
to
return
arrays
of
HRESULTs
corresponding
to
arrays
of
data

In
the
case
where
the
data
did
not
contain
any
errors
an
array
with
“no
error
occurred?
codes
still
is
returned

In
DAIS
such
error
codes
will
be
returned
as
a
sequence
of
error
structs
identifying
the
erroneous
data
and
an
error
code

In
case
of
no
errors
the
sequence
of
error
structs
is
empty










OPC
data
accesses
use
both
server
and
client
side
handles
created
based
on
identification
texts
for
nodes
and
items

To
make
the
translation
from
identification
texts
to
handles
fast
and
avoid
repeated
translation
in
OPC
an
intermediate
server
side
identifier
called
the
blob
exists

In
DAIS
the
server
side
handles
and
blobs
are
replaced
by
identifiers
based
on
ResourceIDs

both
for
nodes
and
items


For
a
description
of
ResourceIDs
refer
to

Section
2
2

“Data
Access
Facility

DAF

?
on
page
2-4

The
OPC
client
side
handles
are

still
kept
in
DAIS










COM
OPC
use
the
standard
interfaces
IConnectionPoint
to
set
up
callbacks

In
DAIS
callbacks
are
set
up
directly
between
server
and
client
by
updating
an
attribute
holding
the
callback
object










The
COM
style
enumerators
in
OPC
are
replaced
by
CORBA
style
iterators
in
DAIS










In
OPC
multiple
parallel
vectors
often
pass
data

In
DAIS
a
single
vector
holding
structs

thus
reducing
the
number
of
parameters

replaces
the
parallel
vectors










In
OPC
all
methods
return
the
HRESULT
error
value

In
DAIS
HRESULTs
are
replaced
by
exceptions
and
out
parameters
are
returned
as
method
results
instead

Only
in
a
few
cases
are
there
additional
output
parameters
in
DAIS










In
OPC
data
is
generally
organized
in
hierarchical
structures

In
data
access
the
leafs
are
called
leaf
nodes
and
the
branches
branch
nodes
or
items

A
leaf
node
or
item
is
the
same
as
an
instance
of
property
at
an
object

A
branch
node
corresponds
to
an




•

Object
having
properties




•

Arbitrary
organization
of
other
branch
nodes




•

Object
having
both
properties
and
other
branch
nodes
as
children




In
DAIS
data
access
the
branch
nodes
are
called
nodes
and
the
leaf
nodes
are
called
items

In
DAIS
alarms
&
events

the
branch
nodes
are
called
areas
and
the
leaf
nodes
sources


In
OPC
branch
and
leaf
nodes
have
a
name
unique
among
the
nodes
or
items
that
are
children
of
the
same
node

A
second
name
is
formed
by
combining
these
names
from
each
branch
node
in
the
path
from
the
node
or
leaf
to
the
root

Both
names
are
called
ItemIDs
in
OPC
and
the
name
created
by
following
the
path
to
the
root
is
sometimes
called
a
fully
qualified
ItemID


In
DAIS
the
name
unique
among
the
child’s
to
the
same
node
is
called
label
and
the
name
including
the
labels
from
all
nodes
in
the
path
to
the
root
is
called
pathname

Both
DAIS
branch
nodes
and
leaf
nodes
have
both
a
label
and
a
pathname


A
label
is
used
in
the
same
way
as
a
name
but
the
word
label
is
preferred
before
the
word
name
as
it
denotes
something
that
is
atomic

that
is

it
cannot
be
further
divided










OPC
provides
a
server
side
cursor
from
where
browsing
is
made
and
the
OPC
interface
provides
methods
to
move
the
cursor


DAIS
does
not
provide
server
side
cursors
and
requires
the
client
to
keep
track
of
browse
positions
themselves

The
reason
for
removing
server
side
cursors
is
it
makes
clean
up
after
crashed
clients
easier
and
simplifies
the
server
design










OPC
does
not
support
types
meaning
it
is
not
possible
in
OPC
to
get
information
about
the
type
of
a
node

OPC
however
supports
properties

which
means
it
is
possible
to
browse
the
existing
properties
and
what
properties
a
particular
node
has

DAIS
has
extended
this
to
also
include
types

that
is

it
is
possible
to
browse
existing
types

the
properties
each
type
has
and
each
node
has
a
type


OPC
defines
the
following
property
sets




•

set
1
of
OPC
specific
properties



•

set
2
of
OPC
recommended
properties



•

set
3
of
vendor
specific
properties



In
DAIS

OPC
set
1
properties
cannot
be
browsed
through
the
property-browsing
interface

Property


Instead
access
of
set
1
properties
is
direct
in
the
interfaces
as
parameters
or
struct
members
as
is
the
case
for
OPC

This
means
that
DAIS
exposes
only
OPC
set
2
and
3
properties
through
the
property
browse
interface














The
UMS
DAF
and
DAIS
are
server
APIs
for
access
of
object
data
rather
than
the
data
objects
themselves







The
DAF
describes
a
generic
interface
for
navigating
and
reading
data
from
complex
data
structures
including
relations
between
objects

Both
DAF
and
DAIS
support
navigation
in
a
space
of
hierarchically
structured
objects

an
object
is
called
a
node
in
DAIS
and
a
resource
in
DAF


Both
support
identification
of
objects
and
properties
at
an
object

In
DAIS
an
instance
of
property
at
an
object
is
called
an
item
and
an
ItemID

item
identifier

identifies
an
item

An
ItemID
consists
of
a
ResourceID

resource
identifier

for
the
node
and
a
PropertyID

property
identifier

for
the
property

The
DAIS
API
uses
ItemIDs
to
access
data
while
the
DAF
uses
ResourceIDs
and
PropertyIDs
separated


A
system
may
implement
both
a
DAF
server
and
a
DAIS
server

In
such
a
system
it
shall
be
assumed
that
the
same
object
will
have
the
same
ResourceID
seen
through
either
API

This
means
it
shall
be
possible
to
navigate
to
an
object

retrieve
its
ResourceID
through
one
of
the
APIs

and
use
that
ResourceID
with
the
other
API

In
the
same
way
PropertyIDs
are
the
same


Textual
identification
of
resources
and
properties
in
the
DAF
is
by
URIs

Uniform
Resource
Identifier


ResourceIDs
and
PropertyIDs
have
their
own
URIs

URIs
can
be
translated
into
corresponding
ResourceIDs
and
PropertyIDs
and
vice
versa

A
property
name
is
a
URI
where
the
container
part
is
a
unique
schema
identifier
and
the
fragment
part
is
the
property
name


For
example


http


www
epri
com
schema
CIM-07f
xml#Measurement
positiveFlowIn

DAIS
does
not
support
URIs
directly
but
has
a
textual
representation
for
nodes

items

types

and
properties

This
textual
representation
may
correspond
to
the
fragment
part
of
a
URI










In
the
case
where
a
system
supports
both
the
DAF
and
the
DAIS
interfaces
it
is
expected
that
the
same
object
will
be
identified
by
the
same
ResourceID
through
both
interfaces
and
the
same
property
by
the
same
PropertyID

Sameness
of
objects
and
properties

however

depends
on
the
information
model
exposed
through
the
two
interfaces
and
if
the
information
models
are
different

then
a
mapping
is
required


In
the
case
where
a
system
supports
both
the
DAF
and
the
DAIS
interfaces
it
is
expected
that
the
same
objects
will
be
identified
by
the
same
ResourceID
and
URI
fragment
through
both
interfaces
and
the
same
property
by
the
same
PropertyID
and
URI
fragment


The
exact
mapping
has
to
be
described
for
each
DAIS
item
–
DAF
property
pair
according
to
the
underlying
information
models


Section
4
1
5

“Utility
SCADA
EMS

Measurement
Model
?
on
page
4-5
elaborates
on
the
information
model
and
a
detailed

mapping
between
IEC
61970-30x
and
the
DAIS
can
be
found
in
Section
4
1
5

“Utility

SCADA
EMS
Measurement
Model
?
on
page
4-5



The
foregoing
concepts
are
fundamental
enough
that
they
should
find
equivalents
in
any

data
repository

Some

perhaps
approximate

equivalents
are
given
in
Table
2-1
as
a

guide


Table
2-1
Mappings
between
modeling
languages



RDF

DAF

Relational
Model

UML

DAIS



Resource

Resource

ResourceID

Tuple

i
e


row


Object

Node

ResourceID



Property

Property

PropertyID

Attribute

i
e


column

or
foreign
key

Attribute
or
association

Property

PropertyID



Class

Class

ClassID

Relation

i
e


table


Class

Type

TypeID



Resource
Description

Resource
Description

Tuple
value

-
Sequence
<ItemState>



URI

URI

ResourceID

Key
value

-



Value

SimpleValue

Field
value

-
SimpleValue



-
ResourceID
and
PropertyID
pair

-
-
Item

ItemID











DAIS
uses
the
DAF
SimpleValue
type
for
data
transferred
over
the
API
instead
of
the
OPC
type
VARIANT

The
data
types
used
in
OPC
are
Microsoft
COM
types
and
as
DAIS
is
a
CORBA
API
a
mapping
of
the
data
types
is
needed

The
translation
of
OPC
COM
data
types
to
DAF
CORBA
data
types
is
listed
below


Table
2-2
Mappings
between
OPC
and
DAF
data
types



OPC
COM
basic
types

DAF
Simple
Value
types



-
ResourceID

RESOURCE
TYPE




-
URI

URI
TYPE




LPWSTR

VT
BSTR


string

STRING
TYPE




BOOL

VT
BOOL


boolean

BOOLEAN
TYPE




LONG

VT
R4


long

INT
TYPE




DWORD

VT
I4


unsigned
long

UNSIGNED
TYPE




double

VT
R8


double

DOUBLE
TYPE




-
Complex

COMPLEX
TYPE




FILETIME

VT
Date


DateTime

DATE
TIME
TYPE




-
ULongLong

ULONG
LONG
TYPE




WORD

VT
I2


unsigned
long

UNSIGNED
TYPE




FLOAT

VT
R4


double

DOUBLE
TYPE




BYTE

VT
UI1


-


HRESULT

VT
ERROR


-


VARIANT

VARTYPE


SimpleValue

SimpleValueType














Interfaces
defined
in
COM
and
CORBA
IDL
differ
in
a
number
of
ways

Important
differences
concerning
interface
definitions
are

•
object
referencing




•

interface
management




•

error
management

and



•

IDL




A
detailed
description
of
the
mapping
can
be
found
in
the
CORBA
2
3
specification

chapters
17

18

and
19







In
CORBA
each
object
is
uniquely
referenced
in
one
step

In
COM
obtaining
an
object
usually
is
a
two
step
process

In
the
first
step
a
stateless
server
object
is
obtained

In
the
second
step
the
server
object
is
loaded
with
state
data

In
CORBA
an
object
is
a
unique
individual
that
contains
state
from
the
very
beginning










A
CORBA
object
has
a
single
interface

This
interface
can
be
built
from
several
other
interfaces
through
inheritance

The
resulting
interface
might
have
many
methods
and
hence
become
big

A
COM
object
usually
has
multiple
interfaces
and
supports
the
client
to
detect
and
navigate
between
these
interfaces
at
run
time

As
a
CORBA
interface
is
defined
by
inheritance
it
has
to
be
fully
defined
at
compile
time

As
COM
allows
run
time
detection
of
interfaces

the
IUnknown

QueryInterface


method

a
full
match
between
interfaces
implemented
by
a
server
and
interfaces
known
to
a
client
is
not
required


Mapping
OPC
interfaces
to
DAIS
interfaces
can
be
done
in
two
ways




1
	
Inherit
a
number
of
OPC
interfaces
into
one
CORBA
object

This
may
result
in
name
clashes
that
require
renaming
of
methods




2
	
Instantiate
an
OPC
interface
as
an
own
CORBA
object
referenced
by
a
container
object




Both
techniques
are
used
in
the
DAIS
specification










CORBA
provides
exceptions
for
error
handling
and
COM
does
not

COM
provides
error
status
through
a
return
parameter
called
HRESULT

The
caller
has
to
explicitly
test
the
HRESULT
to
decide
if
the
operation
was
successful

HRESULT
return
parameters
are
replaced
by
CORBA
exceptions










The
COM
and
CORBA
IDL
have
several
syntactical
differences
and
use
different
style
guides












DAIS

as
well
as
OPC

structure
nodes
and
items
hierarchically

Nodes
and
items
have
a
label
uniquely
identifying
child’s
located
at
the
same
node

The
labels
from
the
nodes
in
the
path
from
a
node
or
item
to
the
root
form
a
pathname

The
pathname
uniquely
identifies
a
node
or
item
in
the
tree


The
same
principle
for
naming
objects
is
described
in
the
IEC
1346-1
standard

IEC
1346-1
call
labels
for
single
level
designation
and
the
pathname
for
multi
level
designation
and
supports
multiple
hierarchical
structures

The
DAIS
supports
multiple
structures
by
allowing
multiple
views
where
each
view
exposes
one
structure









The
IEC
61970-30x
[8]
draft
standard

also
named
CIM

describes
a
specific
organization
of
power
system
objects
in
a
hierarchical
structure

DAIS
is
transparent
to
the
structure
and
hence
supports
the
IEC
61970
structure


DAIS
is
also
transparent
to
what
attributes
are
defined
as
long
as
they
can
be
reached
through
the
hierarchy

DAIS
however
defines
a
set
of
attributes
that
a
DAIS
server
is
expected
to
support

Some
of
these
attributes
can
also
be
found
in
IEC
61970-30x

A
detailed
attribute
mapping
is
provided
later
in
this
specification
and
is
further
elaborated

in
Section
4
1
5

“Utility
SCADA
EMS
Measurement
Model
?
on
page
4-5








The
W3C
XPath
[13]
standard
describes
how
navigation
in
a
hierarchical
structure

i
e


an
XML
document

is
made
using
an
expression


In
DAIS

navigation
is
made
using
the
various
browse
APIs

However
in
one
place
there
is
a
need
to
describe
navigation
paths
as
expressions
and
that
is
for
the
condition
logic
in
Alarms
and
Events













Differences
and
similarities
between
OPC
and
DAIS
are
described
in
this
chapter







OPC
is
a
service
API
providing
access
to
data
managed
by
the
server

The
data

for
example

nodes

items

areas

sources

conditions

reasons

are
not
instantiated
as
objects
at
the
client

This
means
that
OPC
does
not
define
any
particular
APIs
for
the
data
instances
that
a
client
can
deal
with
directly

OPC
has
a
few
coarse
objects
like
OPCGroup
and
OPCEventSubscription
supporting
the
data
access

DAIS
has
adopted
this
principle
and
is
identical
to
OPC
in
this
respect


In
OPC
each
client
has
its
own
OPC
server
object

In
DAIS
there
is
only
one
DAIS
server
object
shared
by
all
clients

To
support
individual
client
sessions
a
new
session
interface
is
defined

There
is
one
interface
for
data
access
session
objects
and
one
for
alarms
&
events
session
objects

The
session
objects
correspond
to
the
OPC
server
object


The
OPC
server
object
has
interfaces
for
browsing
server
data

for
example

IOPCBrowseServerAddressSpace
and
IOPCEventAreaBrowser

and
information
model

for
example

IOPCItemProperties


In
DAIS
each
type
of
data
has
its
own
object
for
browsing

these
objects
are
called
“home?
objects

The
OPC
browse
interface
methods
are
hence
divided
among
the
different
home
objects








Many
OPC
interface

method

and
parameter
names
have
been
kept
but
recasted
according
to
the
CORBA
style
guide

But
many
OPC
names
have
been
replaced
by
new
names
to
more
clearly
indicate
the
meaning

This
is
particularly
the
case
for
the
browse
and
alarms
&
events
APIs










In
OPC
it
is
common
to
return
arrays
of
HRESULTs
corresponding
to
arrays
of
data

In
the
case
where
the
data
did
not
contain
any
errors
an
array
with
“no
error
occurred?
codes
still
is
returned

In
DAIS
such
error
codes
will
be
returned
as
a
sequence
of
error
structs
identifying
the
erroneous
data
and
an
error
code

In
case
of
no
errors
the
sequence
of
error
structs
is
empty










OPC
data
accesses
use
both
server
and
client
side
handles
created
based
on
identification
texts
for
nodes
and
items

To
make
the
translation
from
identification
texts
to
handles
fast
and
avoid
repeated
translation
in
OPC
an
intermediate
server
side
identifier
called
the
blob
exists

In
DAIS
the
server
side
handles
and
blobs
are
replaced
by
identifiers
based
on
ResourceIDs

both
for
nodes
and
items


For
a
description
of
ResourceIDs
refer
to

Section
2
2

“Data
Access
Facility

DAF

?
on
page
2-4

The
OPC
client
side
handles
are

still
kept
in
DAIS










COM
OPC
use
the
standard
interfaces
IConnectionPoint
to
set
up
callbacks

In
DAIS
callbacks
are
set
up
directly
between
server
and
client
by
updating
an
attribute
holding
the
callback
object










The
COM
style
enumerators
in
OPC
are
replaced
by
CORBA
style
iterators
in
DAIS










In
OPC
multiple
parallel
vectors
often
pass
data

In
DAIS
a
single
vector
holding
structs

thus
reducing
the
number
of
parameters

replaces
the
parallel
vectors










In
OPC
all
methods
return
the
HRESULT
error
value

In
DAIS
HRESULTs
are
replaced
by
exceptions
and
out
parameters
are
returned
as
method
results
instead

Only
in
a
few
cases
are
there
additional
output
parameters
in
DAIS










In
OPC
data
is
generally
organized
in
hierarchical
structures

In
data
access
the
leafs
are
called
leaf
nodes
and
the
branches
branch
nodes
or
items

A
leaf
node
or
item
is
the
same
as
an
instance
of
property
at
an
object

A
branch
node
corresponds
to
an




•

Object
having
properties




•

Arbitrary
organization
of
other
branch
nodes




•

Object
having
both
properties
and
other
branch
nodes
as
children




In
DAIS
data
access
the
branch
nodes
are
called
nodes
and
the
leaf
nodes
are
called
items

In
DAIS
alarms
&
events

the
branch
nodes
are
called
areas
and
the
leaf
nodes
sources


In
OPC
branch
and
leaf
nodes
have
a
name
unique
among
the
nodes
or
items
that
are
children
of
the
same
node

A
second
name
is
formed
by
combining
these
names
from
each
branch
node
in
the
path
from
the
node
or
leaf
to
the
root

Both
names
are
called
ItemIDs
in
OPC
and
the
name
created
by
following
the
path
to
the
root
is
sometimes
called
a
fully
qualified
ItemID


In
DAIS
the
name
unique
among
the
child’s
to
the
same
node
is
called
label
and
the
name
including
the
labels
from
all
nodes
in
the
path
to
the
root
is
called
pathname

Both
DAIS
branch
nodes
and
leaf
nodes
have
both
a
label
and
a
pathname


A
label
is
used
in
the
same
way
as
a
name
but
the
word
label
is
preferred
before
the
word
name
as
it
denotes
something
that
is
atomic

that
is

it
cannot
be
further
divided










OPC
provides
a
server
side
cursor
from
where
browsing
is
made
and
the
OPC
interface
provides
methods
to
move
the
cursor


DAIS
does
not
provide
server
side
cursors
and
requires
the
client
to
keep
track
of
browse
positions
themselves

The
reason
for
removing
server
side
cursors
is
it
makes
clean
up
after
crashed
clients
easier
and
simplifies
the
server
design










OPC
does
not
support
types
meaning
it
is
not
possible
in
OPC
to
get
information
about
the
type
of
a
node

OPC
however
supports
properties

which
means
it
is
possible
to
browse
the
existing
properties
and
what
properties
a
particular
node
has

DAIS
has
extended
this
to
also
include
types

that
is

it
is
possible
to
browse
existing
types

the
properties
each
type
has
and
each
node
has
a
type


OPC
defines
the
following
property
sets




•

set
1
of
OPC
specific
properties



•

set
2
of
OPC
recommended
properties



•

set
3
of
vendor
specific
properties



In
DAIS

OPC
set
1
properties
cannot
be
browsed
through
the
property-browsing
interface

Property


Instead
access
of
set
1
properties
is
direct
in
the
interfaces
as
parameters
or
struct
members
as
is
the
case
for
OPC

This
means
that
DAIS
exposes
only
OPC
set
2
and
3
properties
through
the
property
browse
interface














OPC
is
a
service
API
providing
access
to
data
managed
by
the
server

The
data

for
example

nodes

items

areas

sources

conditions

reasons

are
not
instantiated
as
objects
at
the
client

This
means
that
OPC
does
not
define
any
particular
APIs
for
the
data
instances
that
a
client
can
deal
with
directly

OPC
has
a
few
coarse
objects
like
OPCGroup
and
OPCEventSubscription
supporting
the
data
access

DAIS
has
adopted
this
principle
and
is
identical
to
OPC
in
this
respect


In
OPC
each
client
has
its
own
OPC
server
object

In
DAIS
there
is
only
one
DAIS
server
object
shared
by
all
clients

To
support
individual
client
sessions
a
new
session
interface
is
defined

There
is
one
interface
for
data
access
session
objects
and
one
for
alarms
&
events
session
objects

The
session
objects
correspond
to
the
OPC
server
object


The
OPC
server
object
has
interfaces
for
browsing
server
data

for
example

IOPCBrowseServerAddressSpace
and
IOPCEventAreaBrowser

and
information
model

for
example

IOPCItemProperties


In
DAIS
each
type
of
data
has
its
own
object
for
browsing

these
objects
are
called
“home?
objects

The
OPC
browse
interface
methods
are
hence
divided
among
the
different
home
objects







Many
OPC
interface

method

and
parameter
names
have
been
kept
but
recasted
according
to
the
CORBA
style
guide

But
many
OPC
names
have
been
replaced
by
new
names
to
more
clearly
indicate
the
meaning

This
is
particularly
the
case
for
the
browse
and
alarms
&
events
APIs









In
OPC
it
is
common
to
return
arrays
of
HRESULTs
corresponding
to
arrays
of
data

In
the
case
where
the
data
did
not
contain
any
errors
an
array
with
“no
error
occurred?
codes
still
is
returned

In
DAIS
such
error
codes
will
be
returned
as
a
sequence
of
error
structs
identifying
the
erroneous
data
and
an
error
code

In
case
of
no
errors
the
sequence
of
error
structs
is
empty









OPC
data
accesses
use
both
server
and
client
side
handles
created
based
on
identification
texts
for
nodes
and
items

To
make
the
translation
from
identification
texts
to
handles
fast
and
avoid
repeated
translation
in
OPC
an
intermediate
server
side
identifier
called
the
blob
exists

In
DAIS
the
server
side
handles
and
blobs
are
replaced
by
identifiers
based
on
ResourceIDs

both
for
nodes
and
items


For
a
description
of
ResourceIDs
refer
to

Section
2
2

“Data
Access
Facility

DAF

?
on
page
2-4

The
OPC
client
side
handles
are

still
kept
in
DAIS









COM
OPC
use
the
standard
interfaces
IConnectionPoint
to
set
up
callbacks

In
DAIS
callbacks
are
set
up
directly
between
server
and
client
by
updating
an
attribute
holding
the
callback
object









The
COM
style
enumerators
in
OPC
are
replaced
by
CORBA
style
iterators
in
DAIS









In
OPC
multiple
parallel
vectors
often
pass
data

In
DAIS
a
single
vector
holding
structs

thus
reducing
the
number
of
parameters

replaces
the
parallel
vectors









In
OPC
all
methods
return
the
HRESULT
error
value

In
DAIS
HRESULTs
are
replaced
by
exceptions
and
out
parameters
are
returned
as
method
results
instead

Only
in
a
few
cases
are
there
additional
output
parameters
in
DAIS









In
OPC
data
is
generally
organized
in
hierarchical
structures

In
data
access
the
leafs
are
called
leaf
nodes
and
the
branches
branch
nodes
or
items

A
leaf
node
or
item
is
the
same
as
an
instance
of
property
at
an
object

A
branch
node
corresponds
to
an




•

Object
having
properties




•

Arbitrary
organization
of
other
branch
nodes




•

Object
having
both
properties
and
other
branch
nodes
as
children




In
DAIS
data
access
the
branch
nodes
are
called
nodes
and
the
leaf
nodes
are
called
items

In
DAIS
alarms
&
events

the
branch
nodes
are
called
areas
and
the
leaf
nodes
sources


In
OPC
branch
and
leaf
nodes
have
a
name
unique
among
the
nodes
or
items
that
are
children
of
the
same
node

A
second
name
is
formed
by
combining
these
names
from
each
branch
node
in
the
path
from
the
node
or
leaf
to
the
root

Both
names
are
called
ItemIDs
in
OPC
and
the
name
created
by
following
the
path
to
the
root
is
sometimes
called
a
fully
qualified
ItemID


In
DAIS
the
name
unique
among
the
child’s
to
the
same
node
is
called
label
and
the
name
including
the
labels
from
all
nodes
in
the
path
to
the
root
is
called
pathname

Both
DAIS
branch
nodes
and
leaf
nodes
have
both
a
label
and
a
pathname


A
label
is
used
in
the
same
way
as
a
name
but
the
word
label
is
preferred
before
the
word
name
as
it
denotes
something
that
is
atomic

that
is

it
cannot
be
further
divided









OPC
provides
a
server
side
cursor
from
where
browsing
is
made
and
the
OPC
interface
provides
methods
to
move
the
cursor


DAIS
does
not
provide
server
side
cursors
and
requires
the
client
to
keep
track
of
browse
positions
themselves

The
reason
for
removing
server
side
cursors
is
it
makes
clean
up
after
crashed
clients
easier
and
simplifies
the
server
design









OPC
does
not
support
types
meaning
it
is
not
possible
in
OPC
to
get
information
about
the
type
of
a
node

OPC
however
supports
properties

which
means
it
is
possible
to
browse
the
existing
properties
and
what
properties
a
particular
node
has

DAIS
has
extended
this
to
also
include
types

that
is

it
is
possible
to
browse
existing
types

the
properties
each
type
has
and
each
node
has
a
type


OPC
defines
the
following
property
sets




•

set
1
of
OPC
specific
properties



•

set
2
of
OPC
recommended
properties



•

set
3
of
vendor
specific
properties



In
DAIS

OPC
set
1
properties
cannot
be
browsed
through
the
property-browsing
interface

Property


Instead
access
of
set
1
properties
is
direct
in
the
interfaces
as
parameters
or
struct
members
as
is
the
case
for
OPC

This
means
that
DAIS
exposes
only
OPC
set
2
and
3
properties
through
the
property
browse
interface












The
UMS
DAF
and
DAIS
are
server
APIs
for
access
of
object
data
rather
than
the
data
objects
themselves







The
DAF
describes
a
generic
interface
for
navigating
and
reading
data
from
complex
data
structures
including
relations
between
objects

Both
DAF
and
DAIS
support
navigation
in
a
space
of
hierarchically
structured
objects

an
object
is
called
a
node
in
DAIS
and
a
resource
in
DAF


Both
support
identification
of
objects
and
properties
at
an
object

In
DAIS
an
instance
of
property
at
an
object
is
called
an
item
and
an
ItemID

item
identifier

identifies
an
item

An
ItemID
consists
of
a
ResourceID

resource
identifier

for
the
node
and
a
PropertyID

property
identifier

for
the
property

The
DAIS
API
uses
ItemIDs
to
access
data
while
the
DAF
uses
ResourceIDs
and
PropertyIDs
separated


A
system
may
implement
both
a
DAF
server
and
a
DAIS
server

In
such
a
system
it
shall
be
assumed
that
the
same
object
will
have
the
same
ResourceID
seen
through
either
API

This
means
it
shall
be
possible
to
navigate
to
an
object

retrieve
its
ResourceID
through
one
of
the
APIs

and
use
that
ResourceID
with
the
other
API

In
the
same
way
PropertyIDs
are
the
same


Textual
identification
of
resources
and
properties
in
the
DAF
is
by
URIs

Uniform
Resource
Identifier


ResourceIDs
and
PropertyIDs
have
their
own
URIs

URIs
can
be
translated
into
corresponding
ResourceIDs
and
PropertyIDs
and
vice
versa

A
property
name
is
a
URI
where
the
container
part
is
a
unique
schema
identifier
and
the
fragment
part
is
the
property
name


For
example


http


www
epri
com
schema
CIM-07f
xml#Measurement
positiveFlowIn

DAIS
does
not
support
URIs
directly
but
has
a
textual
representation
for
nodes

items

types

and
properties

This
textual
representation
may
correspond
to
the
fragment
part
of
a
URI










In
the
case
where
a
system
supports
both
the
DAF
and
the
DAIS
interfaces
it
is
expected
that
the
same
object
will
be
identified
by
the
same
ResourceID
through
both
interfaces
and
the
same
property
by
the
same
PropertyID

Sameness
of
objects
and
properties

however

depends
on
the
information
model
exposed
through
the
two
interfaces
and
if
the
information
models
are
different

then
a
mapping
is
required


In
the
case
where
a
system
supports
both
the
DAF
and
the
DAIS
interfaces
it
is
expected
that
the
same
objects
will
be
identified
by
the
same
ResourceID
and
URI
fragment
through
both
interfaces
and
the
same
property
by
the
same
PropertyID
and
URI
fragment


The
exact
mapping
has
to
be
described
for
each
DAIS
item
–
DAF
property
pair
according
to
the
underlying
information
models


Section
4
1
5

“Utility
SCADA
EMS

Measurement
Model
?
on
page
4-5
elaborates
on
the
information
model
and
a
detailed

mapping
between
IEC
61970-30x
and
the
DAIS
can
be
found
in
Section
4
1
5

“Utility

SCADA
EMS
Measurement
Model
?
on
page
4-5



The
foregoing
concepts
are
fundamental
enough
that
they
should
find
equivalents
in
any

data
repository

Some

perhaps
approximate

equivalents
are
given
in
Table
2-1
as
a

guide


Table
2-1
Mappings
between
modeling
languages



RDF

DAF

Relational
Model

UML

DAIS



Resource

Resource

ResourceID

Tuple

i
e


row


Object

Node

ResourceID



Property

Property

PropertyID

Attribute

i
e


column

or
foreign
key

Attribute
or
association

Property

PropertyID



Class

Class

ClassID

Relation

i
e


table


Class

Type

TypeID



Resource
Description

Resource
Description

Tuple
value

-
Sequence
<ItemState>



URI

URI

ResourceID

Key
value

-



Value

SimpleValue

Field
value

-
SimpleValue



-
ResourceID
and
PropertyID
pair

-
-
Item

ItemID











DAIS
uses
the
DAF
SimpleValue
type
for
data
transferred
over
the
API
instead
of
the
OPC
type
VARIANT

The
data
types
used
in
OPC
are
Microsoft
COM
types
and
as
DAIS
is
a
CORBA
API
a
mapping
of
the
data
types
is
needed

The
translation
of
OPC
COM
data
types
to
DAF
CORBA
data
types
is
listed
below


Table
2-2
Mappings
between
OPC
and
DAF
data
types



OPC
COM
basic
types

DAF
Simple
Value
types



-
ResourceID

RESOURCE
TYPE




-
URI

URI
TYPE




LPWSTR

VT
BSTR


string

STRING
TYPE




BOOL

VT
BOOL


boolean

BOOLEAN
TYPE




LONG

VT
R4


long

INT
TYPE




DWORD

VT
I4


unsigned
long

UNSIGNED
TYPE




double

VT
R8


double

DOUBLE
TYPE




-
Complex

COMPLEX
TYPE




FILETIME

VT
Date


DateTime

DATE
TIME
TYPE




-
ULongLong

ULONG
LONG
TYPE




WORD

VT
I2


unsigned
long

UNSIGNED
TYPE




FLOAT

VT
R4


double

DOUBLE
TYPE




BYTE

VT
UI1


-


HRESULT

VT
ERROR


-


VARIANT

VARTYPE


SimpleValue

SimpleValueType














The
DAF
describes
a
generic
interface
for
navigating
and
reading
data
from
complex
data
structures
including
relations
between
objects

Both
DAF
and
DAIS
support
navigation
in
a
space
of
hierarchically
structured
objects

an
object
is
called
a
node
in
DAIS
and
a
resource
in
DAF


Both
support
identification
of
objects
and
properties
at
an
object

In
DAIS
an
instance
of
property
at
an
object
is
called
an
item
and
an
ItemID

item
identifier

identifies
an
item

An
ItemID
consists
of
a
ResourceID

resource
identifier

for
the
node
and
a
PropertyID

property
identifier

for
the
property

The
DAIS
API
uses
ItemIDs
to
access
data
while
the
DAF
uses
ResourceIDs
and
PropertyIDs
separated


A
system
may
implement
both
a
DAF
server
and
a
DAIS
server

In
such
a
system
it
shall
be
assumed
that
the
same
object
will
have
the
same
ResourceID
seen
through
either
API

This
means
it
shall
be
possible
to
navigate
to
an
object

retrieve
its
ResourceID
through
one
of
the
APIs

and
use
that
ResourceID
with
the
other
API

In
the
same
way
PropertyIDs
are
the
same


Textual
identification
of
resources
and
properties
in
the
DAF
is
by
URIs

Uniform
Resource
Identifier


ResourceIDs
and
PropertyIDs
have
their
own
URIs

URIs
can
be
translated
into
corresponding
ResourceIDs
and
PropertyIDs
and
vice
versa

A
property
name
is
a
URI
where
the
container
part
is
a
unique
schema
identifier
and
the
fragment
part
is
the
property
name


For
example


http


www
epri
com
schema
CIM-07f
xml#Measurement
positiveFlowIn

DAIS
does
not
support
URIs
directly
but
has
a
textual
representation
for
nodes

items

types

and
properties

This
textual
representation
may
correspond
to
the
fragment
part
of
a
URI









In
the
case
where
a
system
supports
both
the
DAF
and
the
DAIS
interfaces
it
is
expected
that
the
same
object
will
be
identified
by
the
same
ResourceID
through
both
interfaces
and
the
same
property
by
the
same
PropertyID

Sameness
of
objects
and
properties

however

depends
on
the
information
model
exposed
through
the
two
interfaces
and
if
the
information
models
are
different

then
a
mapping
is
required


In
the
case
where
a
system
supports
both
the
DAF
and
the
DAIS
interfaces
it
is
expected
that
the
same
objects
will
be
identified
by
the
same
ResourceID
and
URI
fragment
through
both
interfaces
and
the
same
property
by
the
same
PropertyID
and
URI
fragment


The
exact
mapping
has
to
be
described
for
each
DAIS
item
–
DAF
property
pair
according
to
the
underlying
information
models


Section
4
1
5

“Utility
SCADA
EMS

Measurement
Model
?
on
page
4-5
elaborates
on
the
information
model
and
a
detailed

mapping
between
IEC
61970-30x
and
the
DAIS
can
be
found
in
Section
4
1
5

“Utility

SCADA
EMS
Measurement
Model
?
on
page
4-5



The
foregoing
concepts
are
fundamental
enough
that
they
should
find
equivalents
in
any

data
repository

Some

perhaps
approximate

equivalents
are
given
in
Table
2-1
as
a

guide


Table
2-1
Mappings
between
modeling
languages



RDF

DAF

Relational
Model

UML

DAIS



Resource

Resource

ResourceID

Tuple

i
e


row


Object

Node

ResourceID



Property

Property

PropertyID

Attribute

i
e


column

or
foreign
key

Attribute
or
association

Property

PropertyID



Class

Class

ClassID

Relation

i
e


table


Class

Type

TypeID



Resource
Description

Resource
Description

Tuple
value

-
Sequence
<ItemState>



URI

URI

ResourceID

Key
value

-



Value

SimpleValue

Field
value

-
SimpleValue



-
ResourceID
and
PropertyID
pair

-
-
Item

ItemID










DAIS
uses
the
DAF
SimpleValue
type
for
data
transferred
over
the
API
instead
of
the
OPC
type
VARIANT

The
data
types
used
in
OPC
are
Microsoft
COM
types
and
as
DAIS
is
a
CORBA
API
a
mapping
of
the
data
types
is
needed

The
translation
of
OPC
COM
data
types
to
DAF
CORBA
data
types
is
listed
below


Table
2-2
Mappings
between
OPC
and
DAF
data
types



OPC
COM
basic
types

DAF
Simple
Value
types



-
ResourceID

RESOURCE
TYPE




-
URI

URI
TYPE




LPWSTR

VT
BSTR


string

STRING
TYPE




BOOL

VT
BOOL


boolean

BOOLEAN
TYPE




LONG

VT
R4


long

INT
TYPE




DWORD

VT
I4


unsigned
long

UNSIGNED
TYPE




double

VT
R8


double

DOUBLE
TYPE




-
Complex

COMPLEX
TYPE




FILETIME

VT
Date


DateTime

DATE
TIME
TYPE




-
ULongLong

ULONG
LONG
TYPE




WORD

VT
I2


unsigned
long

UNSIGNED
TYPE




FLOAT

VT
R4


double

DOUBLE
TYPE




BYTE

VT
UI1


-


HRESULT

VT
ERROR


-


VARIANT

VARTYPE


SimpleValue

SimpleValueType












Interfaces
defined
in
COM
and
CORBA
IDL
differ
in
a
number
of
ways

Important
differences
concerning
interface
definitions
are

•
object
referencing




•

interface
management




•

error
management

and



•

IDL




A
detailed
description
of
the
mapping
can
be
found
in
the
CORBA
2
3
specification

chapters
17

18

and
19







In
CORBA
each
object
is
uniquely
referenced
in
one
step

In
COM
obtaining
an
object
usually
is
a
two
step
process

In
the
first
step
a
stateless
server
object
is
obtained

In
the
second
step
the
server
object
is
loaded
with
state
data

In
CORBA
an
object
is
a
unique
individual
that
contains
state
from
the
very
beginning










A
CORBA
object
has
a
single
interface

This
interface
can
be
built
from
several
other
interfaces
through
inheritance

The
resulting
interface
might
have
many
methods
and
hence
become
big

A
COM
object
usually
has
multiple
interfaces
and
supports
the
client
to
detect
and
navigate
between
these
interfaces
at
run
time

As
a
CORBA
interface
is
defined
by
inheritance
it
has
to
be
fully
defined
at
compile
time

As
COM
allows
run
time
detection
of
interfaces

the
IUnknown

QueryInterface


method

a
full
match
between
interfaces
implemented
by
a
server
and
interfaces
known
to
a
client
is
not
required


Mapping
OPC
interfaces
to
DAIS
interfaces
can
be
done
in
two
ways




1
	
Inherit
a
number
of
OPC
interfaces
into
one
CORBA
object

This
may
result
in
name
clashes
that
require
renaming
of
methods




2
	
Instantiate
an
OPC
interface
as
an
own
CORBA
object
referenced
by
a
container
object




Both
techniques
are
used
in
the
DAIS
specification










CORBA
provides
exceptions
for
error
handling
and
COM
does
not

COM
provides
error
status
through
a
return
parameter
called
HRESULT

The
caller
has
to
explicitly
test
the
HRESULT
to
decide
if
the
operation
was
successful

HRESULT
return
parameters
are
replaced
by
CORBA
exceptions










The
COM
and
CORBA
IDL
have
several
syntactical
differences
and
use
different
style
guides












In
CORBA
each
object
is
uniquely
referenced
in
one
step

In
COM
obtaining
an
object
usually
is
a
two
step
process

In
the
first
step
a
stateless
server
object
is
obtained

In
the
second
step
the
server
object
is
loaded
with
state
data

In
CORBA
an
object
is
a
unique
individual
that
contains
state
from
the
very
beginning









A
CORBA
object
has
a
single
interface

This
interface
can
be
built
from
several
other
interfaces
through
inheritance

The
resulting
interface
might
have
many
methods
and
hence
become
big

A
COM
object
usually
has
multiple
interfaces
and
supports
the
client
to
detect
and
navigate
between
these
interfaces
at
run
time

As
a
CORBA
interface
is
defined
by
inheritance
it
has
to
be
fully
defined
at
compile
time

As
COM
allows
run
time
detection
of
interfaces

the
IUnknown

QueryInterface


method

a
full
match
between
interfaces
implemented
by
a
server
and
interfaces
known
to
a
client
is
not
required


Mapping
OPC
interfaces
to
DAIS
interfaces
can
be
done
in
two
ways




1
	
Inherit
a
number
of
OPC
interfaces
into
one
CORBA
object

This
may
result
in
name
clashes
that
require
renaming
of
methods




2
	
Instantiate
an
OPC
interface
as
an
own
CORBA
object
referenced
by
a
container
object




Both
techniques
are
used
in
the
DAIS
specification









CORBA
provides
exceptions
for
error
handling
and
COM
does
not

COM
provides
error
status
through
a
return
parameter
called
HRESULT

The
caller
has
to
explicitly
test
the
HRESULT
to
decide
if
the
operation
was
successful

HRESULT
return
parameters
are
replaced
by
CORBA
exceptions









The
COM
and
CORBA
IDL
have
several
syntactical
differences
and
use
different
style
guides










DAIS

as
well
as
OPC

structure
nodes
and
items
hierarchically

Nodes
and
items
have
a
label
uniquely
identifying
child’s
located
at
the
same
node

The
labels
from
the
nodes
in
the
path
from
a
node
or
item
to
the
root
form
a
pathname

The
pathname
uniquely
identifies
a
node
or
item
in
the
tree


The
same
principle
for
naming
objects
is
described
in
the
IEC
1346-1
standard

IEC
1346-1
call
labels
for
single
level
designation
and
the
pathname
for
multi
level
designation
and
supports
multiple
hierarchical
structures

The
DAIS
supports
multiple
structures
by
allowing
multiple
views
where
each
view
exposes
one
structure








The
IEC
61970-30x
[8]
draft
standard

also
named
CIM

describes
a
specific
organization
of
power
system
objects
in
a
hierarchical
structure

DAIS
is
transparent
to
the
structure
and
hence
supports
the
IEC
61970
structure


DAIS
is
also
transparent
to
what
attributes
are
defined
as
long
as
they
can
be
reached
through
the
hierarchy

DAIS
however
defines
a
set
of
attributes
that
a
DAIS
server
is
expected
to
support

Some
of
these
attributes
can
also
be
found
in
IEC
61970-30x

A
detailed
attribute
mapping
is
provided
later
in
this
specification
and
is
further
elaborated

in
Section
4
1
5

“Utility
SCADA
EMS
Measurement
Model
?
on
page
4-5







The
W3C
XPath
[13]
standard
describes
how
navigation
in
a
hierarchical
structure

i
e


an
XML
document

is
made
using
an
expression


In
DAIS

navigation
is
made
using
the
various
browse
APIs

However
in
one
place
there
is
a
need
to
describe
navigation
paths
as
expressions
and
that
is
for
the
condition
logic
in
Alarms
and
Events












Contents

This
chapter
contains
the
following
sections




Section
Title

Page




“Common
Declarations?



3-1





“Server?



3-30




This
section
describes
the
DAISServer
and
IDL
common
to
the
server

data
access

and
alarms
&
events











To
support
universal
character
encodings
the
UTF-8
Unicode
standard
[12]
shall
be
used
for
characters
and
strings










The
DAIS
relies
on
the
Data
Access
Facility

DAF

for
basic
data
type
declarations
and
some
DAF
declarations

for
example

ResourceID
and
SimpleValue

are
included
because
of
this

DAIS
common
declarations

for
example

DAIS

Quality

are
made
in
DAISCommon

Interfaces
for
nodes

types

properties

and
sessions
are
also
common
between
data
access
and
alarms
&
events

The
Interface
Definition
Language

IDL

files

and
dependencies
listed
in
Figure
3-1
are
defined





DAFIdentifiers



DAFDescriptions



DAISSession
DAISCommon
DAISNode
DAISProperty
DAISType

Figure
3-1
Dependencies
among
common
IDL
files









Refer
to
the
Data
Access
Facility
specification
[2]










Refer
to
the
Data
Access
Facility
specification
[2]













File

DAISCommon
idl#ifndef

DAIS
COMMON
IDL#define

DAIS
COMMON
IDL#pragma
prefix
"omg
org"#include
<DAFDescriptions
idl>module
DAIS{typedef
unsigned
short
SupportedFunctions
const
SuportedFunctions
DAIS
DATA
ACCESS
=0x0001
const
SupportedFunctions
DAIS
ALARMS
AND
EVENTS
=0x0002

typedef
DAFDescriptions

ResourceID
ResourceID
typedef
DAFDescriptions

SimpleValueType
SimpleValueType
typedef
DAFDescriptions

SimpleValue
SimpleValue
typedef
DAFDescriptions

DateTime

DateTime
typedef
DAFDescriptions

PropertyID
PropertyID
typedef
DAFDescriptions

PropertyValueSequence
PropertyValues




sequences
of
resource
idstypedef
sequence<ResourceID>
ResourceIDs
typedef
sequence<PropertyID>
PropertyIDs

truct
ItemID{ResourceID
resource
PropertyID
property
}
typedef
sequence<ItemID>
ItemIDs

typedef
unsigned
long
ClientItemHandle
typedef
sequence<ClientItemHandle>
ClientItemHandles
typedef
unsigned
long
long
ServerItemHandle
typedef
sequence<ServerItemHandle>
ServerItemHandles

typedef
short
ServerItemIdentificationType
const
ServerItemIdentificationType
ITEM
ID
=
0
const
ServerItemIdentificationType
PATH
NAME
=
1

union
ServerItemIdentification
switch

ServerItemIdentificationType




{





case
ITEM
ID


ItemID

item





case
PATH
NAME

string

pathname




}







typedef
sequence<ServerItemIdentification>ServerItemIdentifications


typedef
unsigned
short
Error

struct
ItemError
{

Error
err


ClientItemHandle
client
handle


ServerItemHandle
server
handle


string
pathname


string
reason

}

typedef
sequence<ItemError>
ItemErrors





error
codes
const
Error
ERROR
DAISOK
=
0

const
Error
ERROR
BAD
RIGHTS
=
1

const
Error
ERROR
UNKNOWN
ITEMID
=
2

const
Error
ERROR
CLAMPED
=
3

const
Error
ERROR
OUT
OF
RANGE
=
4

const
Error
ERROR
UNKNOWN
PATHNAME
=
5

const
Error
ERROR
BAD
TYPE
=
6

const
Error
ERROR
UNKNOWN
ACCESS
PATH
=
7

const
Error
ERROR
INTERNAL
SERVER
=
8

const
Error
ERROR
INVALID
DAIS
HANDLE
=
9


enum
AccessRights
{

READABLE

WRITEABLE


READ
AND
WRITEABLE
}


typedef
unsigned
long
OPCQuality

typedef
unsigned
long
UserQuality


struct
Quality
{

OPCQuality
opc
quality


UserQuality
user
quality

}





Masks
for
extracting
quality
subfields



note
'status'
mask
also
includes
'Quality'
bits

const
OPCQuality
OPC
QUALITY
MASK
=
0x000000C0

const
OPCQuality
OPC
STATUS
MASK
=
0x000000FC

const
OPCQuality
OPC
LIMIT
MASK
=
0x00000003





Values
for
QUALITY
MASK
bit
field

const
OPCQualityOPC
QUALITY
BAD
=
0x00000000

const
OPCQuality
OPC
QUALITY
UNCERTAIN
=
0x00000040

const
OPCQualityOPC
QUALITY
GOOD
=
0x000000C0





STATUS
MASK
Values
for
Quality
=
BAD

const
OPCQuality
OPC
QUALITY
CONFIG
ERROR
=
0x00000004

const
OPCQuality
OPC
QUALITY
NOT
CONNECTED
=
0x00000008

const
OPCQuality
OPC
QUALITY
DEVICE
FAILURE
=
0x0000000C

const
OPCQuality
OPC
QUALITY
SENSOR
FAILURE
=
0x00000010

const
OPCQuality
OPC
QUALITY
LAST
KNOWN
=
0x00000014

const
OPCQuality
OPC
QUALITY
COMM
FAILURE
=
0x00000018

const
OPCQuality
OPC
QUALITY
OUT
OF
SERVICE
=
0x0000001C





STATUS
MASK
Values
for
Quality
=
UNCERTAIN

const
OPCQuality
OPC
QUALITY
LAST
USABLE
=
0x00000044

const
OPCQuality
OPC
QUALITY
SENSOR
CAL
=
0x00000050

const
OPCQuality
OPC
QUALITY
EGU
EXCEEDED
=
0x00000054

const
OPCQuality
OPC
QUALITY
SUB
NORMAL
=
0x00000058

const
OPCQuality
DAIS
QUALITY
OCILLATORY
=
0x0000005C





STATUS
MASK
Values
for
Quality
=
GOOD



const
OPCQuality
OPC
QUALITY
LOCAL
OVERRIDE=
0xD8



use
EXQ
Source
xxx
instead
of
OPC
QUALITY
LOCAL
OVERRIDE




Values
for
Limit
Bitfield

const
OPCQualityOPC
LIMIT
OK
=
0x00000000

const
OPCQualityOPC
LIMIT
LOW
=
0x00000001

const
OPCQualityOPC
LIMIT
HIGH
=
0x00000002

const
OPCQualityOPC
LIMIT
CONST
=
0x00000003




DAIS
Quality
extension
masks
const
OPCQuality
EXQ
SOURCE
MASK
=
0x00000700
const
OPCQuality
EXQ
TEST
MASK
=
0x00000800
const
OPCQuality
EXQ
OPERATOR
BLOCKED
MASK
=
0x00001000
const
OPCQuality
EXQ
TIMESTAMP
ACCURACY
MASK
=
0x00006000



DAIS
Quality
source
extensionconst
OPCQuality
EXQ
SOURCE
NONE
=
0x00000000
const
OPCQuality
EXQ
SOURCE
PROCESS
=
0x00000100
const
OPCQuality
EXQ
SOURCE
PRIMARY
SUBSTITUTED
=
0x00000200
const
OPCQuality
EXQ
SOURCE
INHERITED
SUBSTITUTED=
0x00000300
const
OPCQuality
EXQ
SOURCE
CORRECTED
=
0x00000400
const
OPCQuality
EXQ
SOURCE
DEFAULTED
=
0x00000500



DAIS
Time
stamp
accuracyconst
OPCQuality
EXQ
TS
ACC
10
MSEC
=
0x00000000
const
OPCQuality
EXQ
TS
ACC
100
MSEC
=
0x00002000
const
OPCQuality
EXQ
TS
ACC
SECOND
=
0x00004000
const
OPCQuality
EXQ
TS
ACC
BAD
TIME
=
0x00006000
}
#endif




DAIS
COMMON
IDL
SupportedFunctions

This
constant
tells
what
functions
the
DAIS
server

i
e


Data
access

Alarms
&
Events

or
both

supports

In
case
the
server
is
extended
with
other
functions
they
are
included
as
well

e
g


Historical
Data
functionality

HDAIS




DAF
declarations

These
declarations

for
example

ResourceID

import
DAF
declarations
to
DAIS


ItemID

A
pair
of
a
ResourceID
and
a
PropertyID

It
uniquely
identifies
an
item

that
is

a
property
at
a
node




Member

Description



resource

The
ResourceID




property

The
PropertyID




ClientItemHandle

A
client
created
numeric
handle
used
by
the
client
to
efficiently
identify
data
coming
from
the
server
in
callbacks


ServerItemHandle

A
server
created
numeric
handle
used
by
the
server
to
efficiently
identify
items
in
client
calls


ServerItemIdentification

A
union
that
holds
either
an
ItemID
or
a
pathname

Either
can
be
used
for
identification
of
an
item


Error

Numeric
error
codes
that
are
returned
by
ItemError




EnumValue

Description



ERROR
DAISOK

Used
to
indicate
an
error
free
result




ERROR
BAD
RIGHTS

The
Items
AccessRights
do
not
allow
the
operation




ERROR
UNKNOWN
ITEMID

The
resource
or
property
in
the
ItemID
is
unknown




ERROR
CLAMPED

A
value
passed
to
WRITE
was
accepted
but
the
output
was
clamped




ERROR
OUT
OF
RANGE

The
value
was
out
of
range




ERROR
UNKNOWN
PATHNAME

The
pathname
was
not
recognised




ERROR
BAD
TYPE

The
server
cannot
convert
the
data
between
the
specified
format

requested
data
type
and
the
canonical
data
type




ERROR
UNKNOWN
ACCESS
PATH

The
item's
access
path
is
unknown




ERROR
INTERNAL
SERVER

An
error
has
appeared
in
the
server
due
to
some
server
internal
problem




ERROR
INVALID
DAIS
HANDLE

A
client
or
server
handle
was
invalid




ItemError

A
struct
for
reporting
of
item
related
errors




Member

Description



err

An
error
code
as
described
below




client
handle

The
client
side
handle
identifying
the
item




server
handle

The
server
side
handle
identifying
the
item




pathname

The
pathname
for
display
or
presentation
purposes




reason

An
additional
text
explaining
the
error




AccessRights

Numeric
access
rights
supported
per
item




EnumValue

Description



READABLE

Read
only
data




WRITEABLE

Write
only
data




READ
AND
WRITABLE

Both
read
and
write
data




OPCQuality

A
flag
word
giving
the
OPC
quality

Each
flag
has
a
specific
meaning
as
described
below

Four
groups
of
flags
exist




1


Main
quality
telling
if
a
value
is
good

bad

or
suspected




2


Detailed
quality




3


Limits
telling
if
the
value
is
stuck




4


Historical
data
access
flags

Those
flags
are
described
in
the
HDAIS
specification

Bit
masks
are
defined
to
extract
these
flags




Quality

status

and
limit
bit
masks



Mask

Description



OPC
QUALITY
MASK

Bit
mask
for
main
quality




OPC
STATUS
MASK

Bit
mask
for
detailed
quality




OPC
LIMIT
MASK

Bit
mask
for
the
limits




Main
quality
enumeration
numbers



Enum

Description



OPC
QUALITY
BAD

The
number
for
bad
quality




OPC
QUALITY
UNCERTAIN

The
number
for
uncertain
quality




OPC
QUALITY
GOOD

The
number
for
good
quality




After
application
of
the
OPC
QUALITY
MASK
the
quality
shall
be
compared
directly
to
the
enumeration
numbers
to
decide
the
quality


Detailed
quality
flags
for
bad
quality



Flag

Description



OPC
QUALITY
CONFIG
ERROR

There
is
a
server
configuration
error
concerning
this
value




OPC
QUALITY
NOT
CONNECTED

The
source
of
the
value
is
not
connected




OPC
QUALITY
DEVICE
FAILURE

A
device
failure
has
been
detected




OPC
QUALITY
SENSOR
FAILURE

A
sensor
failure
has
been
detected




OPC
QUALITY
LAST
KNOWN

The
updating
has
stopped
but
there
is
an
old
value
available




OPC
QUALITY
COMM
FAILURE

Communication
has
failed
and
no
value
available




OPC
QUALITY
OUT
OF
SERVICE

The
updating
of
the
value
is
manually
blocked
for
update

the
item
is
not
active





Detailed
quality
flags
for
uncertain
quality



Flag

Description



OPC
QUALITY
LAST
USABLE

The
value
is
old

The
time
stamp
gives
the
age




OPC
QUALITY
EGU
EXCEEDED

The
value
is
beyond
the
capability
of
representation

for
example

counter
overflow





OPC
QUALITY
SENSOR
CAL

The
sensor
calibration
is
bad




OPC
QUALITY
SUB
NORMAL

Value
is
derived
from
multiple
sources
where
the
majority
has
less
than
required
good
quality




DAIS
QUALITY
OCILLATORY

If
a
binary
value
changes
cyclically
with
a
frequency
higher
than
a
specific
threshold

it
is
oscillating

This
quality
compliant
with
IEC
61850-7-3




Definition
of
limit
flags



Flag

Description



OPC
LIMIT
OK

The
value
is
not
limited

that
is

it
moves
freely
up
or
down




OPC
LIMIT
LOW

The
value
is
stuck
at
a
low
limit






OPC
LIMIT
HIGH
The
value
is
stuck
at
a
high
limit

OPC
LIMIT
CONST
The
value
is
stuck
constant


DAIS
Quality
extension
masks

The
part
of
the
flag
word
giving
the
DAIS
extended
quality

Each
flag
has
a
specific
meaning
as
described
below

These
quality
definitions
are
based
on
the
revised
IEC
61850-7-3
definitions
of
quality

The
following
masks
are
defined




Mask

Description



EXQ
SOURCE
MASK

Bit
mask
for
the
source




EXQ
TEST
MASK

Bit
mask
for
the
test
status

The
test
status
indicates
that
the
value
is
generated
by
a
test
and
shall
not
be
regarded
as
an
operational
value




EXQ
OPERATOR
BLOCKED
MASK

Bit
mask
for
the
operator
blocked
status

The
status
indicates
that
the
value
has
been
blocked
for
update
and
is
old

The
OPC
QUALITY
LAST
USABLE
quality
shall
be
set
as
well




EXQ
TIMESTAMP
ACCURACY
MASK

Bit
mask
for
the
time
stamp
accuracy




Flags
defining
source



Flag

Description



EXQ
SOURCE
NONE

There
is
no
source
for
this
data
item

The
code
is
used
for
spare
items
not
yet
allocated




EXQ
SOURCE
PROCESS

The
source
for
this
value
is
the
process




EXQ

SOURCE
PRIMARY

SUBSTITUTED

The
value
is
manually
substituted




EXQ
SOURCE
INHERITED

SUBSTITUTED

A
substituted
value
has
been
copied
or
used
as
input
to
some
calculation

The
result
value
is
then
marked
with
EXQ
SOURCE
INHERITED

SUBSTITUTED




EXQ
SOURCE
CORRECTED

An
alternate
and
more
accurate
value
has
been
calculated
by
some
application

e
g


a
State
Estimator


If
this
value
has
been
used
to
correct
the
original
value

it
shall
be
indicated
EXQ
SOURCE
CORRECTED




EXQ
REMOTE
DEFAULTED

The
value
is
initialized
by
a
default
value




Flags
defining
time
stamp
quality



Flag

Description



EXQ
LOCAL
NONEEXQ
TS
ACC

10
MSEC

The
value
is
not
updated
locally

i
e


it
has
a
remote
source
specification


The
flags

=0

indicate
that
the
accuracy
is
10
milliseconds
or
better

IEC61850-7-2
performance
class
T0





EXQ
LOCAL
SUBSTITUTEDEXQ
TS

ACC
100
MSEC

The
value
is
locally
substituted

manually


The
flags

=1

indicate
that
the
accuracy
is
100
milliseconds
or
better




EXQ
LOCAL
SE
REPLACEDEXQ
TS

ACC
SECOND

The
value
is
locally
substituted
by
State
Estimator

The
flags

=2

indicate
that
the
accuracy
is
in
the
range
of
seconds
or
better




EXQ
TS
ACC
BAD
TIME

The
flags

=3

indicate
that
the
time
stamp
is
bad




QualityThe
DAIS
quality
consists
of
OPCQuality
and
ExtendedQuality



Member

Description



opc
quality

The
quality
as
specified
by
OPC
including
extensions
from
DAIS




user
quality

A
user
specific
quality












Methods
that
return
information
about
more
than
one
resource
may
return
an
iterator

The
resource
description
iterator
allows
a
client
to
access
a
large
query
result
sequentially

several
resources
at
a
time

This
is
necessary
where
the
ORB
limits
message
sizes

It
also
enables
implementations
to
overlap
the
client
and
server
processing
of
query
results

if
necessary



The
client
and
the
data
provider
should
cooperate
to
manage
the
lifetime
of
the
iterator
and
the
resources
it
consumes

The
destroy


and
next
n


methods
allow
the
client
and
data
provider
respectively
to
indicate
that
the
iterator
may
be
destroyed



In
addition

the
data
provider
may
autonomously
destroy
the
iterator
at
any
time

for
resource
management
or
other
reasons


If
a
client
detects
that
an
iterator
has
been
destroyed

it
will
not
interpret
this
condition
in
itself
as
either
an
indication
that
the
end
of
the
iteration
has
been
reached

or
as
a
permanent
failure
of
the
data
provider


next
n



This
operation
returns
possibly
0
and
at
most
n
resource
descriptions
in
the
form
of
a
resource
description
sequence

In
all
cases
the
state
of
the
iteration
is
indicated
by
the
Boolean
return
value




•	
True
means
that
there
may
be
more
resource
descriptions
beyond
those
returned
so
far




•	
False
means
all
the
resource
descriptions
have
now
been
returned

No
further
calls
are
expected
for
this
iterator
and
the
data
provider
may
destroy
the
iterator
at
any
time
after
the
call
returns




reset



This
operation
resets
the
iterator
to
the
first
element


clone



This
operation
returns
a
copy
of
the
iterator


destroy



This
operation
is
used
to
terminate
iteration
before
all
the
resource
descriptions
have
been
returned

After
destroy


is
invoked
no
further
calls
are
expected
for
this
iterator


The
data
provider
may
destroy
the
iterator
at
any
time
after
the
call
returns
















A
node
may
represent
a
real
world
object
such
as
a
location
or
a
piece
of
equipment

A
node
may
also
represent
a
schema
item
such
as
a
type
or
property

Nodes
correspond
to
“branches?
in
the
IOPCBrowseServerAddressSpace
or
IOPCEventAreaBrowser
interfaces

Nodes
correspond
to
Resources
in
the
RDF
model
and
the
DAF
interface

Each
node
has
a
universal
identity
given
by
its
ResourceID

The
ResourceID
of
a
node
is
the
same
in
all
views
provided
by
a
DAIS
server

DAIS
servers
may
be
coordinated
with
DAF
servers
so
that
a
node
has
the
same
ResourceID
as
the
corresponding
resource

Each
node
has
zero
or
more
child
s


A
child
may
be
another
node
or
any
other
type
of
object

for
example

data
access
items
or
alarms
&
event
sources


Each
node
has
a
type

The
type
determines
what
other
types
of
child
objects
a
node
has


Nodes
are
arranged
in
a
strict
hierarchy
for
naming
purposes

A
DAIS
server
may
provide
more
than
one
such
hierarchy

each
is
called
a
view


The
view
is
selected
when
the
session
is
initiated


Within
a
view

each
node

except
for
the
root
node

has
a
single
parent
node

a
label
that
is
unique
among
all
nodes
with
the
same
parent

and
a
unique
pathname

A
node’s
pathname
is
a
string
that
contains
its
label
and
the
pathname
of
its
parent

The
pathname
must
be
a
valid
URI

but
apart
from
that
the
syntax
of
pathnames
is
implementation
dependent


The
Node
IDL
defines
a
main
interface
DAIS

Node

IHome
for
browsing
among
the
hierarchically
structured
nodes

Nodes
are
described
by
DAIS

Node

Description
struct




DAIS

Node

Iterator
max
left


next
n


reset


clone


destroy


<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids


<<Interface>>
0

n
1
0

n1Node
id


ResourceID
label


string
type


ResourceID
0

n0
1

n1NodeItemComponent
pathname


string
1
0

*
+parent
10

*
Figure
3-2
DAIS
node
IDL
in
UML











File

DAISNode
idl
#ifndef

DAIS
NODE
IDL
#define

DAIS
NODE
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
Node
{

struct
Description



{





ResourceID

id





ResourceID

parent





string

label





string

descrip





ResourceID

type





boolean

is
leaf




}






typedef
sequence<
Description
>
Descriptions


interface
Iterator
{
boolean
next
n






in

unsigned
long

n





out

Descriptions

nodes












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownResourceID
{string
reason
}

exception
InvalidFilter
{string
reason
}

exception
UnkownTypeID
{string
reason
}


Description
find


in
ResourceID
node


raises

UnknownResourceID



Descriptions
find
each


in
ResourceIDs
nodes


raises

UnknownResourceID



Iterator
find
by
parent


in
ResourceID
node

in
string
filter
criteria



raises

UnknownResourceID

InvalidFilter



Iterator
find
by
type


in
ResourceID
node

in
string
filter
criteria

in
ResourceIDs
type
filter



raises

UnknownResourceID

InvalidFilter

UnknownTypeID



Strings
get
pathnames


in
ResourceIDs
nodes




ResourceIDs
get
ids


in
Strings
pathnames




}
}
}

#endif




DAIS
NODE
IDL

Description

A
struct
describing
a
node




Member

Description



id

The
identification
of
this
node




parent

The
identification
of
the
parent
node




label

The
label

single
level
designation

of
the
node




descrip

A
descriptive
text
for
the
node




type

A
reference
to
the
type
of
the
node




is
leaf

Indicate
if
the
node
is
a
leaf

i
e


it
has
no
child
nodes





Iterator


Refer
to
Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10

This
interface
corresponds

to
the
OPC
interface
EnumString
with
the
difference
that
the
Iterator
returns
the
Description
struct
instead
of
a
string


IHome

An
interface
used
for
browsing
nodes

The
interface
corresponds
to
the
IOPCBrowseServerAddressSpace
with
the
BrowseFilterType
set
to
OPC
BRANCH
or
the
IOPCEventAreaBrowser

A
major
difference
to
OPC
is
that
the
server
does
not
provide
a
cursor
for
clients

Instead
clients
have
to
provide
the
browse
position
in
each
call


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

For
methods
taking
a
sequence
of
resource
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


InvalidFilter

An
exception
telling
the
filter
criteria
string
is
not
correct

The
likely
reason
behind
this
exception
is
an
erroneously
entered
string


UnknownTypeID

An
exception
telling
one
or
more
TypeIDs
does
not
exist


find



For
a
given
node

return
information
about
that
node




Parameter

Description



node

A
node
identification




return

The
node
description




find
each




For
a
sequence
of
nodes

return
information
about
each
node




Parameter

Description



nodes

A
sequence
of
node
identifications




return

An
iterator
holding
the
node
descriptions




find
by
parent




For
a
given
node

return
all
child
nodes
at
that
node

Hence
to
reach
leaf
nodes
using
this
method
repeated
calls
must
be
made
for
each
level

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
BRANCH





Parameter

Description



node

The
parent
node
identification




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
nodes
with
a
pathname
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





return

An
iterator
holding
the
child
node
descriptions




find
by
type



For
a
sub-tree
given
by
the
node
parameter

return
all
child
nodes
of
the
specified
type

This
will
return
all
leaf
nodes
under
the
given
sub-tree
root
node

There
is
no

corresponding
operation
in
OPC

Refer
to
Section
4
2
4
1

“DAIS

Item
Overview
?
on

page
4-15
for
a
description
of
how
item
browsing
is
mapped
to
OPC





Parameter
Description
node
The
identification
of
the
node
defining
the
sub-tree




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
nodes
with
a
pathname
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





type
filter

A
list
of
TypeIDs

Nodes
matching
any
of
the
TypeIDs
will
be
held
by
the
returned
iterator




return

An
iterator
holding
descriptions
for
the
found
nodes




get
pathnames



Translate
a
sequence
of
node
identifications
to
the
corresponding
sequence
of
pathnames

If
a
node
fails
to
translate
to
a
pathname

due
to
an
unknown
node
identification


the
corresponding
pathname
is
an
empty
string




Parameter

Description



nodes

The
sequence
of
nodes




return

The
corresponding
sequence
of
pathnames




get
ids



Translate
a
sequence
of
pathnames
to
the
corresponding
sequence
of
node
identifications

If
a
pathname
fails
to
translate
to
a
node
identification

due
to
an
unrecognized
pathname


the
corresponding
node
identification
is
NULL




Parameter

Description



pathnames

The
sequence
of
pathnames




return

The
corresponding
sequence
of
node
identifications




















A
type
represents
a
set
of
related
properties
and
associations

Each
node
has
a
type
and
all
the
properties
represented
by
that
type
apply
to
the
node

Each
type
is
identified
by
a
ResourceID
and
has
a
label
and
description

A
type
may
be
obtained
for
any
node
using
the
node’s
TypeID

Related
types
may
be
grouped
into
a
schema

A
ResourceID
identifies
each
schema

All
the
types
in
a
schema
may
be
obtained
given
the
schema
ResourceID

A
schema
and
its
type
may
be
represented
as
nodes
in
one
or
more
of
views
provided
by
a
DAIS
server

When
a
schema
is
represented
as
a
node

the
node’s
ResourceID
and
the
schema
ResourceID
are
identical

Similarly

when
a
type
is
represented
as
a
node

the
node’s
ResourceID
and
the
type’s
ResourceID
are
identical

The
type’s
parent
is
always
the
node
representing
its
schema

the
type’s
label
is
identical
to
the
node
label
and
the
type’s
description
is
identical
to
the
node
description


The
type
IDL
defines
a
main
interface
DAIS

Type

IHome
for
browsing
supported
types




DAIS

Type

IHome
find


find
by
schema


<<Interface>>

+aggregated
types


11


0

n0

n



0

n0

n


11


0

n0

n



Type
id


ResourceID
schema


ResourceID
label


string
description


string



DAIS

Type

Iterator
max
left


next
n


destroy


<<Interface>>







Figure
3-3
DAIS
type
IDL
in
UML







File
DAISType
idl



#ifndef

DAIS
TYPE
IDL



#define

DAIS
TYPE
IDL



#pragma
prefix
"omg
org"



#include
"DAISCommon
idl"



module
DAIS
{



module
Type
{



struct
Description
{



ResourceID

id




ResourceID

schema




string

label




string

descrip




ResourceIDs

aggregated
types




}





typedef
sequence<Description>

Descriptions




interface
Iterator




{




boolean
next
n






in
unsigned
long

n




out
Descriptions

types










void
reset


Iterator
clone


void
destroy



}


interface
IHome
{
exception
UnknownResourceID
{string
reason
}


Description
find

in
ResourceID
type

raises

UnknownResourceID


Iterator
find
by
schema


in
ResourceID
schema



raises

UnknownResourceID


}
}
}

#endif




DAIS
TYPE
IDL

Description

A
struct
describing
a

type




Member

Description



id

The
identification
of
this
type




schema

The
identification
of
the
schema
where
the
type
is
defined




label

The
label
of
the
type




descrip

A
description
of
the
type




aggregated
types

A
sequence
of
type
identifications
that
a
node
of
this
type
may
contain

This
information
is
intended
as
a
guide
when
the
type
filter
is
specified
for
the
find
by
type


methods




IHome

An
object
used
to
browse
the
types

There
is
no
corresponding
interface
in
OPC


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find



For
a
given
type

return
information
about
that
type




Parameter

Description



type

A
type
identification




return

The
type
description




find
by
schema



For
a
given
schema

find
all
types
defined
by
that
schema




Parameter

Description



schema

The
identification
of
the
schema




return

A
sequence
of
type
descriptions




















A
property
represents
a
characteristic
of
a
node
that
can
be
described
with
a
value

A
given
property
may
apply
to
many
nodes

for
each
such
node
there
will
be
an
item

corresponding
to
the
property


See
Section
4
2
4

“DAISItem
IDL
?
on
page
4-15




A
DAIS
property
corresponds
to
a
property
in
RDF
and
the
DAF

A
DAIS
property
corresponds
to
the
concept
of
a
property
in
OPC
accessed
with
the
IOPCItemProperties

QueryAvailableProperties


method

However

the
six
core
OPC
properties

timestamp

quality

value

do
not
correspond
to
properties
in
DAIS

They
are
given
special
treatment
in
OPC

they
are
not
the
same
as
other
OPC
properties


See

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15
for
interfaces
to
handle
these



Each
property
is
identified
by
a
ResourceID
and
has
a
label

description

and
canonical
data
type

The
canonical
data
type
is
a
member
of
the
SimpleType
enumeration
and
indicates
the
preferred
CORBA
atomic
data
type
for
values
of
this
property

Every
item
of
a
given
property
has
an
identical
canonical
data
type

A
property
may
be
obtained
for
any
item
via
the
property
member
of
the
ItemID

All
properties
that
apply
to
a
given
node
may
be
obtained

given
the
node’s
ResourceID

All
properties
that
apply
to
the
nodes
of
a
given
type
may
be
obtained

given
the
TypeID

A
property
may
be
represented
as
a
node
in
one
or
more
of
views
provided
by
a
DAIS
server

In
this
case
the
node’s
ResourceID
and
the
property’s
ResourceID
are
identical

The
property’s
parent
is
always
the
node
representing
the
type
to
which
it
belongs

The
property’s
label
is
identical
to
the
node
label
and
the
property’s
description
is
identical
to
the
node
description


The
property
IDL
defines
a
main
interface
DAIS

Property

IHome
for
browsing
properties

The
information
model
describing
how
the
properties
are
related
to
nodes
and
items
is
found

in
Section
4
1
1

“Nodes

Items

Types

and
Properties
?
on
page
4-2





Property
id


PropertyID
label


string
description


string
canonical
data
type


SimpleValueType
DAIS

Property

IHome
<<Interface>>
find


find
each


find
by
node


find
by
type


0

n
1
0

n1
Figure
3-4
DAIS
property
IDL
in
UML











File

DAISProperty
idl#ifndef

DAIS
PROPERTY
IDL#define

DAIS
PROPERTY
IDL#pragma
prefix
"omg
org"#include
<DAISCommon
idl>
module
DAIS
{module
Property
{
struct
Description
{
PropertyID
id

string
label

string
descrip

SimpleValueType
canonical
data
type


}
typedef
sequence<Description>
Descriptions

interface
IHome
{
exception
UnknownResourceID
{string
reason
}


Description
find


in
PropertyID
property


raises

UnknownResourceID



Descriptions
find
each


in
PropertyIDs
properties


raises

UnknownResourceID



Descriptions
find
by
node


in
ResourceID
node


raises

UnknownResourceID



Descriptions
find
by
type


in
ResourceID
type



raises

UnknownResourceID


}
}
}

#endif




DAIS
PROPERTY
IDL

Description

Describe
a
property




Member

Description



id

The
identification
of
this
property




label

The
label

single
level
designation

of
the
property




descrip

A
description
of
the
property




canonical
data
type

The
data
type
used
for
the
property
in
the
server




Home

An
object
used
for
browsing
properties
defined
for
a
type
or
existing
at
a
node

It
corresponds
to
the
OPC
interface
IOPCItemProperties


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find



For
a
given
property

return
information
about
that
property




Parameter

Description



property

A
property
identification




return

The
property
description




find
each



For
a
given
property

return
information
about
that
property




Parameter

Description



properties

A
sequence
of
property
identifications




return

The
sequence
of
property
descriptions




find
by
node




For
a
node

return
information
about
each
property
describing
its
items

This
method
corresponds
to
IOPCItemProperties

QueryAvailableProperties






Parameter

Description



node

A
node
identification




return

A
sequence
of
property
descriptions




find
by
type




For
a
given
type

return
all
property
descriptions




Parameter

Description



type

A
type
identification




return

A
sequence
of
property
descriptions




















The
session
is
an
interface
inherited
by
data
access
and
alarms
&
events
sessions

A
session
represents
a
single
conversation
with
the
DAIS
service

A
session
has
a
connection
to
a
shut
down
callback
used
by
a
server
to
shut
down
clients
in
the
case
of
an
ordered
shut
down
of
the
server

If
the
session
object
is
destroyed
or
a
failure
is
detected
by
the
server
when
invoking
an
operation
on
any
callback
objects

then
the
session
is
terminated


A
session
object
corresponds
to
the
OPC
server
object

hence
each
OPC
server
object
will
be
represented
by
a
session
object
in
DAIS




Client

fro
m
DA
ISServ
er

DAIS

ShutdownCallback
<<Interface>>
shutdown
notify


1
0

1
10

1DAIS

Session
<<Interface>>
status




DAIS

SessionStatus
callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy


0

1
1
0

11
Figure
3-5
DAIS
session
IDL
in
UML

The
status


method
corresponds
to
the
read
only
SessionStatus
attribute
in
the
IDL

The
callback


get
and
set
methods
correspond
to
the
ShutDownCallback
attribute












File
DAISSession
idl
#ifndef

DAIS
SESSION
IDL
#define

DAIS
SESSION
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{

struct
SessionStatus
{
string
name

DateTime
start
time

DateTime
current
time

DateTime
last
update
time

unsigned
long
group
count

long
band
width


}


interface
ShutdownCallback
{

void
shutdown
notify







in
string

reason












}







interface
Session
{

readonly
attribute
SessionStatusstatus


attribute
ShutdownCallback
callback


void
destroy



}
}

#endif




DAIS
SESSION
IDL

SessionStatus

A
struct
holding
session
status




Parameter

Description



name

Within
the
server
unique
name
of
the
session




start
time

The
time
when
the
session
was
started

This
time
is
not
reset
during
the
session
lifetime




current
time

The
current
time
as
known
by
the
server




last
update
time

The
time
when
the
server
sent
an
event
notification
for
this
session




group
count

The
current
number
of
groups
for
a
data
access
session
or
the
number
of
event
subscriptions
for
an
alarms
&
event
session




band
width

If
held
updated
by
the
server
the
percentage
bandwidth
in
use
for
communication
with
underlying
RTUs
or
devices

A
value
of
100
or
more
indicates
that
more
bandwidth
for
communication
with
devices
is
required
than
available

A
value
of
-1
indicates
the
value
is
unknown
by
the
server




ShutdownCallback

An
object
implemented
by
clients
and
used
by
the
server
to
indicate
that
it
will
shutdown
soon

No
further
calls
should
be
made
and
no
further
data
callbacks
should
be
expected


shutdown
notify





Parameter
Description
reason
An
explanation
of
why
the
server
is
shutting
down


Session

An
interface
representing
a
single
conversation
with
the
DAIS
service

The
interface
is
inherited
into
interfaces
representing
sessions
supporting
specific
services


for
example

data
access
or
alarms
&
events



status
A
read
only
attribute
holding
the
SessionStatus

callback
An
attribute
holding
a
reference
to
a
ShutDownCallback
object

A
client
that
wants
to

receive
shut
down
callbacks
from
a
server
shall
update
the
attribute
with
a
reference
to
a
ShutDownCallback
object


destroy



A
method
for
deletion
of
the
session
object












Some
methods
have
a
filter
string

for
example

the
browse
methods
find
by
type


and
find
by
parent


in
DAISNode
and
DAISItem


The
filter
string
shall
contain
a
pattern
that
is
used
to
match
a
text
string

e
g


the
pathname


The
text
strings
matching
the
pattern
are
passing
the
filter


The
strings
that
may
appear
in
the
filter
string
pattern
are
listed
below




Characters
in
pattern

Matches
in
string



?

Any
single
character




*

Zero
or
more
characters




#

Any
single
digit

0-9





substring

The
specified
substring



[charlist]

Any
single
character
in
charlist




[!charlist]

Any
single
character
not
in
charlist




Some
examples
of
patterns
and
strings
are
given
below




Pattern

String

String
pass
filter



a*a

aBBBa

Yes



[A-Z]

F

Yes



[!A-Z]

F

No



a#a

a2a

Yes



a[L-P]#[!c-e]

aM5b

Yes



B?T*

BAT123khg

Yes



B?T*

CAT123khg

No











This
section
defines
a
little
language
that
is
used
to
describe
logical
expressions
and
navigation
in
structures

A
logical
expression
evaluates
to
true
or
false
and
can
be
used
in
filters
for
collection
of
data
or
definition
of
states

etc

The
condition
logic
described
in

Section
5
2
7

“DAISConditionSpace
IDL
?
on
page
5-32
is
used
to
define
states



In
DAIS
the
data
model
seen
through
the
API
is
a
hierarchical
structure
of
typed
nodes

A
typed
node
may
contain
other
typed
nodes
and
or
property
values

called
items


This

data
model
is
described
in
more
detail
in
Section
4
1

“Information
Model
?
on
page
4-1


In
addition
to
this
hierarchy
DAIS
supports
data
models
where
a
property
value
may
refer
to
one
or
more
other
nodes

Hence
navigation
via
such
references
is
needed
as
well

An
information
model
that
includes
both
hierarchy
and
references
is
the
IEC
61970

briefly
described
in
Section
4
1
5

“Utility
SCADA
EMS
Measurement
Model
?
on

page
4-5



To
be
able
to
navigate
to
nodes
in
the
structure
the
little
language
shall
include
support
for
describing
paths

XML
Path
Language

XPath

[13]
is
a
language
that
supports
navigation
in
structures
and
this
specification
uses
a
subset
of
XPath
as
the
logical
expression
language

XPath
requires
the
exposed
data
model
to
be
hierarchical

even
though
a
model
is
exposed
as
hierarchical
it
may
internally
be
organized
in
other
ways



A
logical
expression
in
XPath
is
called
“PredicateExpr?

statement
9
in
the
XPath
specification
[13]


A
PredicateExpr
evaluates
to
true
or
false

A
logical
expression
in
DAIS
is
called
DAIS
Expression

The
rules
for
a
DAIS
expression
are





•	
DAIS
Expression


=
PredicateExpr


The
following
restrictions
of
the
functionality
described
in
the
XPath
specification
are
defined
for
DAIS
Expression




•	
The
union
operator
"|"
is
not
supported

refer
to
statement
18
in
[13]




•	
The
arithmetic
operators
"+"

"-"

"div"

"*"
and
"mod"
are
not
supported

refer
to
statements
25

26
and
27
in
[13]




•	
unabbreviated
location
paths
is
not
supported




•	
abbreviated
location
paths
is
supported




•	
the
following
axes
are
supported

child

parent

descendant

attribute

and
self




•	
the
following
XPath
functions
are
supported

id



position



not



true



false






The
mapping
between
DAIS
and
XML
data
models
is
listed
below


Table
3-1
Mapping
between
DAIS
and
XML
data
models



DAIS
entity

XML
entity

Comment



Node

A
DAIS
Node
element
that
may
be
contained
by
another
DAIS
node
element


The
DAIS
Node
element
name
is
the
DAIS

Type
name

DAIS

Type

Description
label

referenced
by
DAIS

Node

Description
type

If
the
DAIS
Node
element
has
a
parent
element

the
parent
is
given
by
Node

Description
parent




Node

Description
id

An
id
attribute
of
type
ID
at
a
DAIS
Node
element


Accessed
by
the
id


function



Node

Description
label

A
child
element
of
a
DAIS
Node
element


The
element
name
is
“label
?
The
value
is
Node

Description
label




Table
3-1
Mapping
between
DAIS
and
XML
data
models



DAIS
entity

XML
entity

Comment



Node

Description

descrip

A
child
element
of
a
DAIS
Node
element


The
element
name
is
“description
?
The
value
is
Node

Description
descrip




Item

A
DAIS
Item
element
that
is
child
of
a
DAIS
Node
element


The
element
name
is
the
DAIS

Property
name

DAIS

Property


Description
label

concatenated
with
the
DAIS
Node
element
name
separated
by
a
“
?

The
DAIS

Property
is
given
by
Item

Description
id
property

The
DAIS
Node
parent
element
is
given
by
Item

Description
id
resource




Item

Description
value

The
value
of
the
DAIS
Item
element





XML
data
example

<MeasurementModel>

<Measurement
id="
100">
<label>M100<
label>
<description
>
<Measurement
LimitSets>
200<
Measurement
LimitSets>
<MeasurementValue
id="
500">

<label>TM100<
label><description
><MeasurementValue
value>30<
MeasurementValue
value>
<MeasurementValue
MeasurementValueSource>
400
<
MeasurementValue
MeasurementValueSource>
<
MeasurementValue>

<
Measurement>

<LimitSet
id="
200"><label>summer<
label><description
><Limit
id="
300">
<label>highalarm<
label>
<description
>
<Limit
value>50<
Limit
value>

<
Limit>

<Limit
id="
301">
<label>lowalarm<
label>
<description
>
<Limit
value>-50<
Limit
value>

<
Limit>
<
LimitSet>
<MeasurementValueSource
id="
400">

<label>telemetry<
label>

<description
>

<
MeasurementValueSource>

<
MeasurementModel>


The
XML
data
example
is
based
on
the
UML
schema
in
Figure
4-3
on
page
4-6
and
the



mapping
from
Table
3-1











Through
DAIS
an
operator
gets
access
to
data
in
a
control
system

The
operator
can




•

Read
data

Data
Access

and
alarms
and
events

Alarms
&
Events





•

Write
data


Data
Access




•

Acknowledge
alarms

Alarms
&
Events





Many
control
systems
implement
an
authorization
scheme
where
it
checks
if
an
operator
is
allowed
to
read

write

or
acknowledge


A
DAIS
server
exposes
many
data
objects

If
authorization
is
supported

checks
must
be
made
by
the
server

The
server
must
then
know
who
the
operator
is

An
interface
that
can
be
used
by
the
server
to
get
this
information
is
described
in
the
Security
Service
Specification
[14]

The
Security
Service
Specification
includes
a
rich
interface
supporting
extensive
security
comprising




•

Identification
and
authentication



•

Authorization
and
access
control



•

Security
auditing



•

Security
of
communication



•

Non-repudiation



•

Administration



The
smallest
need
for
a
DAIS
server
is
to
be
able
to
identify
an
operator

a
principal
in
Security
language

so
that
access
control
can
be
made
from
within
the
DAIS
server

Authentication
is
assumed
taken
care
of
at
the
operating
system
login

The
control
of
access
to
a
DAIS
server
itself
within
the
scope
of
a
secure
system
is
not
necessarily
a
requirement

The
other
functions

auditing

secure
communication

non-repudiation

and
administration

supported
by
the
Security
Service
are
not
necessarily
required
for
a
DAIS
server










For
a
DAIS
server
the
following
requirement
levels
for
support
by
the
system
are
defined


0
-	No
authorization
and
no
requirements


1
-	Identification
of
principal
requiring
SecurityLevel1
interfaces

refer
to

[14]
appendix
A


2
-
	Security
levels
as
described
in
[14]
appendix
C

mainly
Security
Functionality
Level
1

















The
DAISServer
IDL
describes
the
DAIS
server
interface
and
depends
on
the
types
of
session
interfaces

for
example

data
access
or
alarms
&
events

it
implements

A
server
not
implementing
a
session
type

data
access
or
alarms
&
events

shall
still
be
capable
of

reporting
the
type
as
not
implemented

The
IDL
files
and
dependencies
in
Figure
3-6
are

defined
below




DAISServer
DAISDASession

from
Data
Access

DAISAES
ession

from
EventAndAlarm
s

DAISSession

from
Com
m
on


Figure
3-6
Dependencies
between
server
IDL
files















The
fundamental
DAIS
service
from
which
session
objects
may
be
obtained

DAIS

Server
would
normally
be
implemented
as
a
persistent
object
accessed
via
the
naming
service
or
the
trader
service

From
the
DAIS

Server
object

the
session
objects
for
data
access
or
alarms
&
events
are
created

A
client
may
create
as
many
session
objects
as
wanted


A
session
can
be
created
for
a
view

A
view
corresponds
to
a
specific
hierarchical
organization
of
objects

also
called
nodes
in
this
specification


The
same
object
may
appear
in
multiple
views
and
hence
in
different
hierarchical
structures

An
example
is
a
breaker
appearing
in
a
functional
structure

having
the
function
of
breaking
current

and
in
a
location
structure

the
place
where
it
is
located


refer
also
to
[10]

Another
example
is
the
same
object
appearing
in
different
areas
of
authority


A
DAIS
server
supporting
data
access
may
have
a
number
of
persistent
public
groups

Public
groups
can
be
used
and
managed
through
the
group
interface

refer
to

Section
4
2
7

“DAISGroup
IDL
?
on
page
4-40


Services
that
are
not
implemented
will
raise
the
CORBA
standard
exception
NO
IMPLEMENT

Not
implemented
exceptions
can
be
expected
for
a
data
accesssession

an
alarms
&
event
session

and
inspection



DAIS

AlarmsAndEvents

Session

from
DAISAESession


<<Interface>>
DAIS

Server
<<Interface>>
status




DAISServerStatus
create
data
access
session


create
data
access
session
for
view


11create
alarms
and
events
session


create
alarms
and
events
session
for
view


find
views


110

0
n
1
n
111
0



n
n

0




Client



0

n0

n



PublicGroup
id


ResourceID
status


DAIS

DataAccess

Group

State



0

n0

n11


0

0
n
n



DAIS

DataAccess

Session

fro
m
DA
IS
DA
Session

<<Interface>>



GroupEntry

from
DAISG
roupEntry


Figure
3-7
DAIS
server
IDL
in
UML











File

DAISServer
idl#ifndef

DAIS
SERVER
IDL#define

DAIS
SERVER
IDL#pragma
prefix
"omg
org"#include
<DAISDASession
idl>#include
<DAISAESession
idl>
module
DAIS
{

enum
ServerState
{SERVER
STATE
RUNNING
SERVER
STATE
FAILED
SERVER
STATE
NOCONFIG
SERVER
STATE
SUSPENDED
SERVER
STATE
TEST
}


struct
ServerStatus
{
DateTime
start
time

DateTime
current
time

ServerState
server
state

unsigned
long
session
count

unsigned
long
major
version

unsigned
long
minor
version

unsigned
long
build
number

string
vendor
info


}


interface
Inspection
{}


interface
Server

{
exception
DuplicateName
{string
reason
}

exception
InvalidView
{string
reason
}


readonly
attribute
ServerStatusstatus
readonly
attribute
SupportedFunctions
supported
functions

DataAccess

Session
create
data
access
session
in
string
session
name

raises

DuplicateName


DataAccess

Session
create
data
access
session
for
view

in
string
session
name

in
string
view
name



raises

DuplicateName

InvalidView



AlarmsAndEvents

Session
create
alarms
and
events
session

in
string
session
name


raises

DuplicateName



AlarmsAndEvents

Session

create
alarms
and
events
session
for
view

in
string
session
name

in
string
view
name


raises

DuplicateName

InvalidView



Strings
find
views




Inspection
inspect




}
}


#endif




DAIS
SERVER
IDL

ServerState

An
enumeration
of
the
states
a
Server
may
have




EnumValue

Description



SERVER
STATE
RUNNING

The
server
is
running
normally

This
is
the
usual
state
for
a
server




SERVER
STATE
FAILED

A
vendor
specific
fatal
error
has
occurred
within
the
server

The
server
is
no
longer
functioning

The
recovery
procedure
from
this
situation
is
vendor
specific




SERVER
STATE
NOCONFIG

The
server
is
running
but
has
no
configuration
information
loaded
and
thus
cannot
function
normally

This
state
implies
that
the
server
needs
configuration
information
in
order
to
function

Servers
that
do
not
require
configuration
information
should
not
return
this
state




SERVER
STATE
SUSPENDED

The
server
has
been
temporarily
suspended
via
some
vendor
specific
method
and
is
not
getting
or
sending
data

Note
that
Quality
will
be
returned
as
OPC
QUALITY
OUT
OF
SERVICE




SERVER
STATE
TEST

The
server
is
in
Test
Mode

The
outputs
are
disconnected
from
the
real
hardware
but
the
server
will
otherwise
behave
normally

Inputs
may
be
real
or
may
be
simulated
depending
on
the
vendor
implementation

Quality
will
generally
be
returned
normally




ServerStatus



Member

Description



start
time

Time
the
server
was
started

This
is
constant
for
the
server
instance
and
is
not
reset
when
the
server
changes
states

Each
instance
of
a
server
should
keep
the
time
when
the
process
started




current
time

The
current
time
as
known
by
the
server




server
state

The
current
status
of
the
server

Refer
to
ServerState
enumeration




session
count

The
total
number
of
sessions
created
by
clients
for
this
server




major
version

The
major
version
of
the
server
software






minor
version

The
minor
version
of
the
server
software




build
number

The
‘build
number’
of
the
server
software




vendor
info

Vendor
specific
string
providing
additional
information
about
the
server

It
is
recommended
that
this
mention
the
name
of
the
company
and
the
type
of
device
s

supported




supported
functions

A
constant
that
tells
what
functions
are
implemented
by
the
DAIS
server

e
g


Data
Access

Alarms
&
Events
or
both



Inspection

An
optional
interface
intended
to
be
specialized
into
a
vendor
specific
inspection
object

The
inspection
object
is
intended
to
expose
server
internal
details
for
debugging
and
inspection
purposes


Server

An
object
implementing
the
DAIS
server

A
DAIS
server
might
provide
more
than
one
view
on
nodes

A
view
is
a
specific
hierarchical
organization
of
nodes
and
nodes
may
appear
in
more
than
one
hierarchical
structure

for
example

a
functional
structure
or
a

location
structure
as
defined
by
IEC
1346-1


refer
also
to
Section
2
4

“IEC
1346-1


Structuring
and
Naming
?
on
page
2-7



DuplicateName

An
exception
raised
when
an
object
is
created
and
the
name
already
exists

No
object
is
created
if
the
exception
is
raised

Is
used
for
session
and
group
manager
objects


InvalidView

An
exception
raised
when
an
invalid
view
is
specified

An
invalid
view
is
if
the
view
name
does
not
exist
or
a
view
not
intended
for
the
type
of
session
is
used

for
example

a
view
for
data
access
is
used
for
alarms
&
events



statusAn
attribute
holding
the
ServerStatus
create
data
access
session


A
method
for
creation
of
a
data
access
session
object

The
default
view
will
be
used




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
data
access
session
for
view



A
method
for
creation
of
a
data
access
session
object
using
a
view
of
nodes




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




view
name

The
name
of
the
view
to
open

If
no
name
is
supplied

the
default
view
will
be
used




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
alarms
and
events
session



A
method
for
creation
of
an
alarms
&
events
session
object

The
default
view
will
be
used




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
alarms
and
events
session
for
view



A
method
for
creation
of
an
alarms
&
events
session
object
using
a
view
of
areas

This
allows
a
server
to
support
different
area
structures
for
different
purposes

for
example

operational
responsibility

workorder
management





Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




view
name

The
name
of
the
view
to
open




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




find
views



A
method
to
get
the
names
for
the
server
supported
views




Parameter
Description
return
A
sequence
of
view
names


inspect



A
method
for
creation
of
an
inspection
object




Parameter
Description
return
The
inspection
object


Session
Management





Client

Client


DAIS

Server
DAIS

ServerDataAccess


DAIS

DataAccess

Session
DataAccess


DAIS

DataAccess

SessionA&E

A&EDAIS

AlarmsAndEvents

SessionD

AIS

AlarmsAndEvents

SessionCreate
a
data
access
session
for
a
specific
structure
and
do
work

e
g

create
groups
and
subscribe
find
views



create
alarms
and
events
session



Do
work
with
alarms
&
events
session
e
g

create
an
AESubscription
create
data
access
session
for
view



Get
the
available
views
destroy



destroy




Figure
3-8
Session
management
interaction











To
support
universal
character
encodings
the
UTF-8
Unicode
standard
[12]
shall
be
used
for
characters
and
strings










The
DAIS
relies
on
the
Data
Access
Facility

DAF

for
basic
data
type
declarations
and
some
DAF
declarations

for
example

ResourceID
and
SimpleValue

are
included
because
of
this

DAIS
common
declarations

for
example

DAIS

Quality

are
made
in
DAISCommon

Interfaces
for
nodes

types

properties

and
sessions
are
also
common
between
data
access
and
alarms
&
events

The
Interface
Definition
Language

IDL

files

and
dependencies
listed
in
Figure
3-1
are
defined





DAFIdentifiers



DAFDescriptions



DAISSession
DAISCommon
DAISNode
DAISProperty
DAISType

Figure
3-1
Dependencies
among
common
IDL
files









Refer
to
the
Data
Access
Facility
specification
[2]










Refer
to
the
Data
Access
Facility
specification
[2]













File

DAISCommon
idl#ifndef

DAIS
COMMON
IDL#define

DAIS
COMMON
IDL#pragma
prefix
"omg
org"#include
<DAFDescriptions
idl>module
DAIS{typedef
unsigned
short
SupportedFunctions
const
SuportedFunctions
DAIS
DATA
ACCESS
=0x0001
const
SupportedFunctions
DAIS
ALARMS
AND
EVENTS
=0x0002

typedef
DAFDescriptions

ResourceID
ResourceID
typedef
DAFDescriptions

SimpleValueType
SimpleValueType
typedef
DAFDescriptions

SimpleValue
SimpleValue
typedef
DAFDescriptions

DateTime

DateTime
typedef
DAFDescriptions

PropertyID
PropertyID
typedef
DAFDescriptions

PropertyValueSequence
PropertyValues




sequences
of
resource
idstypedef
sequence<ResourceID>
ResourceIDs
typedef
sequence<PropertyID>
PropertyIDs

truct
ItemID{ResourceID
resource
PropertyID
property
}
typedef
sequence<ItemID>
ItemIDs

typedef
unsigned
long
ClientItemHandle
typedef
sequence<ClientItemHandle>
ClientItemHandles
typedef
unsigned
long
long
ServerItemHandle
typedef
sequence<ServerItemHandle>
ServerItemHandles

typedef
short
ServerItemIdentificationType
const
ServerItemIdentificationType
ITEM
ID
=
0
const
ServerItemIdentificationType
PATH
NAME
=
1

union
ServerItemIdentification
switch

ServerItemIdentificationType




{





case
ITEM
ID


ItemID

item





case
PATH
NAME

string

pathname




}







typedef
sequence<ServerItemIdentification>ServerItemIdentifications


typedef
unsigned
short
Error

struct
ItemError
{

Error
err


ClientItemHandle
client
handle


ServerItemHandle
server
handle


string
pathname


string
reason

}

typedef
sequence<ItemError>
ItemErrors





error
codes
const
Error
ERROR
DAISOK
=
0

const
Error
ERROR
BAD
RIGHTS
=
1

const
Error
ERROR
UNKNOWN
ITEMID
=
2

const
Error
ERROR
CLAMPED
=
3

const
Error
ERROR
OUT
OF
RANGE
=
4

const
Error
ERROR
UNKNOWN
PATHNAME
=
5

const
Error
ERROR
BAD
TYPE
=
6

const
Error
ERROR
UNKNOWN
ACCESS
PATH
=
7

const
Error
ERROR
INTERNAL
SERVER
=
8

const
Error
ERROR
INVALID
DAIS
HANDLE
=
9


enum
AccessRights
{

READABLE

WRITEABLE


READ
AND
WRITEABLE
}


typedef
unsigned
long
OPCQuality

typedef
unsigned
long
UserQuality


struct
Quality
{

OPCQuality
opc
quality


UserQuality
user
quality

}





Masks
for
extracting
quality
subfields



note
'status'
mask
also
includes
'Quality'
bits

const
OPCQuality
OPC
QUALITY
MASK
=
0x000000C0

const
OPCQuality
OPC
STATUS
MASK
=
0x000000FC

const
OPCQuality
OPC
LIMIT
MASK
=
0x00000003





Values
for
QUALITY
MASK
bit
field

const
OPCQualityOPC
QUALITY
BAD
=
0x00000000

const
OPCQuality
OPC
QUALITY
UNCERTAIN
=
0x00000040

const
OPCQualityOPC
QUALITY
GOOD
=
0x000000C0





STATUS
MASK
Values
for
Quality
=
BAD

const
OPCQuality
OPC
QUALITY
CONFIG
ERROR
=
0x00000004

const
OPCQuality
OPC
QUALITY
NOT
CONNECTED
=
0x00000008

const
OPCQuality
OPC
QUALITY
DEVICE
FAILURE
=
0x0000000C

const
OPCQuality
OPC
QUALITY
SENSOR
FAILURE
=
0x00000010

const
OPCQuality
OPC
QUALITY
LAST
KNOWN
=
0x00000014

const
OPCQuality
OPC
QUALITY
COMM
FAILURE
=
0x00000018

const
OPCQuality
OPC
QUALITY
OUT
OF
SERVICE
=
0x0000001C





STATUS
MASK
Values
for
Quality
=
UNCERTAIN

const
OPCQuality
OPC
QUALITY
LAST
USABLE
=
0x00000044

const
OPCQuality
OPC
QUALITY
SENSOR
CAL
=
0x00000050

const
OPCQuality
OPC
QUALITY
EGU
EXCEEDED
=
0x00000054

const
OPCQuality
OPC
QUALITY
SUB
NORMAL
=
0x00000058

const
OPCQuality
DAIS
QUALITY
OCILLATORY
=
0x0000005C





STATUS
MASK
Values
for
Quality
=
GOOD



const
OPCQuality
OPC
QUALITY
LOCAL
OVERRIDE=
0xD8



use
EXQ
Source
xxx
instead
of
OPC
QUALITY
LOCAL
OVERRIDE




Values
for
Limit
Bitfield

const
OPCQualityOPC
LIMIT
OK
=
0x00000000

const
OPCQualityOPC
LIMIT
LOW
=
0x00000001

const
OPCQualityOPC
LIMIT
HIGH
=
0x00000002

const
OPCQualityOPC
LIMIT
CONST
=
0x00000003




DAIS
Quality
extension
masks
const
OPCQuality
EXQ
SOURCE
MASK
=
0x00000700
const
OPCQuality
EXQ
TEST
MASK
=
0x00000800
const
OPCQuality
EXQ
OPERATOR
BLOCKED
MASK
=
0x00001000
const
OPCQuality
EXQ
TIMESTAMP
ACCURACY
MASK
=
0x00006000



DAIS
Quality
source
extensionconst
OPCQuality
EXQ
SOURCE
NONE
=
0x00000000
const
OPCQuality
EXQ
SOURCE
PROCESS
=
0x00000100
const
OPCQuality
EXQ
SOURCE
PRIMARY
SUBSTITUTED
=
0x00000200
const
OPCQuality
EXQ
SOURCE
INHERITED
SUBSTITUTED=
0x00000300
const
OPCQuality
EXQ
SOURCE
CORRECTED
=
0x00000400
const
OPCQuality
EXQ
SOURCE
DEFAULTED
=
0x00000500



DAIS
Time
stamp
accuracyconst
OPCQuality
EXQ
TS
ACC
10
MSEC
=
0x00000000
const
OPCQuality
EXQ
TS
ACC
100
MSEC
=
0x00002000
const
OPCQuality
EXQ
TS
ACC
SECOND
=
0x00004000
const
OPCQuality
EXQ
TS
ACC
BAD
TIME
=
0x00006000
}
#endif




DAIS
COMMON
IDL
SupportedFunctions

This
constant
tells
what
functions
the
DAIS
server

i
e


Data
access

Alarms
&
Events

or
both

supports

In
case
the
server
is
extended
with
other
functions
they
are
included
as
well

e
g


Historical
Data
functionality

HDAIS




DAF
declarations

These
declarations

for
example

ResourceID

import
DAF
declarations
to
DAIS


ItemID

A
pair
of
a
ResourceID
and
a
PropertyID

It
uniquely
identifies
an
item

that
is

a
property
at
a
node




Member

Description



resource

The
ResourceID




property

The
PropertyID




ClientItemHandle

A
client
created
numeric
handle
used
by
the
client
to
efficiently
identify
data
coming
from
the
server
in
callbacks


ServerItemHandle

A
server
created
numeric
handle
used
by
the
server
to
efficiently
identify
items
in
client
calls


ServerItemIdentification

A
union
that
holds
either
an
ItemID
or
a
pathname

Either
can
be
used
for
identification
of
an
item


Error

Numeric
error
codes
that
are
returned
by
ItemError




EnumValue

Description



ERROR
DAISOK

Used
to
indicate
an
error
free
result




ERROR
BAD
RIGHTS

The
Items
AccessRights
do
not
allow
the
operation




ERROR
UNKNOWN
ITEMID

The
resource
or
property
in
the
ItemID
is
unknown




ERROR
CLAMPED

A
value
passed
to
WRITE
was
accepted
but
the
output
was
clamped




ERROR
OUT
OF
RANGE

The
value
was
out
of
range




ERROR
UNKNOWN
PATHNAME

The
pathname
was
not
recognised




ERROR
BAD
TYPE

The
server
cannot
convert
the
data
between
the
specified
format

requested
data
type
and
the
canonical
data
type




ERROR
UNKNOWN
ACCESS
PATH

The
item's
access
path
is
unknown




ERROR
INTERNAL
SERVER

An
error
has
appeared
in
the
server
due
to
some
server
internal
problem




ERROR
INVALID
DAIS
HANDLE

A
client
or
server
handle
was
invalid




ItemError

A
struct
for
reporting
of
item
related
errors




Member

Description



err

An
error
code
as
described
below




client
handle

The
client
side
handle
identifying
the
item




server
handle

The
server
side
handle
identifying
the
item




pathname

The
pathname
for
display
or
presentation
purposes




reason

An
additional
text
explaining
the
error




AccessRights

Numeric
access
rights
supported
per
item




EnumValue

Description



READABLE

Read
only
data




WRITEABLE

Write
only
data




READ
AND
WRITABLE

Both
read
and
write
data




OPCQuality

A
flag
word
giving
the
OPC
quality

Each
flag
has
a
specific
meaning
as
described
below

Four
groups
of
flags
exist




1


Main
quality
telling
if
a
value
is
good

bad

or
suspected




2


Detailed
quality




3


Limits
telling
if
the
value
is
stuck




4


Historical
data
access
flags

Those
flags
are
described
in
the
HDAIS
specification

Bit
masks
are
defined
to
extract
these
flags




Quality

status

and
limit
bit
masks



Mask

Description



OPC
QUALITY
MASK

Bit
mask
for
main
quality




OPC
STATUS
MASK

Bit
mask
for
detailed
quality




OPC
LIMIT
MASK

Bit
mask
for
the
limits




Main
quality
enumeration
numbers



Enum

Description



OPC
QUALITY
BAD

The
number
for
bad
quality




OPC
QUALITY
UNCERTAIN

The
number
for
uncertain
quality




OPC
QUALITY
GOOD

The
number
for
good
quality




After
application
of
the
OPC
QUALITY
MASK
the
quality
shall
be
compared
directly
to
the
enumeration
numbers
to
decide
the
quality


Detailed
quality
flags
for
bad
quality



Flag

Description



OPC
QUALITY
CONFIG
ERROR

There
is
a
server
configuration
error
concerning
this
value




OPC
QUALITY
NOT
CONNECTED

The
source
of
the
value
is
not
connected




OPC
QUALITY
DEVICE
FAILURE

A
device
failure
has
been
detected




OPC
QUALITY
SENSOR
FAILURE

A
sensor
failure
has
been
detected




OPC
QUALITY
LAST
KNOWN

The
updating
has
stopped
but
there
is
an
old
value
available




OPC
QUALITY
COMM
FAILURE

Communication
has
failed
and
no
value
available




OPC
QUALITY
OUT
OF
SERVICE

The
updating
of
the
value
is
manually
blocked
for
update

the
item
is
not
active





Detailed
quality
flags
for
uncertain
quality



Flag

Description



OPC
QUALITY
LAST
USABLE

The
value
is
old

The
time
stamp
gives
the
age




OPC
QUALITY
EGU
EXCEEDED

The
value
is
beyond
the
capability
of
representation

for
example

counter
overflow





OPC
QUALITY
SENSOR
CAL

The
sensor
calibration
is
bad




OPC
QUALITY
SUB
NORMAL

Value
is
derived
from
multiple
sources
where
the
majority
has
less
than
required
good
quality




DAIS
QUALITY
OCILLATORY

If
a
binary
value
changes
cyclically
with
a
frequency
higher
than
a
specific
threshold

it
is
oscillating

This
quality
compliant
with
IEC
61850-7-3




Definition
of
limit
flags



Flag

Description



OPC
LIMIT
OK

The
value
is
not
limited

that
is

it
moves
freely
up
or
down




OPC
LIMIT
LOW

The
value
is
stuck
at
a
low
limit






OPC
LIMIT
HIGH
The
value
is
stuck
at
a
high
limit

OPC
LIMIT
CONST
The
value
is
stuck
constant


DAIS
Quality
extension
masks

The
part
of
the
flag
word
giving
the
DAIS
extended
quality

Each
flag
has
a
specific
meaning
as
described
below

These
quality
definitions
are
based
on
the
revised
IEC
61850-7-3
definitions
of
quality

The
following
masks
are
defined




Mask

Description



EXQ
SOURCE
MASK

Bit
mask
for
the
source




EXQ
TEST
MASK

Bit
mask
for
the
test
status

The
test
status
indicates
that
the
value
is
generated
by
a
test
and
shall
not
be
regarded
as
an
operational
value




EXQ
OPERATOR
BLOCKED
MASK

Bit
mask
for
the
operator
blocked
status

The
status
indicates
that
the
value
has
been
blocked
for
update
and
is
old

The
OPC
QUALITY
LAST
USABLE
quality
shall
be
set
as
well




EXQ
TIMESTAMP
ACCURACY
MASK

Bit
mask
for
the
time
stamp
accuracy




Flags
defining
source



Flag

Description



EXQ
SOURCE
NONE

There
is
no
source
for
this
data
item

The
code
is
used
for
spare
items
not
yet
allocated




EXQ
SOURCE
PROCESS

The
source
for
this
value
is
the
process




EXQ

SOURCE
PRIMARY

SUBSTITUTED

The
value
is
manually
substituted




EXQ
SOURCE
INHERITED

SUBSTITUTED

A
substituted
value
has
been
copied
or
used
as
input
to
some
calculation

The
result
value
is
then
marked
with
EXQ
SOURCE
INHERITED

SUBSTITUTED




EXQ
SOURCE
CORRECTED

An
alternate
and
more
accurate
value
has
been
calculated
by
some
application

e
g


a
State
Estimator


If
this
value
has
been
used
to
correct
the
original
value

it
shall
be
indicated
EXQ
SOURCE
CORRECTED




EXQ
REMOTE
DEFAULTED

The
value
is
initialized
by
a
default
value




Flags
defining
time
stamp
quality



Flag

Description



EXQ
LOCAL
NONEEXQ
TS
ACC

10
MSEC

The
value
is
not
updated
locally

i
e


it
has
a
remote
source
specification


The
flags

=0

indicate
that
the
accuracy
is
10
milliseconds
or
better

IEC61850-7-2
performance
class
T0





EXQ
LOCAL
SUBSTITUTEDEXQ
TS

ACC
100
MSEC

The
value
is
locally
substituted

manually


The
flags

=1

indicate
that
the
accuracy
is
100
milliseconds
or
better




EXQ
LOCAL
SE
REPLACEDEXQ
TS

ACC
SECOND

The
value
is
locally
substituted
by
State
Estimator

The
flags

=2

indicate
that
the
accuracy
is
in
the
range
of
seconds
or
better




EXQ
TS
ACC
BAD
TIME

The
flags

=3

indicate
that
the
time
stamp
is
bad




QualityThe
DAIS
quality
consists
of
OPCQuality
and
ExtendedQuality



Member

Description



opc
quality

The
quality
as
specified
by
OPC
including
extensions
from
DAIS




user
quality

A
user
specific
quality












Methods
that
return
information
about
more
than
one
resource
may
return
an
iterator

The
resource
description
iterator
allows
a
client
to
access
a
large
query
result
sequentially

several
resources
at
a
time

This
is
necessary
where
the
ORB
limits
message
sizes

It
also
enables
implementations
to
overlap
the
client
and
server
processing
of
query
results

if
necessary



The
client
and
the
data
provider
should
cooperate
to
manage
the
lifetime
of
the
iterator
and
the
resources
it
consumes

The
destroy


and
next
n


methods
allow
the
client
and
data
provider
respectively
to
indicate
that
the
iterator
may
be
destroyed



In
addition

the
data
provider
may
autonomously
destroy
the
iterator
at
any
time

for
resource
management
or
other
reasons


If
a
client
detects
that
an
iterator
has
been
destroyed

it
will
not
interpret
this
condition
in
itself
as
either
an
indication
that
the
end
of
the
iteration
has
been
reached

or
as
a
permanent
failure
of
the
data
provider


next
n



This
operation
returns
possibly
0
and
at
most
n
resource
descriptions
in
the
form
of
a
resource
description
sequence

In
all
cases
the
state
of
the
iteration
is
indicated
by
the
Boolean
return
value




•	
True
means
that
there
may
be
more
resource
descriptions
beyond
those
returned
so
far




•	
False
means
all
the
resource
descriptions
have
now
been
returned

No
further
calls
are
expected
for
this
iterator
and
the
data
provider
may
destroy
the
iterator
at
any
time
after
the
call
returns




reset



This
operation
resets
the
iterator
to
the
first
element


clone



This
operation
returns
a
copy
of
the
iterator


destroy



This
operation
is
used
to
terminate
iteration
before
all
the
resource
descriptions
have
been
returned

After
destroy


is
invoked
no
further
calls
are
expected
for
this
iterator


The
data
provider
may
destroy
the
iterator
at
any
time
after
the
call
returns
















A
node
may
represent
a
real
world
object
such
as
a
location
or
a
piece
of
equipment

A
node
may
also
represent
a
schema
item
such
as
a
type
or
property

Nodes
correspond
to
“branches?
in
the
IOPCBrowseServerAddressSpace
or
IOPCEventAreaBrowser
interfaces

Nodes
correspond
to
Resources
in
the
RDF
model
and
the
DAF
interface

Each
node
has
a
universal
identity
given
by
its
ResourceID

The
ResourceID
of
a
node
is
the
same
in
all
views
provided
by
a
DAIS
server

DAIS
servers
may
be
coordinated
with
DAF
servers
so
that
a
node
has
the
same
ResourceID
as
the
corresponding
resource

Each
node
has
zero
or
more
child
s


A
child
may
be
another
node
or
any
other
type
of
object

for
example

data
access
items
or
alarms
&
event
sources


Each
node
has
a
type

The
type
determines
what
other
types
of
child
objects
a
node
has


Nodes
are
arranged
in
a
strict
hierarchy
for
naming
purposes

A
DAIS
server
may
provide
more
than
one
such
hierarchy

each
is
called
a
view


The
view
is
selected
when
the
session
is
initiated


Within
a
view

each
node

except
for
the
root
node

has
a
single
parent
node

a
label
that
is
unique
among
all
nodes
with
the
same
parent

and
a
unique
pathname

A
node’s
pathname
is
a
string
that
contains
its
label
and
the
pathname
of
its
parent

The
pathname
must
be
a
valid
URI

but
apart
from
that
the
syntax
of
pathnames
is
implementation
dependent


The
Node
IDL
defines
a
main
interface
DAIS

Node

IHome
for
browsing
among
the
hierarchically
structured
nodes

Nodes
are
described
by
DAIS

Node

Description
struct




DAIS

Node

Iterator
max
left


next
n


reset


clone


destroy


<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids


<<Interface>>
0

n
1
0

n1Node
id


ResourceID
label


string
type


ResourceID
0

n0
1

n1NodeItemComponent
pathname


string
1
0

*
+parent
10

*
Figure
3-2
DAIS
node
IDL
in
UML











File

DAISNode
idl
#ifndef

DAIS
NODE
IDL
#define

DAIS
NODE
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
Node
{

struct
Description



{





ResourceID

id





ResourceID

parent





string

label





string

descrip





ResourceID

type





boolean

is
leaf




}






typedef
sequence<
Description
>
Descriptions


interface
Iterator
{
boolean
next
n






in

unsigned
long

n





out

Descriptions

nodes












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownResourceID
{string
reason
}

exception
InvalidFilter
{string
reason
}

exception
UnkownTypeID
{string
reason
}


Description
find


in
ResourceID
node


raises

UnknownResourceID



Descriptions
find
each


in
ResourceIDs
nodes


raises

UnknownResourceID



Iterator
find
by
parent


in
ResourceID
node

in
string
filter
criteria



raises

UnknownResourceID

InvalidFilter



Iterator
find
by
type


in
ResourceID
node

in
string
filter
criteria

in
ResourceIDs
type
filter



raises

UnknownResourceID

InvalidFilter

UnknownTypeID



Strings
get
pathnames


in
ResourceIDs
nodes




ResourceIDs
get
ids


in
Strings
pathnames




}
}
}

#endif




DAIS
NODE
IDL

Description

A
struct
describing
a
node




Member

Description



id

The
identification
of
this
node




parent

The
identification
of
the
parent
node




label

The
label

single
level
designation

of
the
node




descrip

A
descriptive
text
for
the
node




type

A
reference
to
the
type
of
the
node




is
leaf

Indicate
if
the
node
is
a
leaf

i
e


it
has
no
child
nodes





Iterator


Refer
to
Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10

This
interface
corresponds

to
the
OPC
interface
EnumString
with
the
difference
that
the
Iterator
returns
the
Description
struct
instead
of
a
string


IHome

An
interface
used
for
browsing
nodes

The
interface
corresponds
to
the
IOPCBrowseServerAddressSpace
with
the
BrowseFilterType
set
to
OPC
BRANCH
or
the
IOPCEventAreaBrowser

A
major
difference
to
OPC
is
that
the
server
does
not
provide
a
cursor
for
clients

Instead
clients
have
to
provide
the
browse
position
in
each
call


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

For
methods
taking
a
sequence
of
resource
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


InvalidFilter

An
exception
telling
the
filter
criteria
string
is
not
correct

The
likely
reason
behind
this
exception
is
an
erroneously
entered
string


UnknownTypeID

An
exception
telling
one
or
more
TypeIDs
does
not
exist


find



For
a
given
node

return
information
about
that
node




Parameter

Description



node

A
node
identification




return

The
node
description




find
each




For
a
sequence
of
nodes

return
information
about
each
node




Parameter

Description



nodes

A
sequence
of
node
identifications




return

An
iterator
holding
the
node
descriptions




find
by
parent




For
a
given
node

return
all
child
nodes
at
that
node

Hence
to
reach
leaf
nodes
using
this
method
repeated
calls
must
be
made
for
each
level

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
BRANCH





Parameter

Description



node

The
parent
node
identification




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
nodes
with
a
pathname
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





return

An
iterator
holding
the
child
node
descriptions




find
by
type



For
a
sub-tree
given
by
the
node
parameter

return
all
child
nodes
of
the
specified
type

This
will
return
all
leaf
nodes
under
the
given
sub-tree
root
node

There
is
no

corresponding
operation
in
OPC

Refer
to
Section
4
2
4
1

“DAIS

Item
Overview
?
on

page
4-15
for
a
description
of
how
item
browsing
is
mapped
to
OPC





Parameter
Description
node
The
identification
of
the
node
defining
the
sub-tree




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
nodes
with
a
pathname
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





type
filter

A
list
of
TypeIDs

Nodes
matching
any
of
the
TypeIDs
will
be
held
by
the
returned
iterator




return

An
iterator
holding
descriptions
for
the
found
nodes




get
pathnames



Translate
a
sequence
of
node
identifications
to
the
corresponding
sequence
of
pathnames

If
a
node
fails
to
translate
to
a
pathname

due
to
an
unknown
node
identification


the
corresponding
pathname
is
an
empty
string




Parameter

Description



nodes

The
sequence
of
nodes




return

The
corresponding
sequence
of
pathnames




get
ids



Translate
a
sequence
of
pathnames
to
the
corresponding
sequence
of
node
identifications

If
a
pathname
fails
to
translate
to
a
node
identification

due
to
an
unrecognized
pathname


the
corresponding
node
identification
is
NULL




Parameter

Description



pathnames

The
sequence
of
pathnames




return

The
corresponding
sequence
of
node
identifications




















A
type
represents
a
set
of
related
properties
and
associations

Each
node
has
a
type
and
all
the
properties
represented
by
that
type
apply
to
the
node

Each
type
is
identified
by
a
ResourceID
and
has
a
label
and
description

A
type
may
be
obtained
for
any
node
using
the
node’s
TypeID

Related
types
may
be
grouped
into
a
schema

A
ResourceID
identifies
each
schema

All
the
types
in
a
schema
may
be
obtained
given
the
schema
ResourceID

A
schema
and
its
type
may
be
represented
as
nodes
in
one
or
more
of
views
provided
by
a
DAIS
server

When
a
schema
is
represented
as
a
node

the
node’s
ResourceID
and
the
schema
ResourceID
are
identical

Similarly

when
a
type
is
represented
as
a
node

the
node’s
ResourceID
and
the
type’s
ResourceID
are
identical

The
type’s
parent
is
always
the
node
representing
its
schema

the
type’s
label
is
identical
to
the
node
label
and
the
type’s
description
is
identical
to
the
node
description


The
type
IDL
defines
a
main
interface
DAIS

Type

IHome
for
browsing
supported
types




DAIS

Type

IHome
find


find
by
schema


<<Interface>>

+aggregated
types


11


0

n0

n



0

n0

n


11


0

n0

n



Type
id


ResourceID
schema


ResourceID
label


string
description


string



DAIS

Type

Iterator
max
left


next
n


destroy


<<Interface>>







Figure
3-3
DAIS
type
IDL
in
UML







File
DAISType
idl



#ifndef

DAIS
TYPE
IDL



#define

DAIS
TYPE
IDL



#pragma
prefix
"omg
org"



#include
"DAISCommon
idl"



module
DAIS
{



module
Type
{



struct
Description
{



ResourceID

id




ResourceID

schema




string

label




string

descrip




ResourceIDs

aggregated
types




}





typedef
sequence<Description>

Descriptions




interface
Iterator




{




boolean
next
n






in
unsigned
long

n




out
Descriptions

types










void
reset


Iterator
clone


void
destroy



}


interface
IHome
{
exception
UnknownResourceID
{string
reason
}


Description
find

in
ResourceID
type

raises

UnknownResourceID


Iterator
find
by
schema


in
ResourceID
schema



raises

UnknownResourceID


}
}
}

#endif




DAIS
TYPE
IDL

Description

A
struct
describing
a

type




Member

Description



id

The
identification
of
this
type




schema

The
identification
of
the
schema
where
the
type
is
defined




label

The
label
of
the
type




descrip

A
description
of
the
type




aggregated
types

A
sequence
of
type
identifications
that
a
node
of
this
type
may
contain

This
information
is
intended
as
a
guide
when
the
type
filter
is
specified
for
the
find
by
type


methods




IHome

An
object
used
to
browse
the
types

There
is
no
corresponding
interface
in
OPC


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find



For
a
given
type

return
information
about
that
type




Parameter

Description



type

A
type
identification




return

The
type
description




find
by
schema



For
a
given
schema

find
all
types
defined
by
that
schema




Parameter

Description



schema

The
identification
of
the
schema




return

A
sequence
of
type
descriptions




















A
property
represents
a
characteristic
of
a
node
that
can
be
described
with
a
value

A
given
property
may
apply
to
many
nodes

for
each
such
node
there
will
be
an
item

corresponding
to
the
property


See
Section
4
2
4

“DAISItem
IDL
?
on
page
4-15




A
DAIS
property
corresponds
to
a
property
in
RDF
and
the
DAF

A
DAIS
property
corresponds
to
the
concept
of
a
property
in
OPC
accessed
with
the
IOPCItemProperties

QueryAvailableProperties


method

However

the
six
core
OPC
properties

timestamp

quality

value

do
not
correspond
to
properties
in
DAIS

They
are
given
special
treatment
in
OPC

they
are
not
the
same
as
other
OPC
properties


See

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15
for
interfaces
to
handle
these



Each
property
is
identified
by
a
ResourceID
and
has
a
label

description

and
canonical
data
type

The
canonical
data
type
is
a
member
of
the
SimpleType
enumeration
and
indicates
the
preferred
CORBA
atomic
data
type
for
values
of
this
property

Every
item
of
a
given
property
has
an
identical
canonical
data
type

A
property
may
be
obtained
for
any
item
via
the
property
member
of
the
ItemID

All
properties
that
apply
to
a
given
node
may
be
obtained

given
the
node’s
ResourceID

All
properties
that
apply
to
the
nodes
of
a
given
type
may
be
obtained

given
the
TypeID

A
property
may
be
represented
as
a
node
in
one
or
more
of
views
provided
by
a
DAIS
server

In
this
case
the
node’s
ResourceID
and
the
property’s
ResourceID
are
identical

The
property’s
parent
is
always
the
node
representing
the
type
to
which
it
belongs

The
property’s
label
is
identical
to
the
node
label
and
the
property’s
description
is
identical
to
the
node
description


The
property
IDL
defines
a
main
interface
DAIS

Property

IHome
for
browsing
properties

The
information
model
describing
how
the
properties
are
related
to
nodes
and
items
is
found

in
Section
4
1
1

“Nodes

Items

Types

and
Properties
?
on
page
4-2





Property
id


PropertyID
label


string
description


string
canonical
data
type


SimpleValueType
DAIS

Property

IHome
<<Interface>>
find


find
each


find
by
node


find
by
type


0

n
1
0

n1
Figure
3-4
DAIS
property
IDL
in
UML











File

DAISProperty
idl#ifndef

DAIS
PROPERTY
IDL#define

DAIS
PROPERTY
IDL#pragma
prefix
"omg
org"#include
<DAISCommon
idl>
module
DAIS
{module
Property
{
struct
Description
{
PropertyID
id

string
label

string
descrip

SimpleValueType
canonical
data
type


}
typedef
sequence<Description>
Descriptions

interface
IHome
{
exception
UnknownResourceID
{string
reason
}


Description
find


in
PropertyID
property


raises

UnknownResourceID



Descriptions
find
each


in
PropertyIDs
properties


raises

UnknownResourceID



Descriptions
find
by
node


in
ResourceID
node


raises

UnknownResourceID



Descriptions
find
by
type


in
ResourceID
type



raises

UnknownResourceID


}
}
}

#endif




DAIS
PROPERTY
IDL

Description

Describe
a
property




Member

Description



id

The
identification
of
this
property




label

The
label

single
level
designation

of
the
property




descrip

A
description
of
the
property




canonical
data
type

The
data
type
used
for
the
property
in
the
server




Home

An
object
used
for
browsing
properties
defined
for
a
type
or
existing
at
a
node

It
corresponds
to
the
OPC
interface
IOPCItemProperties


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find



For
a
given
property

return
information
about
that
property




Parameter

Description



property

A
property
identification




return

The
property
description




find
each



For
a
given
property

return
information
about
that
property




Parameter

Description



properties

A
sequence
of
property
identifications




return

The
sequence
of
property
descriptions




find
by
node




For
a
node

return
information
about
each
property
describing
its
items

This
method
corresponds
to
IOPCItemProperties

QueryAvailableProperties






Parameter

Description



node

A
node
identification




return

A
sequence
of
property
descriptions




find
by
type




For
a
given
type

return
all
property
descriptions




Parameter

Description



type

A
type
identification




return

A
sequence
of
property
descriptions




















The
session
is
an
interface
inherited
by
data
access
and
alarms
&
events
sessions

A
session
represents
a
single
conversation
with
the
DAIS
service

A
session
has
a
connection
to
a
shut
down
callback
used
by
a
server
to
shut
down
clients
in
the
case
of
an
ordered
shut
down
of
the
server

If
the
session
object
is
destroyed
or
a
failure
is
detected
by
the
server
when
invoking
an
operation
on
any
callback
objects

then
the
session
is
terminated


A
session
object
corresponds
to
the
OPC
server
object

hence
each
OPC
server
object
will
be
represented
by
a
session
object
in
DAIS




Client

fro
m
DA
ISServ
er

DAIS

ShutdownCallback
<<Interface>>
shutdown
notify


1
0

1
10

1DAIS

Session
<<Interface>>
status




DAIS

SessionStatus
callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy


0

1
1
0

11
Figure
3-5
DAIS
session
IDL
in
UML

The
status


method
corresponds
to
the
read
only
SessionStatus
attribute
in
the
IDL

The
callback


get
and
set
methods
correspond
to
the
ShutDownCallback
attribute












File
DAISSession
idl
#ifndef

DAIS
SESSION
IDL
#define

DAIS
SESSION
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{

struct
SessionStatus
{
string
name

DateTime
start
time

DateTime
current
time

DateTime
last
update
time

unsigned
long
group
count

long
band
width


}


interface
ShutdownCallback
{

void
shutdown
notify







in
string

reason












}







interface
Session
{

readonly
attribute
SessionStatusstatus


attribute
ShutdownCallback
callback


void
destroy



}
}

#endif




DAIS
SESSION
IDL

SessionStatus

A
struct
holding
session
status




Parameter

Description



name

Within
the
server
unique
name
of
the
session




start
time

The
time
when
the
session
was
started

This
time
is
not
reset
during
the
session
lifetime




current
time

The
current
time
as
known
by
the
server




last
update
time

The
time
when
the
server
sent
an
event
notification
for
this
session




group
count

The
current
number
of
groups
for
a
data
access
session
or
the
number
of
event
subscriptions
for
an
alarms
&
event
session




band
width

If
held
updated
by
the
server
the
percentage
bandwidth
in
use
for
communication
with
underlying
RTUs
or
devices

A
value
of
100
or
more
indicates
that
more
bandwidth
for
communication
with
devices
is
required
than
available

A
value
of
-1
indicates
the
value
is
unknown
by
the
server




ShutdownCallback

An
object
implemented
by
clients
and
used
by
the
server
to
indicate
that
it
will
shutdown
soon

No
further
calls
should
be
made
and
no
further
data
callbacks
should
be
expected


shutdown
notify





Parameter
Description
reason
An
explanation
of
why
the
server
is
shutting
down


Session

An
interface
representing
a
single
conversation
with
the
DAIS
service

The
interface
is
inherited
into
interfaces
representing
sessions
supporting
specific
services


for
example

data
access
or
alarms
&
events



status
A
read
only
attribute
holding
the
SessionStatus

callback
An
attribute
holding
a
reference
to
a
ShutDownCallback
object

A
client
that
wants
to

receive
shut
down
callbacks
from
a
server
shall
update
the
attribute
with
a
reference
to
a
ShutDownCallback
object


destroy



A
method
for
deletion
of
the
session
object












Some
methods
have
a
filter
string

for
example

the
browse
methods
find
by
type


and
find
by
parent


in
DAISNode
and
DAISItem


The
filter
string
shall
contain
a
pattern
that
is
used
to
match
a
text
string

e
g


the
pathname


The
text
strings
matching
the
pattern
are
passing
the
filter


The
strings
that
may
appear
in
the
filter
string
pattern
are
listed
below




Characters
in
pattern

Matches
in
string



?

Any
single
character




*

Zero
or
more
characters




#

Any
single
digit

0-9





substring

The
specified
substring



[charlist]

Any
single
character
in
charlist




[!charlist]

Any
single
character
not
in
charlist




Some
examples
of
patterns
and
strings
are
given
below




Pattern

String

String
pass
filter



a*a

aBBBa

Yes



[A-Z]

F

Yes



[!A-Z]

F

No



a#a

a2a

Yes



a[L-P]#[!c-e]

aM5b

Yes



B?T*

BAT123khg

Yes



B?T*

CAT123khg

No











This
section
defines
a
little
language
that
is
used
to
describe
logical
expressions
and
navigation
in
structures

A
logical
expression
evaluates
to
true
or
false
and
can
be
used
in
filters
for
collection
of
data
or
definition
of
states

etc

The
condition
logic
described
in

Section
5
2
7

“DAISConditionSpace
IDL
?
on
page
5-32
is
used
to
define
states



In
DAIS
the
data
model
seen
through
the
API
is
a
hierarchical
structure
of
typed
nodes

A
typed
node
may
contain
other
typed
nodes
and
or
property
values

called
items


This

data
model
is
described
in
more
detail
in
Section
4
1

“Information
Model
?
on
page
4-1


In
addition
to
this
hierarchy
DAIS
supports
data
models
where
a
property
value
may
refer
to
one
or
more
other
nodes

Hence
navigation
via
such
references
is
needed
as
well

An
information
model
that
includes
both
hierarchy
and
references
is
the
IEC
61970

briefly
described
in
Section
4
1
5

“Utility
SCADA
EMS
Measurement
Model
?
on

page
4-5



To
be
able
to
navigate
to
nodes
in
the
structure
the
little
language
shall
include
support
for
describing
paths

XML
Path
Language

XPath

[13]
is
a
language
that
supports
navigation
in
structures
and
this
specification
uses
a
subset
of
XPath
as
the
logical
expression
language

XPath
requires
the
exposed
data
model
to
be
hierarchical

even
though
a
model
is
exposed
as
hierarchical
it
may
internally
be
organized
in
other
ways



A
logical
expression
in
XPath
is
called
“PredicateExpr?

statement
9
in
the
XPath
specification
[13]


A
PredicateExpr
evaluates
to
true
or
false

A
logical
expression
in
DAIS
is
called
DAIS
Expression

The
rules
for
a
DAIS
expression
are





•	
DAIS
Expression


=
PredicateExpr


The
following
restrictions
of
the
functionality
described
in
the
XPath
specification
are
defined
for
DAIS
Expression




•	
The
union
operator
"|"
is
not
supported

refer
to
statement
18
in
[13]




•	
The
arithmetic
operators
"+"

"-"

"div"

"*"
and
"mod"
are
not
supported

refer
to
statements
25

26
and
27
in
[13]




•	
unabbreviated
location
paths
is
not
supported




•	
abbreviated
location
paths
is
supported




•	
the
following
axes
are
supported

child

parent

descendant

attribute

and
self




•	
the
following
XPath
functions
are
supported

id



position



not



true



false






The
mapping
between
DAIS
and
XML
data
models
is
listed
below


Table
3-1
Mapping
between
DAIS
and
XML
data
models



DAIS
entity

XML
entity

Comment



Node

A
DAIS
Node
element
that
may
be
contained
by
another
DAIS
node
element


The
DAIS
Node
element
name
is
the
DAIS

Type
name

DAIS

Type

Description
label

referenced
by
DAIS

Node

Description
type

If
the
DAIS
Node
element
has
a
parent
element

the
parent
is
given
by
Node

Description
parent




Node

Description
id

An
id
attribute
of
type
ID
at
a
DAIS
Node
element


Accessed
by
the
id


function



Node

Description
label

A
child
element
of
a
DAIS
Node
element


The
element
name
is
“label
?
The
value
is
Node

Description
label




Table
3-1
Mapping
between
DAIS
and
XML
data
models



DAIS
entity

XML
entity

Comment



Node

Description

descrip

A
child
element
of
a
DAIS
Node
element


The
element
name
is
“description
?
The
value
is
Node

Description
descrip




Item

A
DAIS
Item
element
that
is
child
of
a
DAIS
Node
element


The
element
name
is
the
DAIS

Property
name

DAIS

Property


Description
label

concatenated
with
the
DAIS
Node
element
name
separated
by
a
“
?

The
DAIS

Property
is
given
by
Item

Description
id
property

The
DAIS
Node
parent
element
is
given
by
Item

Description
id
resource




Item

Description
value

The
value
of
the
DAIS
Item
element





XML
data
example

<MeasurementModel>

<Measurement
id="
100">
<label>M100<
label>
<description
>
<Measurement
LimitSets>
200<
Measurement
LimitSets>
<MeasurementValue
id="
500">

<label>TM100<
label><description
><MeasurementValue
value>30<
MeasurementValue
value>
<MeasurementValue
MeasurementValueSource>
400
<
MeasurementValue
MeasurementValueSource>
<
MeasurementValue>

<
Measurement>

<LimitSet
id="
200"><label>summer<
label><description
><Limit
id="
300">
<label>highalarm<
label>
<description
>
<Limit
value>50<
Limit
value>

<
Limit>

<Limit
id="
301">
<label>lowalarm<
label>
<description
>
<Limit
value>-50<
Limit
value>

<
Limit>
<
LimitSet>
<MeasurementValueSource
id="
400">

<label>telemetry<
label>

<description
>

<
MeasurementValueSource>

<
MeasurementModel>


The
XML
data
example
is
based
on
the
UML
schema
in
Figure
4-3
on
page
4-6
and
the



mapping
from
Table
3-1











Through
DAIS
an
operator
gets
access
to
data
in
a
control
system

The
operator
can




•

Read
data

Data
Access

and
alarms
and
events

Alarms
&
Events





•

Write
data


Data
Access




•

Acknowledge
alarms

Alarms
&
Events





Many
control
systems
implement
an
authorization
scheme
where
it
checks
if
an
operator
is
allowed
to
read

write

or
acknowledge


A
DAIS
server
exposes
many
data
objects

If
authorization
is
supported

checks
must
be
made
by
the
server

The
server
must
then
know
who
the
operator
is

An
interface
that
can
be
used
by
the
server
to
get
this
information
is
described
in
the
Security
Service
Specification
[14]

The
Security
Service
Specification
includes
a
rich
interface
supporting
extensive
security
comprising




•

Identification
and
authentication



•

Authorization
and
access
control



•

Security
auditing



•

Security
of
communication



•

Non-repudiation



•

Administration



The
smallest
need
for
a
DAIS
server
is
to
be
able
to
identify
an
operator

a
principal
in
Security
language

so
that
access
control
can
be
made
from
within
the
DAIS
server

Authentication
is
assumed
taken
care
of
at
the
operating
system
login

The
control
of
access
to
a
DAIS
server
itself
within
the
scope
of
a
secure
system
is
not
necessarily
a
requirement

The
other
functions

auditing

secure
communication

non-repudiation

and
administration

supported
by
the
Security
Service
are
not
necessarily
required
for
a
DAIS
server










For
a
DAIS
server
the
following
requirement
levels
for
support
by
the
system
are
defined


0
-	No
authorization
and
no
requirements


1
-	Identification
of
principal
requiring
SecurityLevel1
interfaces

refer
to

[14]
appendix
A


2
-
	Security
levels
as
described
in
[14]
appendix
C

mainly
Security
Functionality
Level
1












To
support
universal
character
encodings
the
UTF-8
Unicode
standard
[12]
shall
be
used
for
characters
and
strings









The
DAIS
relies
on
the
Data
Access
Facility

DAF

for
basic
data
type
declarations
and
some
DAF
declarations

for
example

ResourceID
and
SimpleValue

are
included
because
of
this

DAIS
common
declarations

for
example

DAIS

Quality

are
made
in
DAISCommon

Interfaces
for
nodes

types

properties

and
sessions
are
also
common
between
data
access
and
alarms
&
events

The
Interface
Definition
Language

IDL

files

and
dependencies
listed
in
Figure
3-1
are
defined





DAFIdentifiers



DAFDescriptions



DAISSession
DAISCommon
DAISNode
DAISProperty
DAISType

Figure
3-1
Dependencies
among
common
IDL
files








Refer
to
the
Data
Access
Facility
specification
[2]









Refer
to
the
Data
Access
Facility
specification
[2]












File

DAISCommon
idl#ifndef

DAIS
COMMON
IDL#define

DAIS
COMMON
IDL#pragma
prefix
"omg
org"#include
<DAFDescriptions
idl>module
DAIS{typedef
unsigned
short
SupportedFunctions
const
SuportedFunctions
DAIS
DATA
ACCESS
=0x0001
const
SupportedFunctions
DAIS
ALARMS
AND
EVENTS
=0x0002

typedef
DAFDescriptions

ResourceID
ResourceID
typedef
DAFDescriptions

SimpleValueType
SimpleValueType
typedef
DAFDescriptions

SimpleValue
SimpleValue
typedef
DAFDescriptions

DateTime

DateTime
typedef
DAFDescriptions

PropertyID
PropertyID
typedef
DAFDescriptions

PropertyValueSequence
PropertyValues




sequences
of
resource
idstypedef
sequence<ResourceID>
ResourceIDs
typedef
sequence<PropertyID>
PropertyIDs

truct
ItemID{ResourceID
resource
PropertyID
property
}
typedef
sequence<ItemID>
ItemIDs

typedef
unsigned
long
ClientItemHandle
typedef
sequence<ClientItemHandle>
ClientItemHandles
typedef
unsigned
long
long
ServerItemHandle
typedef
sequence<ServerItemHandle>
ServerItemHandles

typedef
short
ServerItemIdentificationType
const
ServerItemIdentificationType
ITEM
ID
=
0
const
ServerItemIdentificationType
PATH
NAME
=
1

union
ServerItemIdentification
switch

ServerItemIdentificationType




{





case
ITEM
ID


ItemID

item





case
PATH
NAME

string

pathname




}







typedef
sequence<ServerItemIdentification>ServerItemIdentifications


typedef
unsigned
short
Error

struct
ItemError
{

Error
err


ClientItemHandle
client
handle


ServerItemHandle
server
handle


string
pathname


string
reason

}

typedef
sequence<ItemError>
ItemErrors





error
codes
const
Error
ERROR
DAISOK
=
0

const
Error
ERROR
BAD
RIGHTS
=
1

const
Error
ERROR
UNKNOWN
ITEMID
=
2

const
Error
ERROR
CLAMPED
=
3

const
Error
ERROR
OUT
OF
RANGE
=
4

const
Error
ERROR
UNKNOWN
PATHNAME
=
5

const
Error
ERROR
BAD
TYPE
=
6

const
Error
ERROR
UNKNOWN
ACCESS
PATH
=
7

const
Error
ERROR
INTERNAL
SERVER
=
8

const
Error
ERROR
INVALID
DAIS
HANDLE
=
9


enum
AccessRights
{

READABLE

WRITEABLE


READ
AND
WRITEABLE
}


typedef
unsigned
long
OPCQuality

typedef
unsigned
long
UserQuality


struct
Quality
{

OPCQuality
opc
quality


UserQuality
user
quality

}





Masks
for
extracting
quality
subfields



note
'status'
mask
also
includes
'Quality'
bits

const
OPCQuality
OPC
QUALITY
MASK
=
0x000000C0

const
OPCQuality
OPC
STATUS
MASK
=
0x000000FC

const
OPCQuality
OPC
LIMIT
MASK
=
0x00000003





Values
for
QUALITY
MASK
bit
field

const
OPCQualityOPC
QUALITY
BAD
=
0x00000000

const
OPCQuality
OPC
QUALITY
UNCERTAIN
=
0x00000040

const
OPCQualityOPC
QUALITY
GOOD
=
0x000000C0





STATUS
MASK
Values
for
Quality
=
BAD

const
OPCQuality
OPC
QUALITY
CONFIG
ERROR
=
0x00000004

const
OPCQuality
OPC
QUALITY
NOT
CONNECTED
=
0x00000008

const
OPCQuality
OPC
QUALITY
DEVICE
FAILURE
=
0x0000000C

const
OPCQuality
OPC
QUALITY
SENSOR
FAILURE
=
0x00000010

const
OPCQuality
OPC
QUALITY
LAST
KNOWN
=
0x00000014

const
OPCQuality
OPC
QUALITY
COMM
FAILURE
=
0x00000018

const
OPCQuality
OPC
QUALITY
OUT
OF
SERVICE
=
0x0000001C





STATUS
MASK
Values
for
Quality
=
UNCERTAIN

const
OPCQuality
OPC
QUALITY
LAST
USABLE
=
0x00000044

const
OPCQuality
OPC
QUALITY
SENSOR
CAL
=
0x00000050

const
OPCQuality
OPC
QUALITY
EGU
EXCEEDED
=
0x00000054

const
OPCQuality
OPC
QUALITY
SUB
NORMAL
=
0x00000058

const
OPCQuality
DAIS
QUALITY
OCILLATORY
=
0x0000005C





STATUS
MASK
Values
for
Quality
=
GOOD



const
OPCQuality
OPC
QUALITY
LOCAL
OVERRIDE=
0xD8



use
EXQ
Source
xxx
instead
of
OPC
QUALITY
LOCAL
OVERRIDE




Values
for
Limit
Bitfield

const
OPCQualityOPC
LIMIT
OK
=
0x00000000

const
OPCQualityOPC
LIMIT
LOW
=
0x00000001

const
OPCQualityOPC
LIMIT
HIGH
=
0x00000002

const
OPCQualityOPC
LIMIT
CONST
=
0x00000003




DAIS
Quality
extension
masks
const
OPCQuality
EXQ
SOURCE
MASK
=
0x00000700
const
OPCQuality
EXQ
TEST
MASK
=
0x00000800
const
OPCQuality
EXQ
OPERATOR
BLOCKED
MASK
=
0x00001000
const
OPCQuality
EXQ
TIMESTAMP
ACCURACY
MASK
=
0x00006000



DAIS
Quality
source
extensionconst
OPCQuality
EXQ
SOURCE
NONE
=
0x00000000
const
OPCQuality
EXQ
SOURCE
PROCESS
=
0x00000100
const
OPCQuality
EXQ
SOURCE
PRIMARY
SUBSTITUTED
=
0x00000200
const
OPCQuality
EXQ
SOURCE
INHERITED
SUBSTITUTED=
0x00000300
const
OPCQuality
EXQ
SOURCE
CORRECTED
=
0x00000400
const
OPCQuality
EXQ
SOURCE
DEFAULTED
=
0x00000500



DAIS
Time
stamp
accuracyconst
OPCQuality
EXQ
TS
ACC
10
MSEC
=
0x00000000
const
OPCQuality
EXQ
TS
ACC
100
MSEC
=
0x00002000
const
OPCQuality
EXQ
TS
ACC
SECOND
=
0x00004000
const
OPCQuality
EXQ
TS
ACC
BAD
TIME
=
0x00006000
}
#endif




DAIS
COMMON
IDL
SupportedFunctions

This
constant
tells
what
functions
the
DAIS
server

i
e


Data
access

Alarms
&
Events

or
both

supports

In
case
the
server
is
extended
with
other
functions
they
are
included
as
well

e
g


Historical
Data
functionality

HDAIS




DAF
declarations

These
declarations

for
example

ResourceID

import
DAF
declarations
to
DAIS


ItemID

A
pair
of
a
ResourceID
and
a
PropertyID

It
uniquely
identifies
an
item

that
is

a
property
at
a
node




Member

Description



resource

The
ResourceID




property

The
PropertyID




ClientItemHandle

A
client
created
numeric
handle
used
by
the
client
to
efficiently
identify
data
coming
from
the
server
in
callbacks


ServerItemHandle

A
server
created
numeric
handle
used
by
the
server
to
efficiently
identify
items
in
client
calls


ServerItemIdentification

A
union
that
holds
either
an
ItemID
or
a
pathname

Either
can
be
used
for
identification
of
an
item


Error

Numeric
error
codes
that
are
returned
by
ItemError




EnumValue

Description



ERROR
DAISOK

Used
to
indicate
an
error
free
result




ERROR
BAD
RIGHTS

The
Items
AccessRights
do
not
allow
the
operation




ERROR
UNKNOWN
ITEMID

The
resource
or
property
in
the
ItemID
is
unknown




ERROR
CLAMPED

A
value
passed
to
WRITE
was
accepted
but
the
output
was
clamped




ERROR
OUT
OF
RANGE

The
value
was
out
of
range




ERROR
UNKNOWN
PATHNAME

The
pathname
was
not
recognised




ERROR
BAD
TYPE

The
server
cannot
convert
the
data
between
the
specified
format

requested
data
type
and
the
canonical
data
type




ERROR
UNKNOWN
ACCESS
PATH

The
item's
access
path
is
unknown




ERROR
INTERNAL
SERVER

An
error
has
appeared
in
the
server
due
to
some
server
internal
problem




ERROR
INVALID
DAIS
HANDLE

A
client
or
server
handle
was
invalid




ItemError

A
struct
for
reporting
of
item
related
errors




Member

Description



err

An
error
code
as
described
below




client
handle

The
client
side
handle
identifying
the
item




server
handle

The
server
side
handle
identifying
the
item




pathname

The
pathname
for
display
or
presentation
purposes




reason

An
additional
text
explaining
the
error




AccessRights

Numeric
access
rights
supported
per
item




EnumValue

Description



READABLE

Read
only
data




WRITEABLE

Write
only
data




READ
AND
WRITABLE

Both
read
and
write
data




OPCQuality

A
flag
word
giving
the
OPC
quality

Each
flag
has
a
specific
meaning
as
described
below

Four
groups
of
flags
exist




1


Main
quality
telling
if
a
value
is
good

bad

or
suspected




2


Detailed
quality




3


Limits
telling
if
the
value
is
stuck




4


Historical
data
access
flags

Those
flags
are
described
in
the
HDAIS
specification

Bit
masks
are
defined
to
extract
these
flags




Quality

status

and
limit
bit
masks



Mask

Description



OPC
QUALITY
MASK

Bit
mask
for
main
quality




OPC
STATUS
MASK

Bit
mask
for
detailed
quality




OPC
LIMIT
MASK

Bit
mask
for
the
limits




Main
quality
enumeration
numbers



Enum

Description



OPC
QUALITY
BAD

The
number
for
bad
quality




OPC
QUALITY
UNCERTAIN

The
number
for
uncertain
quality




OPC
QUALITY
GOOD

The
number
for
good
quality




After
application
of
the
OPC
QUALITY
MASK
the
quality
shall
be
compared
directly
to
the
enumeration
numbers
to
decide
the
quality


Detailed
quality
flags
for
bad
quality



Flag

Description



OPC
QUALITY
CONFIG
ERROR

There
is
a
server
configuration
error
concerning
this
value




OPC
QUALITY
NOT
CONNECTED

The
source
of
the
value
is
not
connected




OPC
QUALITY
DEVICE
FAILURE

A
device
failure
has
been
detected




OPC
QUALITY
SENSOR
FAILURE

A
sensor
failure
has
been
detected




OPC
QUALITY
LAST
KNOWN

The
updating
has
stopped
but
there
is
an
old
value
available




OPC
QUALITY
COMM
FAILURE

Communication
has
failed
and
no
value
available




OPC
QUALITY
OUT
OF
SERVICE

The
updating
of
the
value
is
manually
blocked
for
update

the
item
is
not
active





Detailed
quality
flags
for
uncertain
quality



Flag

Description



OPC
QUALITY
LAST
USABLE

The
value
is
old

The
time
stamp
gives
the
age




OPC
QUALITY
EGU
EXCEEDED

The
value
is
beyond
the
capability
of
representation

for
example

counter
overflow





OPC
QUALITY
SENSOR
CAL

The
sensor
calibration
is
bad




OPC
QUALITY
SUB
NORMAL

Value
is
derived
from
multiple
sources
where
the
majority
has
less
than
required
good
quality




DAIS
QUALITY
OCILLATORY

If
a
binary
value
changes
cyclically
with
a
frequency
higher
than
a
specific
threshold

it
is
oscillating

This
quality
compliant
with
IEC
61850-7-3




Definition
of
limit
flags



Flag

Description



OPC
LIMIT
OK

The
value
is
not
limited

that
is

it
moves
freely
up
or
down




OPC
LIMIT
LOW

The
value
is
stuck
at
a
low
limit






OPC
LIMIT
HIGH
The
value
is
stuck
at
a
high
limit

OPC
LIMIT
CONST
The
value
is
stuck
constant


DAIS
Quality
extension
masks

The
part
of
the
flag
word
giving
the
DAIS
extended
quality

Each
flag
has
a
specific
meaning
as
described
below

These
quality
definitions
are
based
on
the
revised
IEC
61850-7-3
definitions
of
quality

The
following
masks
are
defined




Mask

Description



EXQ
SOURCE
MASK

Bit
mask
for
the
source




EXQ
TEST
MASK

Bit
mask
for
the
test
status

The
test
status
indicates
that
the
value
is
generated
by
a
test
and
shall
not
be
regarded
as
an
operational
value




EXQ
OPERATOR
BLOCKED
MASK

Bit
mask
for
the
operator
blocked
status

The
status
indicates
that
the
value
has
been
blocked
for
update
and
is
old

The
OPC
QUALITY
LAST
USABLE
quality
shall
be
set
as
well




EXQ
TIMESTAMP
ACCURACY
MASK

Bit
mask
for
the
time
stamp
accuracy




Flags
defining
source



Flag

Description



EXQ
SOURCE
NONE

There
is
no
source
for
this
data
item

The
code
is
used
for
spare
items
not
yet
allocated




EXQ
SOURCE
PROCESS

The
source
for
this
value
is
the
process




EXQ

SOURCE
PRIMARY

SUBSTITUTED

The
value
is
manually
substituted




EXQ
SOURCE
INHERITED

SUBSTITUTED

A
substituted
value
has
been
copied
or
used
as
input
to
some
calculation

The
result
value
is
then
marked
with
EXQ
SOURCE
INHERITED

SUBSTITUTED




EXQ
SOURCE
CORRECTED

An
alternate
and
more
accurate
value
has
been
calculated
by
some
application

e
g


a
State
Estimator


If
this
value
has
been
used
to
correct
the
original
value

it
shall
be
indicated
EXQ
SOURCE
CORRECTED




EXQ
REMOTE
DEFAULTED

The
value
is
initialized
by
a
default
value




Flags
defining
time
stamp
quality



Flag

Description



EXQ
LOCAL
NONEEXQ
TS
ACC

10
MSEC

The
value
is
not
updated
locally

i
e


it
has
a
remote
source
specification


The
flags

=0

indicate
that
the
accuracy
is
10
milliseconds
or
better

IEC61850-7-2
performance
class
T0





EXQ
LOCAL
SUBSTITUTEDEXQ
TS

ACC
100
MSEC

The
value
is
locally
substituted

manually


The
flags

=1

indicate
that
the
accuracy
is
100
milliseconds
or
better




EXQ
LOCAL
SE
REPLACEDEXQ
TS

ACC
SECOND

The
value
is
locally
substituted
by
State
Estimator

The
flags

=2

indicate
that
the
accuracy
is
in
the
range
of
seconds
or
better




EXQ
TS
ACC
BAD
TIME

The
flags

=3

indicate
that
the
time
stamp
is
bad




QualityThe
DAIS
quality
consists
of
OPCQuality
and
ExtendedQuality



Member

Description



opc
quality

The
quality
as
specified
by
OPC
including
extensions
from
DAIS




user
quality

A
user
specific
quality











Methods
that
return
information
about
more
than
one
resource
may
return
an
iterator

The
resource
description
iterator
allows
a
client
to
access
a
large
query
result
sequentially

several
resources
at
a
time

This
is
necessary
where
the
ORB
limits
message
sizes

It
also
enables
implementations
to
overlap
the
client
and
server
processing
of
query
results

if
necessary



The
client
and
the
data
provider
should
cooperate
to
manage
the
lifetime
of
the
iterator
and
the
resources
it
consumes

The
destroy


and
next
n


methods
allow
the
client
and
data
provider
respectively
to
indicate
that
the
iterator
may
be
destroyed



In
addition

the
data
provider
may
autonomously
destroy
the
iterator
at
any
time

for
resource
management
or
other
reasons


If
a
client
detects
that
an
iterator
has
been
destroyed

it
will
not
interpret
this
condition
in
itself
as
either
an
indication
that
the
end
of
the
iteration
has
been
reached

or
as
a
permanent
failure
of
the
data
provider


next
n



This
operation
returns
possibly
0
and
at
most
n
resource
descriptions
in
the
form
of
a
resource
description
sequence

In
all
cases
the
state
of
the
iteration
is
indicated
by
the
Boolean
return
value




•	
True
means
that
there
may
be
more
resource
descriptions
beyond
those
returned
so
far




•	
False
means
all
the
resource
descriptions
have
now
been
returned

No
further
calls
are
expected
for
this
iterator
and
the
data
provider
may
destroy
the
iterator
at
any
time
after
the
call
returns




reset



This
operation
resets
the
iterator
to
the
first
element


clone



This
operation
returns
a
copy
of
the
iterator


destroy



This
operation
is
used
to
terminate
iteration
before
all
the
resource
descriptions
have
been
returned

After
destroy


is
invoked
no
further
calls
are
expected
for
this
iterator


The
data
provider
may
destroy
the
iterator
at
any
time
after
the
call
returns














A
node
may
represent
a
real
world
object
such
as
a
location
or
a
piece
of
equipment

A
node
may
also
represent
a
schema
item
such
as
a
type
or
property

Nodes
correspond
to
“branches?
in
the
IOPCBrowseServerAddressSpace
or
IOPCEventAreaBrowser
interfaces

Nodes
correspond
to
Resources
in
the
RDF
model
and
the
DAF
interface

Each
node
has
a
universal
identity
given
by
its
ResourceID

The
ResourceID
of
a
node
is
the
same
in
all
views
provided
by
a
DAIS
server

DAIS
servers
may
be
coordinated
with
DAF
servers
so
that
a
node
has
the
same
ResourceID
as
the
corresponding
resource

Each
node
has
zero
or
more
child
s


A
child
may
be
another
node
or
any
other
type
of
object

for
example

data
access
items
or
alarms
&
event
sources


Each
node
has
a
type

The
type
determines
what
other
types
of
child
objects
a
node
has


Nodes
are
arranged
in
a
strict
hierarchy
for
naming
purposes

A
DAIS
server
may
provide
more
than
one
such
hierarchy

each
is
called
a
view


The
view
is
selected
when
the
session
is
initiated


Within
a
view

each
node

except
for
the
root
node

has
a
single
parent
node

a
label
that
is
unique
among
all
nodes
with
the
same
parent

and
a
unique
pathname

A
node’s
pathname
is
a
string
that
contains
its
label
and
the
pathname
of
its
parent

The
pathname
must
be
a
valid
URI

but
apart
from
that
the
syntax
of
pathnames
is
implementation
dependent


The
Node
IDL
defines
a
main
interface
DAIS

Node

IHome
for
browsing
among
the
hierarchically
structured
nodes

Nodes
are
described
by
DAIS

Node

Description
struct




DAIS

Node

Iterator
max
left


next
n


reset


clone


destroy


<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids


<<Interface>>
0

n
1
0

n1Node
id


ResourceID
label


string
type


ResourceID
0

n0
1

n1NodeItemComponent
pathname


string
1
0

*
+parent
10

*
Figure
3-2
DAIS
node
IDL
in
UML










File

DAISNode
idl
#ifndef

DAIS
NODE
IDL
#define

DAIS
NODE
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
Node
{

struct
Description



{





ResourceID

id





ResourceID

parent





string

label





string

descrip





ResourceID

type





boolean

is
leaf




}






typedef
sequence<
Description
>
Descriptions


interface
Iterator
{
boolean
next
n






in

unsigned
long

n





out

Descriptions

nodes












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownResourceID
{string
reason
}

exception
InvalidFilter
{string
reason
}

exception
UnkownTypeID
{string
reason
}


Description
find


in
ResourceID
node


raises

UnknownResourceID



Descriptions
find
each


in
ResourceIDs
nodes


raises

UnknownResourceID



Iterator
find
by
parent


in
ResourceID
node

in
string
filter
criteria



raises

UnknownResourceID

InvalidFilter



Iterator
find
by
type


in
ResourceID
node

in
string
filter
criteria

in
ResourceIDs
type
filter



raises

UnknownResourceID

InvalidFilter

UnknownTypeID



Strings
get
pathnames


in
ResourceIDs
nodes




ResourceIDs
get
ids


in
Strings
pathnames




}
}
}

#endif




DAIS
NODE
IDL

Description

A
struct
describing
a
node




Member

Description



id

The
identification
of
this
node




parent

The
identification
of
the
parent
node




label

The
label

single
level
designation

of
the
node




descrip

A
descriptive
text
for
the
node




type

A
reference
to
the
type
of
the
node




is
leaf

Indicate
if
the
node
is
a
leaf

i
e


it
has
no
child
nodes





Iterator


Refer
to
Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10

This
interface
corresponds

to
the
OPC
interface
EnumString
with
the
difference
that
the
Iterator
returns
the
Description
struct
instead
of
a
string


IHome

An
interface
used
for
browsing
nodes

The
interface
corresponds
to
the
IOPCBrowseServerAddressSpace
with
the
BrowseFilterType
set
to
OPC
BRANCH
or
the
IOPCEventAreaBrowser

A
major
difference
to
OPC
is
that
the
server
does
not
provide
a
cursor
for
clients

Instead
clients
have
to
provide
the
browse
position
in
each
call


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

For
methods
taking
a
sequence
of
resource
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


InvalidFilter

An
exception
telling
the
filter
criteria
string
is
not
correct

The
likely
reason
behind
this
exception
is
an
erroneously
entered
string


UnknownTypeID

An
exception
telling
one
or
more
TypeIDs
does
not
exist


find



For
a
given
node

return
information
about
that
node




Parameter

Description



node

A
node
identification




return

The
node
description




find
each




For
a
sequence
of
nodes

return
information
about
each
node




Parameter

Description



nodes

A
sequence
of
node
identifications




return

An
iterator
holding
the
node
descriptions




find
by
parent




For
a
given
node

return
all
child
nodes
at
that
node

Hence
to
reach
leaf
nodes
using
this
method
repeated
calls
must
be
made
for
each
level

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
BRANCH





Parameter

Description



node

The
parent
node
identification




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
nodes
with
a
pathname
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





return

An
iterator
holding
the
child
node
descriptions




find
by
type



For
a
sub-tree
given
by
the
node
parameter

return
all
child
nodes
of
the
specified
type

This
will
return
all
leaf
nodes
under
the
given
sub-tree
root
node

There
is
no

corresponding
operation
in
OPC

Refer
to
Section
4
2
4
1

“DAIS

Item
Overview
?
on

page
4-15
for
a
description
of
how
item
browsing
is
mapped
to
OPC





Parameter
Description
node
The
identification
of
the
node
defining
the
sub-tree




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
nodes
with
a
pathname
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





type
filter

A
list
of
TypeIDs

Nodes
matching
any
of
the
TypeIDs
will
be
held
by
the
returned
iterator




return

An
iterator
holding
descriptions
for
the
found
nodes




get
pathnames



Translate
a
sequence
of
node
identifications
to
the
corresponding
sequence
of
pathnames

If
a
node
fails
to
translate
to
a
pathname

due
to
an
unknown
node
identification


the
corresponding
pathname
is
an
empty
string




Parameter

Description



nodes

The
sequence
of
nodes




return

The
corresponding
sequence
of
pathnames




get
ids



Translate
a
sequence
of
pathnames
to
the
corresponding
sequence
of
node
identifications

If
a
pathname
fails
to
translate
to
a
node
identification

due
to
an
unrecognized
pathname


the
corresponding
node
identification
is
NULL




Parameter

Description



pathnames

The
sequence
of
pathnames




return

The
corresponding
sequence
of
node
identifications


















A
type
represents
a
set
of
related
properties
and
associations

Each
node
has
a
type
and
all
the
properties
represented
by
that
type
apply
to
the
node

Each
type
is
identified
by
a
ResourceID
and
has
a
label
and
description

A
type
may
be
obtained
for
any
node
using
the
node’s
TypeID

Related
types
may
be
grouped
into
a
schema

A
ResourceID
identifies
each
schema

All
the
types
in
a
schema
may
be
obtained
given
the
schema
ResourceID

A
schema
and
its
type
may
be
represented
as
nodes
in
one
or
more
of
views
provided
by
a
DAIS
server

When
a
schema
is
represented
as
a
node

the
node’s
ResourceID
and
the
schema
ResourceID
are
identical

Similarly

when
a
type
is
represented
as
a
node

the
node’s
ResourceID
and
the
type’s
ResourceID
are
identical

The
type’s
parent
is
always
the
node
representing
its
schema

the
type’s
label
is
identical
to
the
node
label
and
the
type’s
description
is
identical
to
the
node
description


The
type
IDL
defines
a
main
interface
DAIS

Type

IHome
for
browsing
supported
types




DAIS

Type

IHome
find


find
by
schema


<<Interface>>

+aggregated
types


11


0

n0

n



0

n0

n


11


0

n0

n



Type
id


ResourceID
schema


ResourceID
label


string
description


string



DAIS

Type

Iterator
max
left


next
n


destroy


<<Interface>>






Figure
3-3
DAIS
type
IDL
in
UML







File
DAISType
idl



#ifndef

DAIS
TYPE
IDL



#define

DAIS
TYPE
IDL



#pragma
prefix
"omg
org"



#include
"DAISCommon
idl"



module
DAIS
{



module
Type
{



struct
Description
{



ResourceID

id




ResourceID

schema




string

label




string

descrip




ResourceIDs

aggregated
types




}





typedef
sequence<Description>

Descriptions




interface
Iterator




{




boolean
next
n






in
unsigned
long

n




out
Descriptions

types










void
reset


Iterator
clone


void
destroy



}


interface
IHome
{
exception
UnknownResourceID
{string
reason
}


Description
find

in
ResourceID
type

raises

UnknownResourceID


Iterator
find
by
schema


in
ResourceID
schema



raises

UnknownResourceID


}
}
}

#endif




DAIS
TYPE
IDL

Description

A
struct
describing
a

type




Member

Description



id

The
identification
of
this
type




schema

The
identification
of
the
schema
where
the
type
is
defined




label

The
label
of
the
type




descrip

A
description
of
the
type




aggregated
types

A
sequence
of
type
identifications
that
a
node
of
this
type
may
contain

This
information
is
intended
as
a
guide
when
the
type
filter
is
specified
for
the
find
by
type


methods




IHome

An
object
used
to
browse
the
types

There
is
no
corresponding
interface
in
OPC


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find



For
a
given
type

return
information
about
that
type




Parameter

Description



type

A
type
identification




return

The
type
description




find
by
schema



For
a
given
schema

find
all
types
defined
by
that
schema




Parameter

Description



schema

The
identification
of
the
schema




return

A
sequence
of
type
descriptions


















A
property
represents
a
characteristic
of
a
node
that
can
be
described
with
a
value

A
given
property
may
apply
to
many
nodes

for
each
such
node
there
will
be
an
item

corresponding
to
the
property


See
Section
4
2
4

“DAISItem
IDL
?
on
page
4-15




A
DAIS
property
corresponds
to
a
property
in
RDF
and
the
DAF

A
DAIS
property
corresponds
to
the
concept
of
a
property
in
OPC
accessed
with
the
IOPCItemProperties

QueryAvailableProperties


method

However

the
six
core
OPC
properties

timestamp

quality

value

do
not
correspond
to
properties
in
DAIS

They
are
given
special
treatment
in
OPC

they
are
not
the
same
as
other
OPC
properties


See

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15
for
interfaces
to
handle
these



Each
property
is
identified
by
a
ResourceID
and
has
a
label

description

and
canonical
data
type

The
canonical
data
type
is
a
member
of
the
SimpleType
enumeration
and
indicates
the
preferred
CORBA
atomic
data
type
for
values
of
this
property

Every
item
of
a
given
property
has
an
identical
canonical
data
type

A
property
may
be
obtained
for
any
item
via
the
property
member
of
the
ItemID

All
properties
that
apply
to
a
given
node
may
be
obtained

given
the
node’s
ResourceID

All
properties
that
apply
to
the
nodes
of
a
given
type
may
be
obtained

given
the
TypeID

A
property
may
be
represented
as
a
node
in
one
or
more
of
views
provided
by
a
DAIS
server

In
this
case
the
node’s
ResourceID
and
the
property’s
ResourceID
are
identical

The
property’s
parent
is
always
the
node
representing
the
type
to
which
it
belongs

The
property’s
label
is
identical
to
the
node
label
and
the
property’s
description
is
identical
to
the
node
description


The
property
IDL
defines
a
main
interface
DAIS

Property

IHome
for
browsing
properties

The
information
model
describing
how
the
properties
are
related
to
nodes
and
items
is
found

in
Section
4
1
1

“Nodes

Items

Types

and
Properties
?
on
page
4-2





Property
id


PropertyID
label


string
description


string
canonical
data
type


SimpleValueType
DAIS

Property

IHome
<<Interface>>
find


find
each


find
by
node


find
by
type


0

n
1
0

n1
Figure
3-4
DAIS
property
IDL
in
UML










File

DAISProperty
idl#ifndef

DAIS
PROPERTY
IDL#define

DAIS
PROPERTY
IDL#pragma
prefix
"omg
org"#include
<DAISCommon
idl>
module
DAIS
{module
Property
{
struct
Description
{
PropertyID
id

string
label

string
descrip

SimpleValueType
canonical
data
type


}
typedef
sequence<Description>
Descriptions

interface
IHome
{
exception
UnknownResourceID
{string
reason
}


Description
find


in
PropertyID
property


raises

UnknownResourceID



Descriptions
find
each


in
PropertyIDs
properties


raises

UnknownResourceID



Descriptions
find
by
node


in
ResourceID
node


raises

UnknownResourceID



Descriptions
find
by
type


in
ResourceID
type



raises

UnknownResourceID


}
}
}

#endif




DAIS
PROPERTY
IDL

Description

Describe
a
property




Member

Description



id

The
identification
of
this
property




label

The
label

single
level
designation

of
the
property




descrip

A
description
of
the
property




canonical
data
type

The
data
type
used
for
the
property
in
the
server




Home

An
object
used
for
browsing
properties
defined
for
a
type
or
existing
at
a
node

It
corresponds
to
the
OPC
interface
IOPCItemProperties


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find



For
a
given
property

return
information
about
that
property




Parameter

Description



property

A
property
identification




return

The
property
description




find
each



For
a
given
property

return
information
about
that
property




Parameter

Description



properties

A
sequence
of
property
identifications




return

The
sequence
of
property
descriptions




find
by
node




For
a
node

return
information
about
each
property
describing
its
items

This
method
corresponds
to
IOPCItemProperties

QueryAvailableProperties






Parameter

Description



node

A
node
identification




return

A
sequence
of
property
descriptions




find
by
type




For
a
given
type

return
all
property
descriptions




Parameter

Description



type

A
type
identification




return

A
sequence
of
property
descriptions


















The
session
is
an
interface
inherited
by
data
access
and
alarms
&
events
sessions

A
session
represents
a
single
conversation
with
the
DAIS
service

A
session
has
a
connection
to
a
shut
down
callback
used
by
a
server
to
shut
down
clients
in
the
case
of
an
ordered
shut
down
of
the
server

If
the
session
object
is
destroyed
or
a
failure
is
detected
by
the
server
when
invoking
an
operation
on
any
callback
objects

then
the
session
is
terminated


A
session
object
corresponds
to
the
OPC
server
object

hence
each
OPC
server
object
will
be
represented
by
a
session
object
in
DAIS




Client

fro
m
DA
ISServ
er

DAIS

ShutdownCallback
<<Interface>>
shutdown
notify


1
0

1
10

1DAIS

Session
<<Interface>>
status




DAIS

SessionStatus
callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy


0

1
1
0

11
Figure
3-5
DAIS
session
IDL
in
UML

The
status


method
corresponds
to
the
read
only
SessionStatus
attribute
in
the
IDL

The
callback


get
and
set
methods
correspond
to
the
ShutDownCallback
attribute











File
DAISSession
idl
#ifndef

DAIS
SESSION
IDL
#define

DAIS
SESSION
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{

struct
SessionStatus
{
string
name

DateTime
start
time

DateTime
current
time

DateTime
last
update
time

unsigned
long
group
count

long
band
width


}


interface
ShutdownCallback
{

void
shutdown
notify







in
string

reason












}







interface
Session
{

readonly
attribute
SessionStatusstatus


attribute
ShutdownCallback
callback


void
destroy



}
}

#endif




DAIS
SESSION
IDL

SessionStatus

A
struct
holding
session
status




Parameter

Description



name

Within
the
server
unique
name
of
the
session




start
time

The
time
when
the
session
was
started

This
time
is
not
reset
during
the
session
lifetime




current
time

The
current
time
as
known
by
the
server




last
update
time

The
time
when
the
server
sent
an
event
notification
for
this
session




group
count

The
current
number
of
groups
for
a
data
access
session
or
the
number
of
event
subscriptions
for
an
alarms
&
event
session




band
width

If
held
updated
by
the
server
the
percentage
bandwidth
in
use
for
communication
with
underlying
RTUs
or
devices

A
value
of
100
or
more
indicates
that
more
bandwidth
for
communication
with
devices
is
required
than
available

A
value
of
-1
indicates
the
value
is
unknown
by
the
server




ShutdownCallback

An
object
implemented
by
clients
and
used
by
the
server
to
indicate
that
it
will
shutdown
soon

No
further
calls
should
be
made
and
no
further
data
callbacks
should
be
expected


shutdown
notify





Parameter
Description
reason
An
explanation
of
why
the
server
is
shutting
down


Session

An
interface
representing
a
single
conversation
with
the
DAIS
service

The
interface
is
inherited
into
interfaces
representing
sessions
supporting
specific
services


for
example

data
access
or
alarms
&
events



status
A
read
only
attribute
holding
the
SessionStatus

callback
An
attribute
holding
a
reference
to
a
ShutDownCallback
object

A
client
that
wants
to

receive
shut
down
callbacks
from
a
server
shall
update
the
attribute
with
a
reference
to
a
ShutDownCallback
object


destroy



A
method
for
deletion
of
the
session
object











Some
methods
have
a
filter
string

for
example

the
browse
methods
find
by
type


and
find
by
parent


in
DAISNode
and
DAISItem


The
filter
string
shall
contain
a
pattern
that
is
used
to
match
a
text
string

e
g


the
pathname


The
text
strings
matching
the
pattern
are
passing
the
filter


The
strings
that
may
appear
in
the
filter
string
pattern
are
listed
below




Characters
in
pattern

Matches
in
string



?

Any
single
character




*

Zero
or
more
characters




#

Any
single
digit

0-9





substring

The
specified
substring



[charlist]

Any
single
character
in
charlist




[!charlist]

Any
single
character
not
in
charlist




Some
examples
of
patterns
and
strings
are
given
below




Pattern

String

String
pass
filter



a*a

aBBBa

Yes



[A-Z]

F

Yes



[!A-Z]

F

No



a#a

a2a

Yes



a[L-P]#[!c-e]

aM5b

Yes



B?T*

BAT123khg

Yes



B?T*

CAT123khg

No










This
section
defines
a
little
language
that
is
used
to
describe
logical
expressions
and
navigation
in
structures

A
logical
expression
evaluates
to
true
or
false
and
can
be
used
in
filters
for
collection
of
data
or
definition
of
states

etc

The
condition
logic
described
in

Section
5
2
7

“DAISConditionSpace
IDL
?
on
page
5-32
is
used
to
define
states



In
DAIS
the
data
model
seen
through
the
API
is
a
hierarchical
structure
of
typed
nodes

A
typed
node
may
contain
other
typed
nodes
and
or
property
values

called
items


This

data
model
is
described
in
more
detail
in
Section
4
1

“Information
Model
?
on
page
4-1


In
addition
to
this
hierarchy
DAIS
supports
data
models
where
a
property
value
may
refer
to
one
or
more
other
nodes

Hence
navigation
via
such
references
is
needed
as
well

An
information
model
that
includes
both
hierarchy
and
references
is
the
IEC
61970

briefly
described
in
Section
4
1
5

“Utility
SCADA
EMS
Measurement
Model
?
on

page
4-5



To
be
able
to
navigate
to
nodes
in
the
structure
the
little
language
shall
include
support
for
describing
paths

XML
Path
Language

XPath

[13]
is
a
language
that
supports
navigation
in
structures
and
this
specification
uses
a
subset
of
XPath
as
the
logical
expression
language

XPath
requires
the
exposed
data
model
to
be
hierarchical

even
though
a
model
is
exposed
as
hierarchical
it
may
internally
be
organized
in
other
ways



A
logical
expression
in
XPath
is
called
“PredicateExpr?

statement
9
in
the
XPath
specification
[13]


A
PredicateExpr
evaluates
to
true
or
false

A
logical
expression
in
DAIS
is
called
DAIS
Expression

The
rules
for
a
DAIS
expression
are





•	
DAIS
Expression


=
PredicateExpr


The
following
restrictions
of
the
functionality
described
in
the
XPath
specification
are
defined
for
DAIS
Expression




•	
The
union
operator
"|"
is
not
supported

refer
to
statement
18
in
[13]




•	
The
arithmetic
operators
"+"

"-"

"div"

"*"
and
"mod"
are
not
supported

refer
to
statements
25

26
and
27
in
[13]




•	
unabbreviated
location
paths
is
not
supported




•	
abbreviated
location
paths
is
supported




•	
the
following
axes
are
supported

child

parent

descendant

attribute

and
self




•	
the
following
XPath
functions
are
supported

id



position



not



true



false






The
mapping
between
DAIS
and
XML
data
models
is
listed
below


Table
3-1
Mapping
between
DAIS
and
XML
data
models



DAIS
entity

XML
entity

Comment



Node

A
DAIS
Node
element
that
may
be
contained
by
another
DAIS
node
element


The
DAIS
Node
element
name
is
the
DAIS

Type
name

DAIS

Type

Description
label

referenced
by
DAIS

Node

Description
type

If
the
DAIS
Node
element
has
a
parent
element

the
parent
is
given
by
Node

Description
parent




Node

Description
id

An
id
attribute
of
type
ID
at
a
DAIS
Node
element


Accessed
by
the
id


function



Node

Description
label

A
child
element
of
a
DAIS
Node
element


The
element
name
is
“label
?
The
value
is
Node

Description
label




Table
3-1
Mapping
between
DAIS
and
XML
data
models



DAIS
entity

XML
entity

Comment



Node

Description

descrip

A
child
element
of
a
DAIS
Node
element


The
element
name
is
“description
?
The
value
is
Node

Description
descrip




Item

A
DAIS
Item
element
that
is
child
of
a
DAIS
Node
element


The
element
name
is
the
DAIS

Property
name

DAIS

Property


Description
label

concatenated
with
the
DAIS
Node
element
name
separated
by
a
“
?

The
DAIS

Property
is
given
by
Item

Description
id
property

The
DAIS
Node
parent
element
is
given
by
Item

Description
id
resource




Item

Description
value

The
value
of
the
DAIS
Item
element





XML
data
example

<MeasurementModel>

<Measurement
id="
100">
<label>M100<
label>
<description
>
<Measurement
LimitSets>
200<
Measurement
LimitSets>
<MeasurementValue
id="
500">

<label>TM100<
label><description
><MeasurementValue
value>30<
MeasurementValue
value>
<MeasurementValue
MeasurementValueSource>
400
<
MeasurementValue
MeasurementValueSource>
<
MeasurementValue>

<
Measurement>

<LimitSet
id="
200"><label>summer<
label><description
><Limit
id="
300">
<label>highalarm<
label>
<description
>
<Limit
value>50<
Limit
value>

<
Limit>

<Limit
id="
301">
<label>lowalarm<
label>
<description
>
<Limit
value>-50<
Limit
value>

<
Limit>
<
LimitSet>
<MeasurementValueSource
id="
400">

<label>telemetry<
label>

<description
>

<
MeasurementValueSource>

<
MeasurementModel>


The
XML
data
example
is
based
on
the
UML
schema
in
Figure
4-3
on
page
4-6
and
the



mapping
from
Table
3-1










Through
DAIS
an
operator
gets
access
to
data
in
a
control
system

The
operator
can




•

Read
data

Data
Access

and
alarms
and
events

Alarms
&
Events





•

Write
data


Data
Access




•

Acknowledge
alarms

Alarms
&
Events





Many
control
systems
implement
an
authorization
scheme
where
it
checks
if
an
operator
is
allowed
to
read

write

or
acknowledge


A
DAIS
server
exposes
many
data
objects

If
authorization
is
supported

checks
must
be
made
by
the
server

The
server
must
then
know
who
the
operator
is

An
interface
that
can
be
used
by
the
server
to
get
this
information
is
described
in
the
Security
Service
Specification
[14]

The
Security
Service
Specification
includes
a
rich
interface
supporting
extensive
security
comprising




•

Identification
and
authentication



•

Authorization
and
access
control



•

Security
auditing



•

Security
of
communication



•

Non-repudiation



•

Administration



The
smallest
need
for
a
DAIS
server
is
to
be
able
to
identify
an
operator

a
principal
in
Security
language

so
that
access
control
can
be
made
from
within
the
DAIS
server

Authentication
is
assumed
taken
care
of
at
the
operating
system
login

The
control
of
access
to
a
DAIS
server
itself
within
the
scope
of
a
secure
system
is
not
necessarily
a
requirement

The
other
functions

auditing

secure
communication

non-repudiation

and
administration

supported
by
the
Security
Service
are
not
necessarily
required
for
a
DAIS
server









For
a
DAIS
server
the
following
requirement
levels
for
support
by
the
system
are
defined


0
-	No
authorization
and
no
requirements


1
-	Identification
of
principal
requiring
SecurityLevel1
interfaces

refer
to

[14]
appendix
A


2
-
	Security
levels
as
described
in
[14]
appendix
C

mainly
Security
Functionality
Level
1















The
DAISServer
IDL
describes
the
DAIS
server
interface
and
depends
on
the
types
of
session
interfaces

for
example

data
access
or
alarms
&
events

it
implements

A
server
not
implementing
a
session
type

data
access
or
alarms
&
events

shall
still
be
capable
of

reporting
the
type
as
not
implemented

The
IDL
files
and
dependencies
in
Figure
3-6
are

defined
below




DAISServer
DAISDASession

from
Data
Access

DAISAES
ession

from
EventAndAlarm
s

DAISSession

from
Com
m
on


Figure
3-6
Dependencies
between
server
IDL
files















The
fundamental
DAIS
service
from
which
session
objects
may
be
obtained

DAIS

Server
would
normally
be
implemented
as
a
persistent
object
accessed
via
the
naming
service
or
the
trader
service

From
the
DAIS

Server
object

the
session
objects
for
data
access
or
alarms
&
events
are
created

A
client
may
create
as
many
session
objects
as
wanted


A
session
can
be
created
for
a
view

A
view
corresponds
to
a
specific
hierarchical
organization
of
objects

also
called
nodes
in
this
specification


The
same
object
may
appear
in
multiple
views
and
hence
in
different
hierarchical
structures

An
example
is
a
breaker
appearing
in
a
functional
structure

having
the
function
of
breaking
current

and
in
a
location
structure

the
place
where
it
is
located


refer
also
to
[10]

Another
example
is
the
same
object
appearing
in
different
areas
of
authority


A
DAIS
server
supporting
data
access
may
have
a
number
of
persistent
public
groups

Public
groups
can
be
used
and
managed
through
the
group
interface

refer
to

Section
4
2
7

“DAISGroup
IDL
?
on
page
4-40


Services
that
are
not
implemented
will
raise
the
CORBA
standard
exception
NO
IMPLEMENT

Not
implemented
exceptions
can
be
expected
for
a
data
accesssession

an
alarms
&
event
session

and
inspection



DAIS

AlarmsAndEvents

Session

from
DAISAESession


<<Interface>>
DAIS

Server
<<Interface>>
status




DAISServerStatus
create
data
access
session


create
data
access
session
for
view


11create
alarms
and
events
session


create
alarms
and
events
session
for
view


find
views


110

0
n
1
n
111
0



n
n

0




Client



0

n0

n



PublicGroup
id


ResourceID
status


DAIS

DataAccess

Group

State



0

n0

n11


0

0
n
n



DAIS

DataAccess

Session

fro
m
DA
IS
DA
Session

<<Interface>>



GroupEntry

from
DAISG
roupEntry


Figure
3-7
DAIS
server
IDL
in
UML











File

DAISServer
idl#ifndef

DAIS
SERVER
IDL#define

DAIS
SERVER
IDL#pragma
prefix
"omg
org"#include
<DAISDASession
idl>#include
<DAISAESession
idl>
module
DAIS
{

enum
ServerState
{SERVER
STATE
RUNNING
SERVER
STATE
FAILED
SERVER
STATE
NOCONFIG
SERVER
STATE
SUSPENDED
SERVER
STATE
TEST
}


struct
ServerStatus
{
DateTime
start
time

DateTime
current
time

ServerState
server
state

unsigned
long
session
count

unsigned
long
major
version

unsigned
long
minor
version

unsigned
long
build
number

string
vendor
info


}


interface
Inspection
{}


interface
Server

{
exception
DuplicateName
{string
reason
}

exception
InvalidView
{string
reason
}


readonly
attribute
ServerStatusstatus
readonly
attribute
SupportedFunctions
supported
functions

DataAccess

Session
create
data
access
session
in
string
session
name

raises

DuplicateName


DataAccess

Session
create
data
access
session
for
view

in
string
session
name

in
string
view
name



raises

DuplicateName

InvalidView



AlarmsAndEvents

Session
create
alarms
and
events
session

in
string
session
name


raises

DuplicateName



AlarmsAndEvents

Session

create
alarms
and
events
session
for
view

in
string
session
name

in
string
view
name


raises

DuplicateName

InvalidView



Strings
find
views




Inspection
inspect




}
}


#endif




DAIS
SERVER
IDL

ServerState

An
enumeration
of
the
states
a
Server
may
have




EnumValue

Description



SERVER
STATE
RUNNING

The
server
is
running
normally

This
is
the
usual
state
for
a
server




SERVER
STATE
FAILED

A
vendor
specific
fatal
error
has
occurred
within
the
server

The
server
is
no
longer
functioning

The
recovery
procedure
from
this
situation
is
vendor
specific




SERVER
STATE
NOCONFIG

The
server
is
running
but
has
no
configuration
information
loaded
and
thus
cannot
function
normally

This
state
implies
that
the
server
needs
configuration
information
in
order
to
function

Servers
that
do
not
require
configuration
information
should
not
return
this
state




SERVER
STATE
SUSPENDED

The
server
has
been
temporarily
suspended
via
some
vendor
specific
method
and
is
not
getting
or
sending
data

Note
that
Quality
will
be
returned
as
OPC
QUALITY
OUT
OF
SERVICE




SERVER
STATE
TEST

The
server
is
in
Test
Mode

The
outputs
are
disconnected
from
the
real
hardware
but
the
server
will
otherwise
behave
normally

Inputs
may
be
real
or
may
be
simulated
depending
on
the
vendor
implementation

Quality
will
generally
be
returned
normally




ServerStatus



Member

Description



start
time

Time
the
server
was
started

This
is
constant
for
the
server
instance
and
is
not
reset
when
the
server
changes
states

Each
instance
of
a
server
should
keep
the
time
when
the
process
started




current
time

The
current
time
as
known
by
the
server




server
state

The
current
status
of
the
server

Refer
to
ServerState
enumeration




session
count

The
total
number
of
sessions
created
by
clients
for
this
server




major
version

The
major
version
of
the
server
software






minor
version

The
minor
version
of
the
server
software




build
number

The
‘build
number’
of
the
server
software




vendor
info

Vendor
specific
string
providing
additional
information
about
the
server

It
is
recommended
that
this
mention
the
name
of
the
company
and
the
type
of
device
s

supported




supported
functions

A
constant
that
tells
what
functions
are
implemented
by
the
DAIS
server

e
g


Data
Access

Alarms
&
Events
or
both



Inspection

An
optional
interface
intended
to
be
specialized
into
a
vendor
specific
inspection
object

The
inspection
object
is
intended
to
expose
server
internal
details
for
debugging
and
inspection
purposes


Server

An
object
implementing
the
DAIS
server

A
DAIS
server
might
provide
more
than
one
view
on
nodes

A
view
is
a
specific
hierarchical
organization
of
nodes
and
nodes
may
appear
in
more
than
one
hierarchical
structure

for
example

a
functional
structure
or
a

location
structure
as
defined
by
IEC
1346-1


refer
also
to
Section
2
4

“IEC
1346-1


Structuring
and
Naming
?
on
page
2-7



DuplicateName

An
exception
raised
when
an
object
is
created
and
the
name
already
exists

No
object
is
created
if
the
exception
is
raised

Is
used
for
session
and
group
manager
objects


InvalidView

An
exception
raised
when
an
invalid
view
is
specified

An
invalid
view
is
if
the
view
name
does
not
exist
or
a
view
not
intended
for
the
type
of
session
is
used

for
example

a
view
for
data
access
is
used
for
alarms
&
events



statusAn
attribute
holding
the
ServerStatus
create
data
access
session


A
method
for
creation
of
a
data
access
session
object

The
default
view
will
be
used




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
data
access
session
for
view



A
method
for
creation
of
a
data
access
session
object
using
a
view
of
nodes




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




view
name

The
name
of
the
view
to
open

If
no
name
is
supplied

the
default
view
will
be
used




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
alarms
and
events
session



A
method
for
creation
of
an
alarms
&
events
session
object

The
default
view
will
be
used




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
alarms
and
events
session
for
view



A
method
for
creation
of
an
alarms
&
events
session
object
using
a
view
of
areas

This
allows
a
server
to
support
different
area
structures
for
different
purposes

for
example

operational
responsibility

workorder
management





Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




view
name

The
name
of
the
view
to
open




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




find
views



A
method
to
get
the
names
for
the
server
supported
views




Parameter
Description
return
A
sequence
of
view
names


inspect



A
method
for
creation
of
an
inspection
object




Parameter
Description
return
The
inspection
object


Session
Management





Client

Client


DAIS

Server
DAIS

ServerDataAccess


DAIS

DataAccess

Session
DataAccess


DAIS

DataAccess

SessionA&E

A&EDAIS

AlarmsAndEvents

SessionD

AIS

AlarmsAndEvents

SessionCreate
a
data
access
session
for
a
specific
structure
and
do
work

e
g

create
groups
and
subscribe
find
views



create
alarms
and
events
session



Do
work
with
alarms
&
events
session
e
g

create
an
AESubscription
create
data
access
session
for
view



Get
the
available
views
destroy



destroy




Figure
3-8
Session
management
interaction






The
DAISServer
IDL
describes
the
DAIS
server
interface
and
depends
on
the
types
of
session
interfaces

for
example

data
access
or
alarms
&
events

it
implements

A
server
not
implementing
a
session
type

data
access
or
alarms
&
events

shall
still
be
capable
of

reporting
the
type
as
not
implemented

The
IDL
files
and
dependencies
in
Figure
3-6
are

defined
below




DAISServer
DAISDASession

from
Data
Access

DAISAES
ession

from
EventAndAlarm
s

DAISSession

from
Com
m
on


Figure
3-6
Dependencies
between
server
IDL
files













The
fundamental
DAIS
service
from
which
session
objects
may
be
obtained

DAIS

Server
would
normally
be
implemented
as
a
persistent
object
accessed
via
the
naming
service
or
the
trader
service

From
the
DAIS

Server
object

the
session
objects
for
data
access
or
alarms
&
events
are
created

A
client
may
create
as
many
session
objects
as
wanted


A
session
can
be
created
for
a
view

A
view
corresponds
to
a
specific
hierarchical
organization
of
objects

also
called
nodes
in
this
specification


The
same
object
may
appear
in
multiple
views
and
hence
in
different
hierarchical
structures

An
example
is
a
breaker
appearing
in
a
functional
structure

having
the
function
of
breaking
current

and
in
a
location
structure

the
place
where
it
is
located


refer
also
to
[10]

Another
example
is
the
same
object
appearing
in
different
areas
of
authority


A
DAIS
server
supporting
data
access
may
have
a
number
of
persistent
public
groups

Public
groups
can
be
used
and
managed
through
the
group
interface

refer
to

Section
4
2
7

“DAISGroup
IDL
?
on
page
4-40


Services
that
are
not
implemented
will
raise
the
CORBA
standard
exception
NO
IMPLEMENT

Not
implemented
exceptions
can
be
expected
for
a
data
accesssession

an
alarms
&
event
session

and
inspection



DAIS

AlarmsAndEvents

Session

from
DAISAESession


<<Interface>>
DAIS

Server
<<Interface>>
status




DAISServerStatus
create
data
access
session


create
data
access
session
for
view


11create
alarms
and
events
session


create
alarms
and
events
session
for
view


find
views


110

0
n
1
n
111
0



n
n

0




Client



0

n0

n



PublicGroup
id


ResourceID
status


DAIS

DataAccess

Group

State



0

n0

n11


0

0
n
n



DAIS

DataAccess

Session

fro
m
DA
IS
DA
Session

<<Interface>>



GroupEntry

from
DAISG
roupEntry


Figure
3-7
DAIS
server
IDL
in
UML










File

DAISServer
idl#ifndef

DAIS
SERVER
IDL#define

DAIS
SERVER
IDL#pragma
prefix
"omg
org"#include
<DAISDASession
idl>#include
<DAISAESession
idl>
module
DAIS
{

enum
ServerState
{SERVER
STATE
RUNNING
SERVER
STATE
FAILED
SERVER
STATE
NOCONFIG
SERVER
STATE
SUSPENDED
SERVER
STATE
TEST
}


struct
ServerStatus
{
DateTime
start
time

DateTime
current
time

ServerState
server
state

unsigned
long
session
count

unsigned
long
major
version

unsigned
long
minor
version

unsigned
long
build
number

string
vendor
info


}


interface
Inspection
{}


interface
Server

{
exception
DuplicateName
{string
reason
}

exception
InvalidView
{string
reason
}


readonly
attribute
ServerStatusstatus
readonly
attribute
SupportedFunctions
supported
functions

DataAccess

Session
create
data
access
session
in
string
session
name

raises

DuplicateName


DataAccess

Session
create
data
access
session
for
view

in
string
session
name

in
string
view
name



raises

DuplicateName

InvalidView



AlarmsAndEvents

Session
create
alarms
and
events
session

in
string
session
name


raises

DuplicateName



AlarmsAndEvents

Session

create
alarms
and
events
session
for
view

in
string
session
name

in
string
view
name


raises

DuplicateName

InvalidView



Strings
find
views




Inspection
inspect




}
}


#endif




DAIS
SERVER
IDL

ServerState

An
enumeration
of
the
states
a
Server
may
have




EnumValue

Description



SERVER
STATE
RUNNING

The
server
is
running
normally

This
is
the
usual
state
for
a
server




SERVER
STATE
FAILED

A
vendor
specific
fatal
error
has
occurred
within
the
server

The
server
is
no
longer
functioning

The
recovery
procedure
from
this
situation
is
vendor
specific




SERVER
STATE
NOCONFIG

The
server
is
running
but
has
no
configuration
information
loaded
and
thus
cannot
function
normally

This
state
implies
that
the
server
needs
configuration
information
in
order
to
function

Servers
that
do
not
require
configuration
information
should
not
return
this
state




SERVER
STATE
SUSPENDED

The
server
has
been
temporarily
suspended
via
some
vendor
specific
method
and
is
not
getting
or
sending
data

Note
that
Quality
will
be
returned
as
OPC
QUALITY
OUT
OF
SERVICE




SERVER
STATE
TEST

The
server
is
in
Test
Mode

The
outputs
are
disconnected
from
the
real
hardware
but
the
server
will
otherwise
behave
normally

Inputs
may
be
real
or
may
be
simulated
depending
on
the
vendor
implementation

Quality
will
generally
be
returned
normally




ServerStatus



Member

Description



start
time

Time
the
server
was
started

This
is
constant
for
the
server
instance
and
is
not
reset
when
the
server
changes
states

Each
instance
of
a
server
should
keep
the
time
when
the
process
started




current
time

The
current
time
as
known
by
the
server




server
state

The
current
status
of
the
server

Refer
to
ServerState
enumeration




session
count

The
total
number
of
sessions
created
by
clients
for
this
server




major
version

The
major
version
of
the
server
software






minor
version

The
minor
version
of
the
server
software




build
number

The
‘build
number’
of
the
server
software




vendor
info

Vendor
specific
string
providing
additional
information
about
the
server

It
is
recommended
that
this
mention
the
name
of
the
company
and
the
type
of
device
s

supported




supported
functions

A
constant
that
tells
what
functions
are
implemented
by
the
DAIS
server

e
g


Data
Access

Alarms
&
Events
or
both



Inspection

An
optional
interface
intended
to
be
specialized
into
a
vendor
specific
inspection
object

The
inspection
object
is
intended
to
expose
server
internal
details
for
debugging
and
inspection
purposes


Server

An
object
implementing
the
DAIS
server

A
DAIS
server
might
provide
more
than
one
view
on
nodes

A
view
is
a
specific
hierarchical
organization
of
nodes
and
nodes
may
appear
in
more
than
one
hierarchical
structure

for
example

a
functional
structure
or
a

location
structure
as
defined
by
IEC
1346-1


refer
also
to
Section
2
4

“IEC
1346-1


Structuring
and
Naming
?
on
page
2-7



DuplicateName

An
exception
raised
when
an
object
is
created
and
the
name
already
exists

No
object
is
created
if
the
exception
is
raised

Is
used
for
session
and
group
manager
objects


InvalidView

An
exception
raised
when
an
invalid
view
is
specified

An
invalid
view
is
if
the
view
name
does
not
exist
or
a
view
not
intended
for
the
type
of
session
is
used

for
example

a
view
for
data
access
is
used
for
alarms
&
events



statusAn
attribute
holding
the
ServerStatus
create
data
access
session


A
method
for
creation
of
a
data
access
session
object

The
default
view
will
be
used




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
data
access
session
for
view



A
method
for
creation
of
a
data
access
session
object
using
a
view
of
nodes




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




view
name

The
name
of
the
view
to
open

If
no
name
is
supplied

the
default
view
will
be
used




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
alarms
and
events
session



A
method
for
creation
of
an
alarms
&
events
session
object

The
default
view
will
be
used




Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




create
alarms
and
events
session
for
view



A
method
for
creation
of
an
alarms
&
events
session
object
using
a
view
of
areas

This
allows
a
server
to
support
different
area
structures
for
different
purposes

for
example

operational
responsibility

workorder
management





Parameter

Description



name

The
name
of
the
session

If
an
empty
name
is
supplied

the
server
will
create
a
name
for
the
session

If
a
duplicate
name
is
supplied

no
session
is
generated




view
name

The
name
of
the
view
to
open




return

A
reference
to
the
created
DAIS

DataAccess

Session
object




find
views



A
method
to
get
the
names
for
the
server
supported
views




Parameter
Description
return
A
sequence
of
view
names


inspect



A
method
for
creation
of
an
inspection
object




Parameter
Description
return
The
inspection
object


Session
Management





Client

Client


DAIS

Server
DAIS

ServerDataAccess


DAIS

DataAccess

Session
DataAccess


DAIS

DataAccess

SessionA&E

A&EDAIS

AlarmsAndEvents

SessionD

AIS

AlarmsAndEvents

SessionCreate
a
data
access
session
for
a
specific
structure
and
do
work

e
g

create
groups
and
subscribe
find
views



create
alarms
and
events
session



Do
work
with
alarms
&
events
session
e
g

create
an
AESubscription
create
data
access
session
for
view



Get
the
available
views
destroy



destroy




Figure
3-8
Session
management
interaction




Contents

This
chapter
contains
the
following
sections




Section
Title

Page




“Information
Model?



4-1





“API?



4-8




The
data
access
interface
provides
a
client
with
a
way
to
read

write

or
subscribe
for
data

items

held
by
the
server

It
has
a
discovery
interface
where
a
client
can
browse
and
select
available
data

Selected
data
is
used
to
compose
groups
and
groups
are
used
in
read

write

or
subscribe
operations

To
get
subscribed
data

a
client
has
to
connect
a
callback
object
to
the
server
so
that
the
server
can
notify
the
clients
with
changed
data






Equipment
in
any
industrial
process
is
usually
modeled
as
entities
or
classes
in
computerized
systems

The
class
name
usually
reflects
the
type
of
equipment

Objects
from
such
classes
are
called
Real
World
Objects

RWOs

in
this
document

RWO
classes
have
properties
describing
equipment
characteristics

for
example

size

length

geometries

material

nameplate
data

as
well
as
application
specific
data

for
example

impedance
parameters

state
estimated
values


Depending
on
the
purpose
of
a
system
and
the
managed

industrial

process
the
RWOs
are
of
different
types
and
contain
different
properties

Some
RWOs
are
common
between
systems
and
independent
of
industrial
process
like
process
variables

that
is

measurement

state

and
control
variables

Other
RWOs
like
transmission
lines
and
breakers
are
specific
to
power
transmission


RWO
will
typically
have
properties
depending
on
the
RWO
type

for
example

measurement

transformer

and
what
application
or
usage
the
RWO
is
involved
in

Properties
are
defined
per
type
of
RWO







In
DAIS
RWOs
are
represented
by
Nodes

Property
instances
at
a
node
are
represented
by
Items

An
item
may
represent
a
measurement
value

a
control
output
value

or
any
parameter

for
example

a
limit
value

a
unit

a
name

a
description


A
Type
and
properties
belonging
to
a
type
represent
an
RWO
type
by
DAISProperties

Nodes
are
hierarchically
structured
and
the
leafs
are
Items

This
is
shown

in
Figure
4-1





Instance
data

nodes
and
items
Meta
data

data
about
nodes
and
items
Item
cache
value


S
impleV
alue
cache
value
last
updated


DateTime
cache
value
quality


DAIS

Quality
scan
rate


uns
igned
long
access

rights


DAIS

Acc
essRights

from
DAISItem

Property
id


PropertyID
label


string
description


string
canonical
data
type


S
impleValueType

from
DAISProperty

0

n01


n+property
1Type
id


ResourceID
schema


ResourceID
label


string
description


string

f
rom
DAI
STy
pe

0

n0
1

n

n1

n0

n0
+aggregated
types

nNode
id


Resourc
eID
label


s
tring
type


ResourceID

from
DAISNode

1
0

n
+type
10

nNodeItemComponent
pathname


string

from
DAISNode

1
0

*
+parent
10

*
Figure
4-1
DAIS
data
access
server
information
model

The
Component
class
inherited
by
the
Node
and
Item
classes
models
the
hierarchical
structure

The
Node
may
contain
any
number
of
Components
as
described
by
the
Contains
role
having
the
cardinality
many

role
is
a
UML
concept

refer
to
[9]
for
an
explanation


A
Component
is
a
member
of
one
Node
as
described
by
the
MemberOf
role
having
the
cardinality
of
1

A
Component
can
be
both
a
Node
and
an
Item
through
the
inheritance

which
means
a
Node
can
contain
other
Nodes
or
Items

An
Item
cannot
contain
any
Components
as
it
only
inherits
the
MemberOf
role
and
not
the
Contains
role










Node
and
item
names
follow
OPC
[4]
and
IEC
1346-1
[10]

Each
Node
has
a
label
unique
among
other
Nodes
having
the
same
parent

that
is

are
MemberOf
the
same
Node

An
Item
does
not
have
an
own
label
but
uses
the
label
from
the
Property

Each
Item
in
a
Node
is
associated
with
different
DAISProperties
so
that
the
label
is
unique
among
other
items
at
the
same
node

The
labels
in
the
path
from
an
item
or
node
to
the

root
form
a
pathname

Labels
and
pathnames
are
explained
in
Figure
4-2





Root



label
=
Ceylon
pathname
=
Ceylon
type
=
Station



label
=
Cobden
pathname
=
Cobden
type
=
Station
label
=
Q1
pathname
=
Cobden
Q1
type
=
Breaker
label
=
G1
pathname
=
Cobden
G1
type
=
Generator
label
=
P
pathname
=
Cobden
G1
P
type
=
Measurement

A
Node



An
Item



label
=
ActivePower
pathname
=
Cobden
G1
P
ActivePower
value
=
50
time
stamp
=
2000-11-17
14
28
05
quality
=
Good
label
=
Unit
pathname
=
Cobden
G1
P
Unit
value
=
MW
time
stamp
=
2000-11-17
14
28
05
quality
=
Good
label
=
HighLimit
pathname
=
Cobden
G1
P

HighLimit
value
=
MW
time
stamp
=
2000-11-17
14
28
05
quality
=
Good

Figure
4-2
Labels
and
pathnames

A
delimiter

the
label
delimiter

might
separate
the
labels
in
a
pathname

Assuming
the
label
delimiter
is
a
“
?
An
example
of
an
item
pathname
for
a
measurement
value
in

Figure
4-2
is


Cobden
G1
P
Value
where
the
labels
are




•	
station

Cobden



•	
generator

G1



•	
active
power
measurement


P



•	
the
actual
measurement
value
property

Value



Exactly
how
the
pathname
is
composed
from
the
labels
is
server
specific
and
outside
the
scope
of
this
specification










Items
are
associated
with
values

Typically
an
item
value
provided
by
a
DAIS
server
is
read
from
a
device
and
transferred
to
one
or
more
clients

In
a
distributed
control
system

involving
remote
devices

as
indicated
in
Figure
4-3

communication
failures
might

make
item
values
not
available

To
cope
with
communication
failures
item
values
are
associated
with
a
quality

The
quality
indicates
the
reliability
of
the
item
value

Devices
usually
scan
item
values
at
a
certain
rate
and
item
values
will
be
transferred
to
the
DAIS
server
at
this
rate
or
some
other

In
the
server

item
values
will
appear
as
time
stamped
and
quality
coded
samples

A
server
that
keeps
item
values
in
a
local
cache
is
expected
to
always
hold
the
latest
sample

Other
item
related
informations
are
access-rights
and

scan-rate

This
information
is
shown
in
Figure
4-4

The
cache
value
is
the
latest
sample

received
from
a
device

the
cache
value
last
updated
the
time
when
the
cache
value
was
last
updated
or
validated

and
cache
value
quality
when
the
value
was
last
updated
or
validated


For
items

a
DAIS
server
exposes
the
following
information
to
clients




•	
the
value
and
its
data
type




•	
the
quality
of
the
value




•	
the
time
stamp
for
the
value




•	
the
fastest
scan
rate
with
which
the
value
can
be
expected
to
be
updated

and




•	
the
access
rights



To
make
access
of
item
values
efficient
and
avoid
reading
the
values
from
devices
each
time
a
client
requests
item
values

a
DAIS
server
is
expected
to
have
a
local
cache

The
mechanism
for
keeping
the
cache
up
to
date
is
server
specific
but
a
client
shall
expect
the
following
from
the
server




•	
Values
delivered
from
the
cache
reflect
the
latest
value
considering
update
rate
and
update
dead
bands

Based
on
the
agreed
update
rate

between
a
client
and
a
server

a
client
can
expect
that
the
server
will
validate
the
values
with
devices
with
the
agreed
update
rate




•	
The
dead
band
is
expected
to
be
checked
at
each
update
or
validation

Values
that
don’t
transgress
the
deadband
will
not
be
reported




•	
Time
stamps
delivered
from
the
cache
shall
reflect
when
the
values
were
updated
or
validated
with
the
devices
according
to
the
agreed
update
rate

The
time
stamp
gives
the
time
for
the
latest
successful
update
or
validation




•	
The
quality
shall
reflect
how
successful
the
server
has
been
in
keeping
the
values
updated
or
validated












DAIS
is
flexible
in
terms
of
what
types
and
properties
may
exist
in
a
server


In
OPC
there
is
a
recommendation
of
what
properties
are
expected
to
be
supported
by
a
data
access
server

These
recommended
properties
are
shown
in

Table
4-1

The
column

names
correspond
to
the
attributes
in
the
Property
class
seen
in
Figure
4-4



Table
4-1
Recommended
Properties



label

id

canonical
data

type

description



engineeringUnit

100

STRING
TYPE

Engineering
unit




description

101

STRING
TYPE

Description




maxValue

102

DOUBLE
TYPE

Maximum
value




minValue

103

DOUBLE
TYPE

Minimum
value




sensorMaximum

104

DOUBLE
TYPE

Maximum
value
from
an
analog
input
sensor




sensorMinimum

105

DOUBLE
TYPE

Minimum
value
from
an
analog
input
sensor




closedLabel

106

STRING
TYPE

Text
for
the
closed
state
for
a
discrete
status
input




openLabel

107

STRING
TYPE

Text
for
the
open
state
for
a
discrete
status
input




itemTimeZone

108

UNSIGNED
TYPE





109-4999


Reserved
by
OPC




For
a
system
having
data
described
by
a
particular
schema

for
example

the
CIM
for
power
systems

the
implementation
of
that
schema
as
seen
through
DAIS
has
to
be
decided

Either
a
mapping
to
the
recommended
OPC
properties
can
be
made
or
the
schema
can
be
exposed
as
is
through
DAIS

This
is
however
outside
the
scope
of
this
specification










The
classes
and
properties
defined
in
the
IEC
61970-30x

the
CIM

can
be
mapped
onto
the
OPC
recommended
properties

As
the
CIM
is
highly
structured

this
will
create
a
complicated
mapping

An
alternative
is
to
expose
CIM
as
is
through
the
DAIS

This
means
that
the
CIM
classes
and
their
properties
will
appear
the
same
as
seen
through
the
DAIS
as
through
the
DAF
interfaces

As
the
DAIS
requires
a
hierarchical
structuring
of
nodes

the
CIM
equipment
hierarchy
is
selected
as
the
hierarchy
exposed
through
the
DAIS


Besides
the
equipment
hierarchy
the
CIM
also
has
a
number
of
other
associations

Such
associations
may
be
made
visible
through
the
DAIS
interface
as
properties
holding
ResourceIDs


The
CIM
has
several
associations
between
RWOs
and
ways
to
structure
RWOs

The
requirement
from
DAIS
on
the
equipment
hierarchy
is
that
it
is
strictly
hierarchical

else
DAIS
is
transparent
to
any
information
model


For
RWOs
in
the
equipment
hierarchy
its
properties
simply
appear
as
items
at
the
nodes
representing
the
RWOs

The
DAIS
supports
navigating
across
associations
as
ResourceIDs
can
be
conveyed
by
SimpleValues


Utility
SCADA
EMS
systems
have
a
number
of
different
applications
calculating
alternate
measurement
values

In
the
IEC61970
draft
standard
this
is
modeled
by
Measurements
containing
one
or
more
MeasurementValues

as

shown
in
Figure
4-3





Limit
value
Lim
itSet
0
*
0

*1Measurement
<<RWO>>
0
*
0
+LimitSets

*1MeasurementValueSource
name
MeasurementV
alue
value
<<RWO>>
1
*
1

*1+MeasurementValueSource
1
Figure
4-3
Utility
SCADA
Measurement
Modeling

The
Measurement
and
the
MeasurementValue
appear
as
Nodes
and
their
properties
as
Items

In
the
example
from

Section
4
1
2

“Naming
?
on
page
4-3

th
e
Measurement
again
is
represented
by
the
pathname


Cobden
G1
P

Moving
down
to
MeasurementValue
will
add
its
label
to
the
pathname
so
that
it
may
look
like


Cobden
G1
P
Telem

If
the
MeasurementValue
property
for
the
value
has
the
label
Value

finally
the
pathname
for
the
item
will
be


Cobden
16kV
G1
P
Telem
Value
In
a
system
also
having
a
State
Estimated
MeasurementValue

the
pathname
for
state
estimated
value
might
be


Cobden
16kV
G1
P
SE
Value
Finally
if
the
state
estimated
value
is
to
replace
the
telemetered

this
can
be
implemented
picking
the
“best?
MeasurementValue
from
Measurement
itself
shortcutting
the
MeasurementValue
resulting
in
the
path

Cobden
G1
P
Value
The
CIM
classes
that
shall
be
navigable
and
whose
data
is
exposed
through
DAIS
are
listed
in

Table
4-2



Table
4-2
CIM
Classes



CIM
class

Properties
and
references



Measurement

All



MeasurementValue

All

MeasurementValues
are
expected
to
appear
in
the
hierarchical
structure
so
that
all
MeasurementValue
instances
are
visible
in
the
browser




MeasurementUnit

All



LimitSet

All

The
Measurement
to
LimitSet
reference
has
a
cardinality
1

*

It
is
expected
that
one
LimitSet
is
the
current
used
and
exposed
through
DAIS




Limit

As
the
LimitSet
to
Limit
reference
has
the
cardinality
1

*
the
mapping
through
DAIS
is
expected
to
be
a
number
of
properties
where
each
property
corresponds
to
one
limit
value




ValueAliasSet

As
the
ValueAliasSet
to
ValueToAlias
reference
has
cardinality
1

*
the
mapping
through
DAIS
is
expected
to
be
a
number
of
properties
where
each
property
corresponds
to
one
translation
from
numeric
to
symbolic
value




Classes
in
the
hierarchical
structure
above
Measurement


An
implementation
is
free
to
expose
any
hierarchical
structure
of
classes
above
the
Measurement

Multiple
and
different
structures
are
allowed
using
different
views

for
views
refer
to
Section
3
2
2

“DAIS
Server
IDL
?
on
page
3-30


An
implementation
is
also
free
to
expose
any
properties
from
these
classes





The
table
is
based
on
the
CIM
version
given
by
[11]

















The
IDL
is
divided
into
files

Each
file
is
modeled
as
a
package
in
UML

A
file
that

depends
on
declarations
made
in
another
file
needs
to
include
it

Figure
4-4
shows
how

the
IDL
files
depend
on
each
other




DAISCommon

from
Common

DAISDAIO
DAISGroupEntry

DAISItem
DAISNode

from
Common

DAISProperty
DAISType

from
Common


from
Common


DAISGroup
DAISDASimpleIO



DAISDASession
DAISDANode
DAISSession

from
Common

DAISServer


from
Server


Figure
4-4
Dependencies
between
data
access
IDL
files















The
DAIS

DataAccess

Session
object
implements
the
data
access
service
on
a
per
client
basis

A
data
access
session
object
has
a
number
of
services
provided
by
one
singleton
home
object
each

Each
home
object
provides
methods
for
manipulation
of
the
data
of
the
specific
type
they
provide

Rather
than
exposing
data
as
objects
with
interfaces
it
is
exposed
as
structs
or
sequences
of
structs

The
reason
is
that
a
large
number
of
data
items
will
become
a
performance
bottleneck
if
instantiated
as
objects
over
an
interface

The
DAIS

Group

IHome
object
is
the
only
object
to
expose
its
data
as
objects

that
is

the
DAIS

Group

Manager

Each
DAIS

Group

Manager
is
expected
to
connect
to
one
callback
object
implemented
by
the
client


Each
client
may
instantiate
one
or
more
Sessions

The
Session
objects
have
one
Type
and
Property
Home
object
each

The
client
shall
expect
that
all
Type
and
Property
Home
objects
expose
the
same
types
and
properties


The
session
object
corresponds
to
an
OPCServer
object


1
0

1
10

1



DAIS

Session

from
DAISSess
ion

<<Interface>>
status




DAIS

SessionStatus
callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy


DAIS

DataAccess

Session
<<Interface>>
group
home




DAIS

DataAccess

Group

IHome
simple
io
home


DAIS

DataAccess

SimpleIO

IHome


node
home




DAIS

DataAccess

Node

IHome
item
home




DAIS

DataAccess

Item

IHome
type
home




DAIS

Type

IHome
property
home




DAIS

Property

IHome



DAIS

ShutdownCallback

from
DAISSessi
on

<<Interface>>



0

10

1



11



Client

fro
m
DAISServer




11



0

*0

*



11



DAIS

Type

IHome

f
rom
DAIST
ype

<<Interface>>



DAIS

DataAccess

IO

Callback

from
DAISDAIO

<<Interface>>






DAIS

Property

IHome

from
DAISProperty

<<Interface>>



0

10

1



11



11



11



DAIS

DataAccess

Node

IHome

from
DAISDANode


<<Interface>>



DAIS

DataAccess

IO

ConnectionPoint

from
DAISDAIO

<<Interface>>



11



DAIS

DataAccess

Group

IHome

from
DAISGroup

<<Interface>>
DAIS

DataAccess

Item

IHome

from
DAI
SItem

<<Interface>>






11

1
0



n

10




DAIS

DataAccess

Group

Manager

from
DAISGroup

<<Interface>>



11



DAIS

DataAccess

SimpleIO

IHome

from
DAISDASi
mp
leIO

<<Interface>>




Figure
4-5
DAIS
data
access
session
IDL
in
UML











File

DAISDASession
idl
#ifndef

DAIS
DA
SESSION
IDL
#define

DAIS
DA
SESSION
IDL
#pragma
prefix
"omg
org"






Common
Information
#include
<DAISNode
idl>
#include
<DAISProperty
idl>
#include
<DAISSession
idl>






Data
Access
interface
#include
<DAISType
idl>
#include
<DAISItem
idl>
#include
<DAISDANode
idl>
#include
<DAISGroup
idl>
#include
<DAISDASimpleIO
idl>



module
DAIS
{
module
DataAccess
{



interface
Session


DAIS

Session
{



readonly
attribute
Group

IHome

group
home




readonly
attribute
SimpleIO

IHome

simple
io
home




readonly
attribute
Node

IHome

node
home




readonly
attribute
Item

IHome

item
home




readonly
attribute
Type

IHome

type
home




readonly
attribute
Property

IHome
}
}
}

#endif




DAIS
DA
SESSION
IDL

property
home




Session

Session
is
an
object
implementing
the
data
access
functions

It
inherits
common
functionality
as
shut
down
callbacks
and
session
status
from
DAIS

Session


group
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Group

IHome
object


node
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Node

IHome
object


item
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Item

IHome
object


type
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Type

IHome
object


property
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Property

IHome
object


















The
DAIS

DataAccess

Node
inherits
most
of
the
functionality
from
DAIS

Node

The
only
difference
is
that
it
supports
to
get
the
tree
root
node




0

*0

*



11
+parent


1
01

n0

n



Node
id


ResourceID
label


string
type


Resourc
eID

from
DAISNode

NodeItemComponent
pathname


string

from
DAISNode




11



0

n0

n



DAIS

DataAccess

Node

IHome
get
root


<<Interface>>
DAIS

Node

Iterator
max
left


next
n


reset


clone


destroy



from
DAISNode

<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids



from
DAISNode

<<Interface>>

Figure
4-6
DAIS
data
access
node
IDL
in
UML











File

DAISDANode
idl#ifndef

DAIS
DANODE
IDL#define

DAIS
DANODE
IDL#pragma
prefix
"omg
org"#include
<DAISNode
idl>
module
DAIS
{module
DataAccess
{module
Node
{
interface
IHome


DAIS

Node

IHome{
ResourceID
get
root




}


}
}
}


#endif




DAIS
DANODE
IDL

IHome

An
object
used
for
browsing
nodes

Most
functionality
is
inherited
from
the
DAIS

Node

IHome
interface


get
root



Get
the
root
node
of
the
whole
tree
of
nodes




Parameter
Description
return
The
root
node
identification


Hierarchical
browsing





Client
Client


DAIS

DataAccess

Node

IHome
DAIS

DataAccess

Node

IHome


DAIS

Node

Iterator
DAIS

Node

Iterator

DAIS

DataAccess

Session
DAIS

DataAccess

Sessionnode
home



get
root



find
by
parent



next
n



find
by
parent



Get
some
nodes
at
the
root
Pick
one
of
the
nodes
at
the
root
and
get
it's
children
next
n



Get
some
nodes
among
the
children
to
the
node
picked
at
the
root
Figure
4-7
Hierarchical
browsing
interaction

Browsing
by
type





Client

Client


DAIS

DataAccess

Session
DAIS

DataAccess

SessioAcess

Node

IHomeAn


DAIS

Datac
DAIS

Dataccess

Node

IHome


DAIS

Node

Iterator

DAIS

Node

Iteratornode
home



find
by
type



next
n



Find
all
nodes
of
a
certain
type
in
sub-tree

in
this
case
the
root
get
root



next
n




Figure
4-8
Browsing
by
type
interaction
















An
item
is
a
property
of
a
node

While
a
node
generally
represents
a
real-world
object

an
item
represents
some
characteristic
of
that
object

for
example

measurement
value

control
variable

or
parameter
related
to
the
measurement
control
process


The
concept
of
an
item
in
DAIS
corresponds
to
the
item
in
OPC

More
precisely

it
corresponds
to
the
“leafs?
in
the
OPC
IOPCBrowseServerAddressSpace
interface

In
the
Resource
Description
Framework

RDF

data
model

the
item
corresponds
to
a
combination
of
a
subject
and
a
predicate

that
is

a
resource
and
a
property


A
node
may
have
many
items

each
representing
a
different
characteristic
of
the
same
real
world
object

An
item
might
represent
a
measured
variable

a
calculated
variable

a
control
variable

or
a
configuration
parameter

An
item
will
typically
have
many
values
where
each
value
corresponds
to
a
time
stamped
sample

a
single
item
value
corresponds
to
a
single
statement
in
the
RDF
model


Each
sample
will
also
have
its
own
quality

An
item
value
is
then
qualified
by
a
time
stamp
and
a
quality


An
item
value
and
its
qualifications
are
represented
by
six
fixed
attributes




•	
value
-
the
value




•	
time
stamp
-
the
time
when
the
value
was
last
updated




•	
quality
-
the
quality
of
the
value




•	
canonical
data
type
-
the
data
type
of
the
value

This
actually
belongs
to
the
property

see
Property

but
it
is
mirrored
at
the
item




•	
access
rights
-
tells
if
the
value
is
read
only

write
only

or
both
read
write

The
access
right
is
common
for
all
item
values
and
belongs
to
the
item




•	
scan
rate
-
the
fastest
rate
with
which
the
value
can
be
expected
to
be
updated

The
scan
rate
is
common
for
all
item
values
and
belongs
to
the
item





For
an
information
model
describing
this
refer
to
Section
4
1
1

“Nodes

Items

Types


and
Properties
?
on
page
4-2
and
Section
4
1
3

“Item
Values
?
on
page
4-4



Each
item
has
a
universal
identity
given
by
its
ItemID

The
ItemID
is
made
up
of
the
ResourceID
of
a
node
and
the
PropertyID
of
a
property

The
ItemID
of
an
item
is
the
same
in
all
views
provided
by
a
DAIS
server

Clients
may
construct
ItemIDs
given
the
identities
of
nodes
and
properties


DAIS
servers
may
be
coordinated
with
DAF
servers
so
that
valid
ItemIDs
can
be
constructed
from
DAF
ResoureIDs


Within
each
view
provided
by
the
server

an
item
has
a
label
that
is
unique
among
all
items
belonging
to
the
same
node

Within
each
view

an
item
has
a
unique
pathname


The
pathname
is
a
string
that
contains
the
item’s
label
and
the
pathname
of
its
node


The
pathname
must
be
a
valid
URI

but
apart
from
that
the
syntax
of
pathnames
is
implementation
dependent


Note
–
In
OPC
the
pathname
is
the
primary
way
to
identify
items
and
is
called
the
ItemID

In
DAIS
the
ResourceID

PropertyID
pair
is
the
primary
identification
and
so
it
is
called
the
ItemID

This
is
a
potential
point
of
confusion

The
two
ItemIDs
play
approximately
the
same
role
in
OPC
and
DAIS
respectively

but
they
are
not
the
same
type


The
item
interfaces
permit
the
stock
of
items
to
be
browsed

Once
an
item
is
located

the
group
interfaces
are
used
to
deliver
its
values

selected
by
source

at
successive
times

In
addition

the
item
interfaces
provide
the
most
current
value
for
the
default
source

In
either
case
the
item
value
and
qualifications
are
represented
by
the
six
fundamental
attributes
listed
above


The
Item
IDL
defines
a
main
interface
Home
for
browsing
among
hierarchically
structured
items

leaf
nodes


The
information
model
describing
the
hierarchical
structure
is
found

in
Section
4
1
1

“Nodes

Items

Types

and
Properties
?
on
page
4-2





DAIS

DataAccess

Item

IHome
<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnam
es


get
ids


get
access
paths


11


11


0

0
n
n



0

0
n
n



Item
cache
value


SimpleV
alue
cache
value
last
updated


DateTim
e
cache
value
quality


DAIS

Quality
scan
rate


unsigned
long
access
rights


DAIS

AccessRights
NodeItem
Component

fro
m
DA
IS
Nod
e

pathname


string



DAIS

DataAccess

Item

Iterator
<<Interface>>
max
left


next
n


reset


clone


destroy



Figure
4-9
DAIS
data
access
item
IDL
in
UML











File

DAISItem
idl
#ifndef

DAIS
ITEM
IDL
#define

DAIS
ITEM
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
DataAccess
{
module
Item
{

struct
Description

{

ItemID
id


string
label


SimpleValue
value



includes
the
canonical
data
type

Quality
dais
quality


DateTime
time
stamp


AccessRights
access
rights


unsigned
long
scan
rate

}

typedef
sequence<
Description
>Descriptions


interface
Iterator
{

boolean
next
n






in

unsigned
long

n





out

Descriptions

items












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownResourceID
{string
reason
}

exception
UnknownItemID
{string
reason
}

exception
InvalidFilter
{string
reason
}

exception
InvalidValueType
{string
reason
}

exception
UnkownTypeID
{string
reason
}

exception
InvalidAccessRight
{string
reason
}


Description
find


in
ItemID
item


raises

UnknownItemID



Descriptions
find
each

in
ItemIDs
items


raises

UnknownItemID



Iterator
find
by
parent


in
ResourceID
node

in
string
filter
criteria

in
SimpleValueType
data
type
filter

in
AccessRights
access
rights
filter



raises

UnknownResourceID




InvalidFilter




InvalidValueType




InvalidAccessRight





Iterator
find
by
type





in
ResourceID

node




in
ResourceIDs

type
filter




in
string

filter
criteria




in
SimpleValueType

data
type
filter




in
AccessRights

access
rights
filter





raises

UnknownResourceID





InvalidFilter





InvalidValueType





UnkownTypeID





InvalidAccessRight






Strings
get
pathnames






in
ItemIDs

items










ItemIDs
get
ids






in
Strings

pathnames










Strings
get
access
paths






in
ItemID

item





raises

UnknownItemID






}
}
}
}





#endif




DAIS
ITEM
IDL




Description




A
struct
describing
an
item







Member

Description



id

The
identification
of
this
item




label

The
label

single
level
designation

of
the
item




value

The
current
value
sample
for
the
item

The
SimpleValue
also
contains
the
data
type




dais
quality

The
current
quality
of
the
value




time
stamp

The
time
stamp
for
the
value
sample




access
rights

States
if
the
value
is
read

write

or
both
read
and
write




scan
rate

States
the
highest
update
rate
that
can
be
expected




Iterator

Refer
to

Section
4
1
5

“Utility
SCADA
EMS
Measurement
Model
?
on
page
4-5

This

interface
corresponds
to
the
OPC
interface
EnumString
with
the
difference
that
the
Iterator
return
the
Description
struct
instead
of
a
single
string


IHome

An
object
used
for
browsing
items
and
corresponds
to
the
IOPCBrowseServerAddressSpace


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


UnknownItemID

An
exception
stating
that
the
resource
or
property
in
the
ItemID
is
unknown


For
methods
taking
a
sequence
of
item
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


InvalidFilter

An
exception
stating
the
filter
criteria
string
is
not
correct

The
likely
reason
behind
this
exception
is
an
erroneously
entered
string


InvalidValueType

An
exception
stating
that
the
SimpleValueType
does
not
exist


UnknownTypeID

An
exception
stating
one
or
more
TypeIDs
does
not
exist


InvalidAccessRight

An
exception
stating
that
the
access
rights
do
not
exist


find



For
a
given
item
browse
position

return
information
about
that
item




Parameter

Description



item

An
item
identification




return

The
item
description




find
each




For
a
sequence
of
items

return
information
about
each
item




Parameter

Description



items

A
sequence
of
item
identifications




return

An
iterator
holding
the
item
descriptions




find
by
parent




For
a
given
node
identification

return
child
items
to
that
node

Hence
to
reach
all
items
using
this
method
repeated
calls
must
be
made
for
each
node
level

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
LEAF




Parameter

Description



node

The
parent
node
identification




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
only
items
with
pathnames
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





data
type
filter

Select
items
having
the
specified
canonical
data
type




access
rights
filter

Select
items
having
the
specified
access
rights




return

An
iterator
holding
item
descriptions
for
items
•
that
are
child
to
the
parent
node

•
matching
the
filter
criteria

data
type
filter

and
access
rights
filter




find
by
type



For
a
sub-tree
given
by
the
node
parameter

return
all
child
items
matching
the
filter
criteria

This
will
return
all
items
under
the
given
sub-tree
root
node

This
will
make
the
items
in
the
sub-tree
to
appear
flattened
out

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
FLAT




Parameter

Description



node

The
identification
for
the
node
defining
the
sub-tree




type
filter

Select
nodes
in
the
sub-tree
having
a
type
matching
any
of
the
types
listed
in
the
type
filter






filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
only
items
with
pathnames
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





data
type
filter

Select
items
having
the
specified
canonical
data
type




access
rights
filter

Select
items
having
the
specified
access
rights




return

An
iterator
holding
item
descriptions
for
items
•
that
are
child
to
nodes
in
the
sub-tree
and
nodes
having
a
type
matching
the
type
filter

•
matching
the
filter
criteria

data
type
filter

and
access
rights
filter




get
pathnames



Translate
a
sequence
of
item
identifications
to
the
corresponding
sequence
of
pathnames

If
an
item
fails
to
translate
to
a
pathname

due
to
an
unknown
identification


the
corresponding
pathname
is
an
empty
string




Parameter

Description



items

The
sequence
of
items




return

The
corresponding
sequence
of
pathnames




get
ids



Translate
a
sequence
of
pathnames
to
the
corresponding
sequence
of
item
identifications

If
a
pathname
fails
to
translate
to
an
item
identification

due
to
an
unrecognized
pathname

the
corresponding
item
identification
is
NULL


get
access
paths



Get
the
possible
communication
paths
how
data
can
be
retrieved
for
the
node

An
access
path
is
expected
to
be
human
readable
so
that
a
human
can
pick
one
and
feed
it
back
to
the
server
as
the
preferred
path

via
other
interfaces





Parameter

Description



item

An
item
identification




return

A
sequence
of
possible
access
paths
for
the
item




Browsing
Items





Client

Client


DAIS

DataAccess

Item

IHome

DAIS

DataAccess

Item

IHome


DAIS

DataAccess

Item

Iterator

DAIS

DataAccess

Item

Iterator

DAIS

DataAccess

Session

DAIS

DataAccess

Sessionnode
home



find
by
parent



next
n



item
home



find
by
parent



Get
the
items
for
a
particular
node
Get
some
item
descriptions
for
the
particular
node
Get
the
items
for
another
node
Get
some
node
of
interest

refer
to
browsing
of
Nodes

Figure
4-10
Browsing
items
interaction
Navigate
across
associations

find
by
parent








Client
Client


DAIS

DataAccess

Item

IHome

DAIS

DataAccess

Item

IHomeataccess

Node

IHomea

DAIS

DA

DAIS

DtaAccess

Node

IHomeGet
information
about
each
item
at
a
known
node
find



Pick
an
item
holding
a
ResourceID
and
get
the
node
information
for
that
ResourceID
find
by
parent



Get
the
item
information
for
the
new
node

Figure
4-11
Navigating
across
associations
interaction

















These
are
definitions
for
transmitting
item
values
to
clients

Interfaces
are
defined
for
server
side
read
and
write
operations
and
client
side
callback
operations

Clients
shall
implement
the
Callback
object
for
the
server
to
use
at
transfer
of
data

A
client
may
have
any
number
of
callback
objects

The
client
shall
connect
each
callback
object
to
a
server
object
implementing
ConnectionPoint


The
IO
interfaces
support
three
different
ways
to
read
data
and
two
different
ways
to
write
data




Read
data



•	
Synchronous
read
where
the
data
is
received
at
return
from
the
sync
read


method




•	
Asynchronous
read
where
the
data
is
returned
at
the
Callback
object




•	
Subscription
where
data
is
sent
spontaneously
by
the
server
at
the
callback
object








Write
data



•	
Synchronous
write
returning
to
the
client
once
all
the
written
data
has
reached
the
devices



•	
Asynchronous
write
returning
when
the
data
is
received
by
the
DAIS
server

A
callback
on
Callback
is
sent
by
the
server
once
the
written
data
has
reached
the
devices




Each
item
value
is
transmitted
in
a
struct
with
a
timestamp
and
quality
indication

A
sequence
of
this
struct
is
either
sent
via
the
callback
object
or
directly
in
read
or
write
calls


In
OPC
the
IO
interface
corresponds
to
the
OPC
interfaces
IOPCSyncIO

IOPCAsyncIO

and
IOPCDataCallback




DAIS

DataAccess

IO

SyncIO
<<Interface>>
sync
read


sync
write


DAIS

DataAccess

IO

ConnectionPoint
<<Interface>>
callback




DAIS

DataAccess

IO

Callback
callback
callback


DAIS

DataAccess

IO

Callback




11


0

0
1
1



DAIS

DataAccess

IO

Callback
<<Interface>>
on
data
change


on
read
complete


on
write
complete


on
cancel
complete


0

*0

*


11



Client

from
DAIS
Server




DAIS

DataAccess

IO

AsyncIO
<<Interface>>
async
read


async
write


refresh


cancel


set
enable


get
enable


DAIS

DataAccess

IO

ItemState
<<struct>>
client
handle


ClientItemHandle
time
stamp


DateTime
dais
quality


DAIS

Quality
value


SimpleValue

Figure
4-12
DAIS
data
access
IO
IDL
in
UML

The
DAISConnectionPoint
callback


methods
correspond
to
a
get
or
set
method
for
the
callback
attribute














File

DAISDAIO
idl#ifndef

DAIS
DAIO
IDL#define

DAIS
DAIO
IDL#pragma
prefix
"omg
org"#include
<DAISCommon
idl>
module
DAIS
{

module
DataAccess
{module
IO
{
enum
DataSource
{


DS
CACHE



DS
DEVICE

}


struct
ItemState

{
SimpleValue
value

DateTime
time
stamp

Quality
dais
quality

ClientItemHandle
client
handle


}
typedef
sequence<ItemState>
ItemStates

struct
ItemUpdate
{
ServerItemHandle
server
handle

SimpleValue
value


}
typedef
sequence<ItemUpdate>
ItemUpdates

interface
SyncIO{
ItemStates
sync
read


in
DataSource
data
source

in
ServerItemHandles
server
handles

out
ItemErrors
errors





ItemErrors
sync
write





in

ItemUpdates
updates










}





typede
f
unsi
gned
long

CancelID




int

erface
AsyncIO



{






exception
NotConnected{string
reason
}

exception
InvalidCancelID{string
reason
}

exception
NotActive{string
reason
}


CancelID
async
read


in
ServerItemHandles
server
handles

in
DataSource
data
source

in
unsigned
long
transaction
id



raises

NotConnected

NotActive



CancelID
async
write


in
ItemUpdates
updates


in
unsigned
long
transaction
id


raises

NotConnected



CancelID
refresh



in
DataSource
data
source



raises

NotConnected
NotActive



void
cancel


in
CancelID
cancel
id
in
unsigned
long
transaction
id



raises

InvalidCancelID



attribute
boolean
enabled

}


interface
Callback
{

void
on
data
change


in
unsigned
long
transaction
id

in
boolean
all
quality
good

in
ItemStates
states





void
on
read
complete


in
unsigned
long
transaction
id

in
boolean
all
quality
good

in
ItemStates
states

in
ItemErrors
errors





void
on
write
complete


in
unsigned
long
transaction
id

in
ItemErrors
errors





void
on
cancel
complete







in

unsigned
long

transaction
id













}








interface
ConnectionPoint
{

attribute
Callback
cllbck

}
}
}
}

#endif




DAIS
DAIO
IDL
DataSource



Member

Description



DS
CACHE

Data
cached
in
the
server
is
requested




DS
DEVICE

Data
from
the
device
is
requested

This
will
force
a
read
from
the
device
or
RTU

A
read
from
device
will
be
made
regardless
of
the
group
or
item
active
status
and
no
group
NotActive
exception
will
be
forced




ItemState

The
struct
is
the
major
carrier
of
data
conveyed
over
the
interface

It
is
the
“message?
holding
the
payload




Member

Description



value

The
value
itself




time
stamp

The
time
stamp
when
the
value
was
last
updated




quality

The
quality
for
the
value




client
handle

A
client
side
handle
enabling
the
client
to
make
a
quick
look
up
of
the
item
in
its
internal
data
structures




ItemUpdate

The
struct
carry
an
update
for
an
item




Member

Description



server
handle

A
server
side
handle
enabling
the
server
to
make
a
quick
look
up
of
the
item
in
its
internal
data
structures




value

The
value
that
shall
be
used
in
the
update




SyncIO

An
interface
for
the
synchronous
operations


sync
read



Synchronous
read
of
items

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




Parameter

Description



data
source

The
source
from
where
to
read
the
data




server
handles

A
sequence
specifying
the
whole
or
a
subset
of
the
server
side
handles
as
defined
via
the
DAIS

GroupEntry

Manager
interface




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
INVALID
DAIS
HANDLE



return

A
sequence
of
ItemStates
for
the
items




sync
write



Synchronous
write
of
item
values
to
devices

not
the
internal
server
cache


The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
all
or
a
subset
of
the
items
defined
for
a
GroupEntry

Manager

The
ItemUpdate

value
member
is
used
to
update
the
items
in
devices




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
INVALID
DAIS
HANDLE
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



AsyncIO

An
interface
for
asynchronous
read
or
write
operations


NotConnected

An
exception
telling
that
there
is
no
callback
object
connected
by
the
client


InvalidCancelID

An
exception
telling
that
the
supplied
cancel
id
number
is
not
recognized


NotActive

An
exception
telling
that
the
group
or
all
items
in
the
group
is
inactive

Only
issued
when
read
from
cache


async
read



Asynchronous
read
of
items
from
devices

OPC
may
report
read
errors
both
at
return
from
async
read


and
at
on
read
complete



DAIS
will
report
all
errors
at
on
read
complete







Parameter

Description



server
handles

A
sequence
specifying
the
whole
or
a
subset
of
the
server
side
handles

as
defined
via
the
DAIS

GroupEntry

Manager
interface




data
source

The
source
from
where
to
read
the
data

When
reading
from
cache

inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
read
operation




async
write



Asynchronous
write
of
item
values
to
devices

not
the
internal
server
cache


OPC
may
report
write
errors
both
at
return
from
async
write


and
at
on
write
complete



DAIS
will
report
all
errors
at
on
write
complete






Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
all
or
a
subset
of
the
items
defined
for
a
DAIS

GroupEntry

Manager

The
ItemUpdate

value
member
is
used
to
update
the
items
in
devices




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
write
operation




refresh



Initiate
a
complete
asynchronous
read
transfer
for
all
item
entries
defined
via
the

DAIS

DataAccess

GroupEntry

Manager
interface

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE


The
cyclic
on
data
change
reporting
continues
unaffected
by
a
refresh
call

However

items
still
unchanged
after
a
refresh
will
not
be
reported
in
a
succeeding
on
data
change
call




Parameter

Description



data
source

The
source
from
where
to
read
the
data




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
data
change
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
refresh
operation




cancel



Cancel
on
ongoing
refresh

async
read

or
async
write
operations

The
server
is
expected
to
acknowledge
a
successfully
initiated
cancel
operation
with
an
on
cancel
complete


callback




Parameter

Description



cancel
id

The
server
generated
cancellation
number
for
the
operation




to
cancel




enable

An
attribute
used
to
enable
or
disable
the
spontaneous
on
data
change


callbacks

The
enable
state
does
not
affect
on
data
change
response
to
refresh
calls

When
a
group
is
created
it
is
enabled
by
default


Callback

An
interface
implemented
by
the
client
and
used
by
the
server
to
send
data
to
the
client


on
data
change



The
method
is
called
by
the
server
when
spontaneous
changes
occur
or
when
the
client
has
requested
an
explicit
refresh

Only
active
items
are
reported
in
spontaneous
calls




Parameter

Description



transaction
id

If
the
call
is
in
response
to
a
refresh

the
transaction
number
for
that
refresh
call

If
the
call
is
autonomous
due
to
one
or
more
spontaneous
changes

the
number
is
zero




all
quality
good

All
item
quality
values
are
good




item
states

A
sequence
of
requested
or
spontaneously
changed
ItemStates




on
read
complete



The
method
is
used
by
the
server
to
report
data
in
response
to
an
asynchronous
read




Parameter

Description



transaction
id

The
transaction
number
for
the
corresponding
read




all
quality
good

All
item
quality
values
are
good

This
requires
that
no
errors
are
reported
in
the
error
parameter
below




item
states

A
sequence
of
ItemStates
matching
the
read
operation




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
initially
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
ERROR
INVALID
DAIS
HANDLE



on
write
complete



The
method
is
used
to
report
the
success
of
an
asynchronous
write
operation




Parameter

Description



transaction
id

The
transaction
number
for
the
corresponding
write




errors

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
all
write
operations
initially
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
INVALID
DAIS
HANDLE
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



on
cancel
complete



The
method
is
used
to
acknowledge
the
completion
of
a
successfully
initiated
cancel
call




Parameter
Description
transaction
id
The
transaction
number
for
the
corresponding
cancel


ConnectionPoint

An
interface
used
by
the
client
to
connect
or
disconnect
a
client
callback
object
at
the
server


callback

An
attribute
referencing
the
callback
object


In
an
implementation
one
get
and
one
set
method
will
implement
the
callback
attribute

Due
to
limitation
in
the
UML
tool
used
to
draw
the
diagrams

the
attribute
is
represented
by
the
two
methods
connect
and
disconnect
















A
group
has
a
collection
of
group
entries

Each
group
entry
associates
the
group
with
an
item

An
ItemID
identifies
a
group
entry
within
its
group

The
pathname
of
an
item
may
be
used
as
an
alternative
to
the
ItemID
when
the
group
entry
is
created

see

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15




In
OPC
the
GroupEntry
interface
corresponds
to
the
interface
IOPCItemMgt







DAIS

DataAccess

GroupEntry

Manager
<<Interface>>
create
entries


validate
entries


remove
entries


set
active
state


set
inactive
state


set
client
handles


set
data
types


create
group
entry
iterator





11



0

0
n
n


11


0

0
*
*



GroupEntry
pathname


string
item


DAIS

ItemID
active


boolean
access
path


string
client
handle


ClientItemHandle
requested
data
type


SimpleValueType
access
rights


AccessRights
canonical
data
type


SimpleValueType



DAIS

DataAccess

GroupEntry

Iterator
<<Interface>>
max
left


next
n


reset


clone


destroy



Figure
4-13
DAIS
data
access
group
entry
IDL
in
UML











File

DAISGroupEntry
idl
#ifndef

DAIS
GROUP
ENTRY
IDL
#define

DAIS
GROUP
ENTRY
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
DataAccess
{
module
GroupEntry
{

struct
Description



{



ServerItemIdentification

server
item
id




string

access
path




ClientItemHandle

client
handle




SimpleValueType

requested
data
type




boolean

active




}





typedef
sequence<Description
>

Descriptions




struct
DetailedDescription




{






ItemID

item





string

pathname





string

access
path





ServerItemHandle

server
handle




ClientItemHandle
client
handle
SimpleValueType
requested
data
type
SimpleValueType
canonical
data
type
AccessRights
access
rights
boolean
active

}
typedef
sequence<DetailedDescription>
DetailedDescriptions

struct
Result
{
ServerItemHandle
server
handle

ClientItemHandle
client
handle

AccessRights
access
rights

SimpleValueType
canonical
data
type


}
typedef
sequence<Result>
Results

struct
HandleAssociation
{
ServerItemHandle
server
handle

ClientItemHandle
client
handle


}

typedef
sequence<HandleAssociation>HandleAssociations


struct
DataTypeDescription

{
ServerItemHandle
server
handle

SimpleValueType
requested
data
type


}

typedef
sequence<DataTypeDescription>DataTypeDescriptions


interface
Iterator
{

boolean
next
n

in
unsigned
long
n
out
DetailedDescriptions
entries



void
reset



Iterator
clone



void
destroy




}


interface
Manager
{

Results
create
entries

in
Descriptions
entries
out
ItemErrors
errors




Results
validate
entries





in

Descriptions

entries




out

ItemErrors

errors










ItemErrors
remove
entries






in

ServerItemHandles

server
handles










ItemErrors
set
active
state






in

ServerItemHandles

server
handles










ItemErrors
set
inactive
state






in

ServerItemHandles

server
handles










ItemErrors
set
client
handles






in

HandleAssociations

handle
associations










ItemErrors
set
data
types






in

DataTypeDescriptions

descriptions










Iterator
create
group
entry
iterator



}
}
}
}
#endif




DAIS
GROUP
ENTRY
IDL

Description
The
struct
describes
a
group
entry
for
an
item

The
client
to
configure
new
entries
in
a
group
uses
it

It
directly
corresponds
to
the
OPCItemDef
struct




Member

Description



server
item
id

The
identification
of
the
item




access
path

The
access
path
used
by
the
server
to
connect
to
the
device
and
sensor

An
empty
string
as
input
tells
the
server
to
select
the
access
path




client
handle

The
client
provided
handle
to
the
item




requested
data
type

The
data
type
requested
by
the
client
for
the
value




active

Tells
if
the
item
is
active
and
data
from
devices
is
updated
in
the
cache




DetailedDescription

The
struct
is
used
to
deliver
group
entry
information
to
the
client

In
OPC
this
is
made
with
the
struct
OPCITEMATTRIBUTES

Description
is
used
for
both
these
OPC
structs




Member

Description



item

The
item
identification
by
an
ItemID




pathname

A
string
concatenating
the
labels
for
all
nodes
in
the
path
from
the
item
up
to
the
root




access
path

The
access
path
used
by
the
server
to
connect
to
the
device
and
sensor

An
empty
string
as
input
tells
the
server
to
select
the
access
path




server
handle

Server
provided
handle
for
the
item




client
handle

Client
provided
handle
for
the
item




requested
data
type

The
data
type
requested
by
the
client
for
the
value




canonical
data
type

The
data
type
the
server
uses
internally
for
the
value




access
rights

The
access
rights

read

write

and
read-write




active

Tells
if
the
item
is
active
and
data
from
devices
is
updated
in
the
cache




Result

The
struct
is
used
to
transfer
the
result
from
a
create
entries


or
validate
entries


call
back
to
a
client

In
OPC
the
corresponding
struct
is
OPCITEMRESULT




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




client
handle

The
supplied
client
handle
for
the
item




access
rights

The
access
rights

read

write

and
read-write




canonical
data
type

The
data
type
the
server
uses
internally
for
the
value




HandleAssociation

The
struct
is
used
to
change
the
association
between
server
handles
and
client
handles
in
the
set
client
handle


method




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




client
handle

The
new
client
handle
wanted
by
the
client




DataTypeDescription

The
struct
is
used
to
change
the
data
type
of
the
value
delivered
in
the
ItemState
struct




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




requested
data
type

The
new
data
type
wanted
by
the
client




Iterator

Refer
to

Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10

The
interface
directly

corresponds
to
the
EnumOPCItemAttributes
interface


Manager

An
interface
for
creation
and
browsing
of
group
entries

The
interface
directly
corresponds
to
the
IOPCItemMgt
interface


create
entries



Adds
one
or
more
entries
to
a
group




Parameter

Description



entries

Group
entry
descriptions
for
entries
to
be
created




errors

A
sequence
of
structs
reporting
the
items
that
were
not
entered
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
UNKNOWN
PATHNAME
•
ERROR
BAD
TYPE
•
ERROR
UNKNOWN
ACCESS
PATH



return

A
sequence
of
result
descriptions
for
the
entries
that
were
entered
in
the
group




validate
entries



Is
used
to
determine
if
an
item
is
valid

could
it
be
added
without
error


Also
returns
information
about
the
item
such
as
canonical
datatype

Does
not
affect
the
group
in
any
way




Parameter

Description



entries

Group
entry
descriptions
for
entries
to
be
validated




errors

A
sequence
of
structs
reporting
the
items
that
could
not
be
validated
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
UNKNOWN
PATHNAME
•
ERROR
BAD
TYPE
•
ERROR
UNKNOWN
ACCESS
PATH



return

A
sequence
of
result
descriptions
for
the
entries
that
were
validated




remove
entries



Used
to
remove
entries
from
a
group




Parameter

Description



server
handles

Server
handles
for
entries
that
shall
be
removed




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
removed
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
active
state



Used
to
activate
individual
items
in
a
group

Activate
state
means
that
the
server
acquires
data
from
devices

Inactive
state
means
that
the
server
does
not
acquire
any
data

The
group
enable
state
control
if
acquired
data
shall
be
sent
further
to
subscribers
via
on
data
change




Parameter

Description



server
handles

Server
handles
for
items
to
activate




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
activated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
inactive
state



Used
to
deactivate
individual
items
in
a
group




Parameter

Description



server
handles

Server
handles
for
items
to
deactivate




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
deactivated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
client
handles



Used
to
change
the
client
handles
for
items




Parameter

Description



handle
associations

Change
descriptions
for
the
items
where
to
change
the
client
handles




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
updated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
data
types



Used
to
change
the
requested
data
types
for
items




Parameter

Description



descriptions

Change
descriptions
for
the
items
where
to
change
the
data
types




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
updated
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
BAD
TYPE



create
group
entry
iterator



Used
to
create
a
group
entry
iterator

Used
by
clients
to
inspect
existing
group
entries




Parameter
Description
return
The
GroupEntry
Iterator


















A
group
is
a
collection
of
items
and
a
connection
to
one
or
more
consumers
of
item
values

Clients
create
groups
and
their
lifetime
is
bounded
by
the
session
to
which
they
belong


See

Section
4
2
2

“DAISDASession
IDL
?
on
page
4-8




The
purpose
of
a
group
is
to
convey
selected
item
values
to
a
client

A
callback
object

may
be
connected
to
a
group
to
receive
item
value
information

see
Section
4
2
5


“DAISDAIO
IDL
?
on
page
4-23


Items
may
be
added
and
removed
from
a
group
as

group
entries

see

Section
4
2
6

“DAISGroupEntry
IDL
?
on
page
4-32


A
group
has
an

update
rate
that
determines
how
frequently
updated
values
for
its
entries
are
notified
to
its
connected
callback
objects

A
group
also
has
other
states
that
control
its
notification
behavior


A
group
may
also
be
initialized
with
a
predefined
set
of
entries

A
set
of
entries
is
called
a
public
group
and
is
identified
by
a
ResourceID

A
client
can
create
or
remove
public
groups

A
server
may
represent
a
public
group
as
a
node
such
that
the
ResourceID
of
the
public
group
and
the
node
are
identical

This
would
allow
clients
to
locate
public
groups
by
name


The
DAIS


DataAccess

Group

Manager
object
implements
interfaces
from
the
DAISDAIO
and
DAISGroupEntry
IDLs

This
is
specified
by
inheritance
of
interfaces
as
seen
in

Figure
4-14


A
DAIS

DataAccess

Group

Manager
has
a
state
given
by
the
DAIS

DataAccess

Group

State
struct
and
a
DAIS

DataAccess

Group

Manager
object
is
created
from
the
DAIS

DataAccess

Group

IHome
object


In
OPC
the
Group
interface
corresponds
to
the
interfaces
IOPCGroupStateMgt
and
IOPCPublicGroupStateMgt




DAIS

DataAccess

IO

ConnectionPoint

from
DAISDAIO

<<Interface>>
callback




DAIS

DataAccess

IO

Callback
callback
callback


DAIS

DataAccess

IO

Callback




11



0

10

1



DAIS

DataAccess

IO

Callback

from
DAISDAIO

<<Interface>>



DAIS

DataAccess

IO

SyncIO

from
DAISDAIO

<<Interface>>
sync
read


sync
write


DAIS

DataAccess

IO

AsyncIO

fromDAISDAIO

<<Interface>>
async
read


async
write


refresh


cancel


set
enable


get
enable


DAIS

DataAccess

GroupEntry

Manager

from
DAISGrou
pEntry

<<Interface>>
create
entries


validate
entries


remove
entries


set
active
state


set
inactive
state


set
client
handles


set
data
types


create
group
entry
iterator





DAIS

DataAccess

GroupEntry

Iterator

from
DAISGroupEntry

<<Interface>>



0

*0

*


11



DAIS

DataAccess

Group

Manager
<<Interface>>
get
state


set
state


clone


clone
group
to
public


destroy





0

n0

n



11



DAIS

DataAccess

Group

IHome
<<Interface>>
find
public
groups


find


create
group


clone
group
from
public


remove
public
group





11



11



DAIS

DataAccess

Group

State
update
rate


unsigned
long
active


boolean
time
bias


long
percent
dead
band


double
locale
id


unsigned
long
name


string

Figure
4-14
DAIS
data
access
group
IDL
in
UML











File

DAISGroup
idl
#ifndef

DAIS
GROUP
IDL
#define

DAIS
GROUP
IDL
#pragma
prefix
"omg
org"

#include
<DAISCommon
idl>
#include
<DAISGroupEntry
idl>
#include
<DAISDAIO
idl>

module
DAIS
{
module
DataAccess
{
module
Group
{

exception
DuplicateName
{string
reason
}


struct
State
{




string

name





unsigned
long

update
rate





boolean

active





long

time
bias





double

percent
deadband





unsigned
long

locale
id




}






struct
PublicGroupDescription

{
ResourceID
id

State
group
state


}

typedef
sequence<PublicGroupDescription>PublicGroupDescriptions


interface
Manager


GroupEntry

Manager

IO

AsyncIO

IO

SyncIO

IO

ConnectionPoint

{

State
get
state





unsigned
long
set
state


in
State
group
state


raises

DuplicateName



Manager
clone


in
string
name


raises

DuplicateName



PublicGroupDescription
clone
group
to
public


in
string
name


raises

DuplicateName



void
destroy




}

interface
IHome
{

exception
UnknownResourceID
{string
reason
}


PublicGroupDescriptions
find
public
groups




PublicGroupDescription
find

in
ResourceID
public
group


raises

UnknownResourceID


Manager
create
group



in
State
group
state


out
unsigned
long
revised
update
rate



raises

DuplicateName



Manager
clone
group
from
public



in
ResourceID
public
group


in
string
name



raises

DuplicateName

UnknownResourceID



void
remove
public
group



in
ResourceID
public
group



raises

UnknownResourceID


}
}
}
}

#endif




DAIS
GROUP
IDL

DuplicateName

An
exception
raised
when
an
object
is
created
and
the
name
already
exists

No
object
is
created
if
the
exception
is
raised

Used
for
session
and
group
manager
objects


State

The
struct
contains
information
about
the
group
state




Members

Description



name

Within
the
session
and
public
groups

unique
name
of
the
group




update
rate

Update
rate
for
the
group
in
milliseconds

When
used
as
input
it
specifies
the
fastest
rate
at
which
data
changes
may
be
sent
to
on
data
change


for
items
in
this
group

This
also
indicates
the
desired
accuracy
of
cached
data

This
is
intended
only
to
control
the
behavior
at
the
interface

How
the
server
deals
with
the
update
rate
and
how
often
it
actually
polls
the
hardware
internally
is
an
implementation
detail

Passing
0
indicates
the
server
should
use
the
fastest
practical
rate






active

Indicates
if
the
group
is
active
and
data
from
devices
is
updated
in
the
cache




time
bias

The
time
bias
in
minutes
for
the
group

A
zero
value
when
used
as
input
will
tell
the
server
to
use
the
default
system
time
bias

This
bias
behaves
like
the
Bias
field
in
the
Win32
TIME
ZONE
INFORMATION
structure




percent
deadband

The
percent
change
for
an
item
value
that
will
cause
a
call
back
for
that
value

This
parameter
only
applies
to
items
in
the
group
that
are
of
analog
type

If
a
client
specifies
a
zero
deadband

the
value
will
be
reported
with
the
update
rate




locale
id

The
localization
number
for
the
language
used
when
returning
string
values




Manager

An
object
used
to
manage
a
group

It
has
a
set
of
methods
related
to
the
group
itself

It
also
inherits
methods
from
interfaces
for
group
entry
management
and
data
transfer

For

group
entry
management
refer
to
Section
4
2
6

“DAISGroupEntry
IDL
?
on
page
4-32

and
for
data
transfer
refer
to

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15

The

DAIS

DataAccess

Group

Manager
interface
corresponds
to
the
IOPCGroupStateMgt
interface


get
state



The
method
gets
the
group
status




Parameter
Description
return
State

set
state



The
method
sets
the
group
status




Parameter

Description



group
state

The
State
with
the
updates

All
members
will
be
updated

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
update
is
made




return

The
closest
update
rate
the
server
is
able
to
provide
for
the
group




clone



Create
a
copy
of
a
group




Parameter

Description



name

The
name
to
be
given
for
the
new
group

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
clone
is
created




return

A
description
of
the
public
group




clone
group
to
public




Create
a
public
copy
of
a
group
including
all
items
and
the
group
state




Parameter

Description



name

The
name
to
be
given
for
the
new
group

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
public
group
is
created




return

A
description
of
the
public
group




destroy



Delete
the
group


PublicGroupDescription

A
struct
describing
public
groups




Member

Description



id

A
ResourceID
identifying
the
public
group




group
state

The
group
state
struct
including
the
group
name




IHome

The
factory
object
for
groups

The
corresponding
OPC
interface
is
IOPCServer


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

For
methods
taking
a
sequence
of
resource
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find
public
groups



Find
all
public
groups
defined
in
the
server




Member
Description
return
A
sequence
of
public
group
descriptions


find



For
a
given
public
group

return
information
about
that
group




Member

Description



public
group

A
ResourceID
identifying
the
public
group




return

A
public
group
description




create
group



Create
a
new
initially
empty
group




Parameter

Description



group
state

The
State
to
be
set
for
the
new
group




revised
update
rate

The
closest
update
rate
the
server
is
able
to
provide
for
the
group




return

The
new
group




clone
group
from
public



Create
a
copy
from
a
public
group
having
an
existing
set
of
entries
and
state




Parameter

Description



public
group

The
identification
of
the
public
group




name

The
name
of
the
new
group




return

The
new
group




remove
public
group



Remove
a
public
group




Parameter

Description



public
group

The
identification
of
the
public
group




return

None



Group
management





Client
Client


DAIS

DataAccess

Session

DAIS

DataAcce
Grup

IHome
Gss

Session


DAIS

DataAccess
o

DAIS

DataAccess
roup

IHome


DAIS

DataAccess

Group

Manager

DAIS

DataAccess

Group

Managergroup
home



create
group



create
entries



Do
work
with
group
manager

e
g

activate
subscription
destroy




Figure
4-15
Group
management
interaction

Activate
subscription





Client

Client


DAIS

DataAccess

Group

Manager
DAIS

DataAccess

Group

Managerss
IO

Callbacks

DAIS

DataAcce

DAIS

DataAcces

IO

Callbackcallback
DAISDACallback

refresh



on
data
change



Forced
by
refresh
on
data
change



Spontaneous
on
data
change



Spontaneous

Figure
4-16
Active
subscription
interaction
Activate
a
subscription
silently





Client

Client


DAIS

DataAccess

Group

Manager

DAIS

DataAccess

Group

Managerss
IO

Callbacks

DAIS

DataAcce


DAIS

DataAcces

IO

Callbackset
inactive
state



callback



set
enable



set
active
state



Disable
refresh



on
data
change



set
enable



Enable
on
data
change




Figure
4-17
Activate
a
subscription
silently
interaction
Cancel





DAIS

DataAccess

Group

M
anager
DAIS

DataAccess

Group

Manager


DAIS

DataAccess

IO

Callback

DAIS

DataAccess

IO

CallbackCancel
refresh
operation
Cancel
async
read
Cancel
async
write


Client

Clienton
cancel
complete



on
cancel
complete



on
cancel
complete




refresh




cancel




async
read




cancel




async
write




cancel




Figure
4-18
Cancellation
interaction

















The
purpose
of
the
interface
is
to
provide
a
simple
read
and
write
of
data

The
functionality
is
the
same
as
the
synchronous
read
and
write
described
in

Section
4
2
5


“DAISDAIO
IDL
?
on
page
4-23

but
without
having
to
create
a
group












File

DAISDASimpleIO
idl#ifndef

DAIS
DA
SIMPLE
IO
IDL#define

DAIS
DA
SIMPLE
IO
IDL#include
<DAISCommon
idl>
module
DAIS
{module
DataAccess
{module
SimpleIO
{
enum
DataSource
{


DS
CACHE



DS
DEVICE

}


struct
ItemError
{



}

typ
Error
ServerItemIdentification
string
edef
sequence<ItemError>

err

id

reason

ItemErrors




{
str
uct
ItemState





SimpleValue
DateTime
Quality
ServerItemIdentification

value

time
stamp

dais
quality

id




}






typedef
sequence<ItemState>ItemStates


struct
ItemUpdate

{
ServerItemIdentification
id

SimpleValue
value


}
typedef
sequence<ItemUpdate>
ItemUpdates

interface
IHome
{
ItemStates
read


in
DataSource
data
source

in
ServerItemIdentifications
ids

out
ItemErrors
errors





ItemErrors
write
with
qt


in
ItemStates
updates




ItemErrors
write


in
ItemUpdates
updates




}
}
}
}

#endif




DAIS
DA
SIMPLE
IO
IDL
DataSource

Find
all
public
groups
defined
in
the
server




Member

Description



DS
CACHE

Data
cached
in
the
server
is
requested




DS
DEVICE

Data
from
the
device
is
requested

This
will
force
a
read
from
the
device
or
RTU

A
read
from
device
will
be
made
regardless
of
the
group
or
item
active
status
and
no
group
NotActive
exception
will
be
forced




ItemError

A
struct
for
reporting
of
item
related
errors

The
struct
is
different
from
the
DAIS

ItemError
because
no
handles
are
used
to
identify
the
item
in
SimpleIO




Member

Description



err

An
error
code
as
described
for
DAIS

ItemError




id

The
identification
of
the
item




reason

An
additional
text
explaining
the
error




ItemState

The
struct
is
the
carrier
of
data
conveyed
over
the
interface

It
is
the
“message?
holding
the
payload

This
is
basically
the
same
struct
as
DataAccess

IO

ItemState
with
the
difference
that
instead
of
a
handle
for
identification
the
full
server
identification
is
used




Member

Description



value

The
value
itself




time
stamp

The
time
stamp
when
the
value
was
last
updated




quality

The
quality
for
the
value




id

The
identification
of
the
value
in
the
server




ItemUpdate

The
struct
carries
an
update
for
an
item




Member

Description



id

The
identification
of
the
value
in
the
server




value

The
value
that
shall
be
used
in
the
update




IHome

The
interface
for
simple
IO
operations


read

Synchronous
read
of
items

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




Parameter

Description



data
source

The
source
from
where
to
read
the
data

see
DataSource
above




ids

A
sequence
specifying
the
server
identifications
to
read




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID



return

A
sequence
of
ItemStates
for
the
items




write
with
qt

Synchronous
write
of
item
values
including
quality
and
time
stamp

The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemStates
specifying
the
updates
including
time
stamp
and
quality




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



write

Synchronous
write
of
item
values
only

The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
the
update
values




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE











Equipment
in
any
industrial
process
is
usually
modeled
as
entities
or
classes
in
computerized
systems

The
class
name
usually
reflects
the
type
of
equipment

Objects
from
such
classes
are
called
Real
World
Objects

RWOs

in
this
document

RWO
classes
have
properties
describing
equipment
characteristics

for
example

size

length

geometries

material

nameplate
data

as
well
as
application
specific
data

for
example

impedance
parameters

state
estimated
values


Depending
on
the
purpose
of
a
system
and
the
managed

industrial

process
the
RWOs
are
of
different
types
and
contain
different
properties

Some
RWOs
are
common
between
systems
and
independent
of
industrial
process
like
process
variables

that
is

measurement

state

and
control
variables

Other
RWOs
like
transmission
lines
and
breakers
are
specific
to
power
transmission


RWO
will
typically
have
properties
depending
on
the
RWO
type

for
example

measurement

transformer

and
what
application
or
usage
the
RWO
is
involved
in

Properties
are
defined
per
type
of
RWO







In
DAIS
RWOs
are
represented
by
Nodes

Property
instances
at
a
node
are
represented
by
Items

An
item
may
represent
a
measurement
value

a
control
output
value

or
any
parameter

for
example

a
limit
value

a
unit

a
name

a
description


A
Type
and
properties
belonging
to
a
type
represent
an
RWO
type
by
DAISProperties

Nodes
are
hierarchically
structured
and
the
leafs
are
Items

This
is
shown

in
Figure
4-1





Instance
data

nodes
and
items
Meta
data

data
about
nodes
and
items
Item
cache
value


S
impleV
alue
cache
value
last
updated


DateTime
cache
value
quality


DAIS

Quality
scan
rate


uns
igned
long
access

rights


DAIS

Acc
essRights

from
DAISItem

Property
id


PropertyID
label


string
description


string
canonical
data
type


S
impleValueType

from
DAISProperty

0

n01


n+property
1Type
id


ResourceID
schema


ResourceID
label


string
description


string

f
rom
DAI
STy
pe

0

n0
1

n

n1

n0

n0
+aggregated
types

nNode
id


Resourc
eID
label


s
tring
type


ResourceID

from
DAISNode

1
0

n
+type
10

nNodeItemComponent
pathname


string

from
DAISNode

1
0

*
+parent
10

*
Figure
4-1
DAIS
data
access
server
information
model

The
Component
class
inherited
by
the
Node
and
Item
classes
models
the
hierarchical
structure

The
Node
may
contain
any
number
of
Components
as
described
by
the
Contains
role
having
the
cardinality
many

role
is
a
UML
concept

refer
to
[9]
for
an
explanation


A
Component
is
a
member
of
one
Node
as
described
by
the
MemberOf
role
having
the
cardinality
of
1

A
Component
can
be
both
a
Node
and
an
Item
through
the
inheritance

which
means
a
Node
can
contain
other
Nodes
or
Items

An
Item
cannot
contain
any
Components
as
it
only
inherits
the
MemberOf
role
and
not
the
Contains
role










Node
and
item
names
follow
OPC
[4]
and
IEC
1346-1
[10]

Each
Node
has
a
label
unique
among
other
Nodes
having
the
same
parent

that
is

are
MemberOf
the
same
Node

An
Item
does
not
have
an
own
label
but
uses
the
label
from
the
Property

Each
Item
in
a
Node
is
associated
with
different
DAISProperties
so
that
the
label
is
unique
among
other
items
at
the
same
node

The
labels
in
the
path
from
an
item
or
node
to
the

root
form
a
pathname

Labels
and
pathnames
are
explained
in
Figure
4-2





Root



label
=
Ceylon
pathname
=
Ceylon
type
=
Station



label
=
Cobden
pathname
=
Cobden
type
=
Station
label
=
Q1
pathname
=
Cobden
Q1
type
=
Breaker
label
=
G1
pathname
=
Cobden
G1
type
=
Generator
label
=
P
pathname
=
Cobden
G1
P
type
=
Measurement

A
Node



An
Item



label
=
ActivePower
pathname
=
Cobden
G1
P
ActivePower
value
=
50
time
stamp
=
2000-11-17
14
28
05
quality
=
Good
label
=
Unit
pathname
=
Cobden
G1
P
Unit
value
=
MW
time
stamp
=
2000-11-17
14
28
05
quality
=
Good
label
=
HighLimit
pathname
=
Cobden
G1
P

HighLimit
value
=
MW
time
stamp
=
2000-11-17
14
28
05
quality
=
Good

Figure
4-2
Labels
and
pathnames

A
delimiter

the
label
delimiter

might
separate
the
labels
in
a
pathname

Assuming
the
label
delimiter
is
a
“
?
An
example
of
an
item
pathname
for
a
measurement
value
in

Figure
4-2
is


Cobden
G1
P
Value
where
the
labels
are




•	
station

Cobden



•	
generator

G1



•	
active
power
measurement


P



•	
the
actual
measurement
value
property

Value



Exactly
how
the
pathname
is
composed
from
the
labels
is
server
specific
and
outside
the
scope
of
this
specification










Items
are
associated
with
values

Typically
an
item
value
provided
by
a
DAIS
server
is
read
from
a
device
and
transferred
to
one
or
more
clients

In
a
distributed
control
system

involving
remote
devices

as
indicated
in
Figure
4-3

communication
failures
might

make
item
values
not
available

To
cope
with
communication
failures
item
values
are
associated
with
a
quality

The
quality
indicates
the
reliability
of
the
item
value

Devices
usually
scan
item
values
at
a
certain
rate
and
item
values
will
be
transferred
to
the
DAIS
server
at
this
rate
or
some
other

In
the
server

item
values
will
appear
as
time
stamped
and
quality
coded
samples

A
server
that
keeps
item
values
in
a
local
cache
is
expected
to
always
hold
the
latest
sample

Other
item
related
informations
are
access-rights
and

scan-rate

This
information
is
shown
in
Figure
4-4

The
cache
value
is
the
latest
sample

received
from
a
device

the
cache
value
last
updated
the
time
when
the
cache
value
was
last
updated
or
validated

and
cache
value
quality
when
the
value
was
last
updated
or
validated


For
items

a
DAIS
server
exposes
the
following
information
to
clients




•	
the
value
and
its
data
type




•	
the
quality
of
the
value




•	
the
time
stamp
for
the
value




•	
the
fastest
scan
rate
with
which
the
value
can
be
expected
to
be
updated

and




•	
the
access
rights



To
make
access
of
item
values
efficient
and
avoid
reading
the
values
from
devices
each
time
a
client
requests
item
values

a
DAIS
server
is
expected
to
have
a
local
cache

The
mechanism
for
keeping
the
cache
up
to
date
is
server
specific
but
a
client
shall
expect
the
following
from
the
server




•	
Values
delivered
from
the
cache
reflect
the
latest
value
considering
update
rate
and
update
dead
bands

Based
on
the
agreed
update
rate

between
a
client
and
a
server

a
client
can
expect
that
the
server
will
validate
the
values
with
devices
with
the
agreed
update
rate




•	
The
dead
band
is
expected
to
be
checked
at
each
update
or
validation

Values
that
don’t
transgress
the
deadband
will
not
be
reported




•	
Time
stamps
delivered
from
the
cache
shall
reflect
when
the
values
were
updated
or
validated
with
the
devices
according
to
the
agreed
update
rate

The
time
stamp
gives
the
time
for
the
latest
successful
update
or
validation




•	
The
quality
shall
reflect
how
successful
the
server
has
been
in
keeping
the
values
updated
or
validated












DAIS
is
flexible
in
terms
of
what
types
and
properties
may
exist
in
a
server


In
OPC
there
is
a
recommendation
of
what
properties
are
expected
to
be
supported
by
a
data
access
server

These
recommended
properties
are
shown
in

Table
4-1

The
column

names
correspond
to
the
attributes
in
the
Property
class
seen
in
Figure
4-4



Table
4-1
Recommended
Properties



label

id

canonical
data

type

description



engineeringUnit

100

STRING
TYPE

Engineering
unit




description

101

STRING
TYPE

Description




maxValue

102

DOUBLE
TYPE

Maximum
value




minValue

103

DOUBLE
TYPE

Minimum
value




sensorMaximum

104

DOUBLE
TYPE

Maximum
value
from
an
analog
input
sensor




sensorMinimum

105

DOUBLE
TYPE

Minimum
value
from
an
analog
input
sensor




closedLabel

106

STRING
TYPE

Text
for
the
closed
state
for
a
discrete
status
input




openLabel

107

STRING
TYPE

Text
for
the
open
state
for
a
discrete
status
input




itemTimeZone

108

UNSIGNED
TYPE





109-4999


Reserved
by
OPC




For
a
system
having
data
described
by
a
particular
schema

for
example

the
CIM
for
power
systems

the
implementation
of
that
schema
as
seen
through
DAIS
has
to
be
decided

Either
a
mapping
to
the
recommended
OPC
properties
can
be
made
or
the
schema
can
be
exposed
as
is
through
DAIS

This
is
however
outside
the
scope
of
this
specification










The
classes
and
properties
defined
in
the
IEC
61970-30x

the
CIM

can
be
mapped
onto
the
OPC
recommended
properties

As
the
CIM
is
highly
structured

this
will
create
a
complicated
mapping

An
alternative
is
to
expose
CIM
as
is
through
the
DAIS

This
means
that
the
CIM
classes
and
their
properties
will
appear
the
same
as
seen
through
the
DAIS
as
through
the
DAF
interfaces

As
the
DAIS
requires
a
hierarchical
structuring
of
nodes

the
CIM
equipment
hierarchy
is
selected
as
the
hierarchy
exposed
through
the
DAIS


Besides
the
equipment
hierarchy
the
CIM
also
has
a
number
of
other
associations

Such
associations
may
be
made
visible
through
the
DAIS
interface
as
properties
holding
ResourceIDs


The
CIM
has
several
associations
between
RWOs
and
ways
to
structure
RWOs

The
requirement
from
DAIS
on
the
equipment
hierarchy
is
that
it
is
strictly
hierarchical

else
DAIS
is
transparent
to
any
information
model


For
RWOs
in
the
equipment
hierarchy
its
properties
simply
appear
as
items
at
the
nodes
representing
the
RWOs

The
DAIS
supports
navigating
across
associations
as
ResourceIDs
can
be
conveyed
by
SimpleValues


Utility
SCADA
EMS
systems
have
a
number
of
different
applications
calculating
alternate
measurement
values

In
the
IEC61970
draft
standard
this
is
modeled
by
Measurements
containing
one
or
more
MeasurementValues

as

shown
in
Figure
4-3





Limit
value
Lim
itSet
0
*
0

*1Measurement
<<RWO>>
0
*
0
+LimitSets

*1MeasurementValueSource
name
MeasurementV
alue
value
<<RWO>>
1
*
1

*1+MeasurementValueSource
1
Figure
4-3
Utility
SCADA
Measurement
Modeling

The
Measurement
and
the
MeasurementValue
appear
as
Nodes
and
their
properties
as
Items

In
the
example
from

Section
4
1
2

“Naming
?
on
page
4-3

th
e
Measurement
again
is
represented
by
the
pathname


Cobden
G1
P

Moving
down
to
MeasurementValue
will
add
its
label
to
the
pathname
so
that
it
may
look
like


Cobden
G1
P
Telem

If
the
MeasurementValue
property
for
the
value
has
the
label
Value

finally
the
pathname
for
the
item
will
be


Cobden
16kV
G1
P
Telem
Value
In
a
system
also
having
a
State
Estimated
MeasurementValue

the
pathname
for
state
estimated
value
might
be


Cobden
16kV
G1
P
SE
Value
Finally
if
the
state
estimated
value
is
to
replace
the
telemetered

this
can
be
implemented
picking
the
“best?
MeasurementValue
from
Measurement
itself
shortcutting
the
MeasurementValue
resulting
in
the
path

Cobden
G1
P
Value
The
CIM
classes
that
shall
be
navigable
and
whose
data
is
exposed
through
DAIS
are
listed
in

Table
4-2



Table
4-2
CIM
Classes



CIM
class

Properties
and
references



Measurement

All



MeasurementValue

All

MeasurementValues
are
expected
to
appear
in
the
hierarchical
structure
so
that
all
MeasurementValue
instances
are
visible
in
the
browser




MeasurementUnit

All



LimitSet

All

The
Measurement
to
LimitSet
reference
has
a
cardinality
1

*

It
is
expected
that
one
LimitSet
is
the
current
used
and
exposed
through
DAIS




Limit

As
the
LimitSet
to
Limit
reference
has
the
cardinality
1

*
the
mapping
through
DAIS
is
expected
to
be
a
number
of
properties
where
each
property
corresponds
to
one
limit
value




ValueAliasSet

As
the
ValueAliasSet
to
ValueToAlias
reference
has
cardinality
1

*
the
mapping
through
DAIS
is
expected
to
be
a
number
of
properties
where
each
property
corresponds
to
one
translation
from
numeric
to
symbolic
value




Classes
in
the
hierarchical
structure
above
Measurement


An
implementation
is
free
to
expose
any
hierarchical
structure
of
classes
above
the
Measurement

Multiple
and
different
structures
are
allowed
using
different
views

for
views
refer
to
Section
3
2
2

“DAIS
Server
IDL
?
on
page
3-30


An
implementation
is
also
free
to
expose
any
properties
from
these
classes





The
table
is
based
on
the
CIM
version
given
by
[11]












In
DAIS
RWOs
are
represented
by
Nodes

Property
instances
at
a
node
are
represented
by
Items

An
item
may
represent
a
measurement
value

a
control
output
value

or
any
parameter

for
example

a
limit
value

a
unit

a
name

a
description


A
Type
and
properties
belonging
to
a
type
represent
an
RWO
type
by
DAISProperties

Nodes
are
hierarchically
structured
and
the
leafs
are
Items

This
is
shown

in
Figure
4-1





Instance
data

nodes
and
items
Meta
data

data
about
nodes
and
items
Item
cache
value


S
impleV
alue
cache
value
last
updated


DateTime
cache
value
quality


DAIS

Quality
scan
rate


uns
igned
long
access

rights


DAIS

Acc
essRights

from
DAISItem

Property
id


PropertyID
label


string
description


string
canonical
data
type


S
impleValueType

from
DAISProperty

0

n01


n+property
1Type
id


ResourceID
schema


ResourceID
label


string
description


string

f
rom
DAI
STy
pe

0

n0
1

n

n1

n0

n0
+aggregated
types

nNode
id


Resourc
eID
label


s
tring
type


ResourceID

from
DAISNode

1
0

n
+type
10

nNodeItemComponent
pathname


string

from
DAISNode

1
0

*
+parent
10

*
Figure
4-1
DAIS
data
access
server
information
model

The
Component
class
inherited
by
the
Node
and
Item
classes
models
the
hierarchical
structure

The
Node
may
contain
any
number
of
Components
as
described
by
the
Contains
role
having
the
cardinality
many

role
is
a
UML
concept

refer
to
[9]
for
an
explanation


A
Component
is
a
member
of
one
Node
as
described
by
the
MemberOf
role
having
the
cardinality
of
1

A
Component
can
be
both
a
Node
and
an
Item
through
the
inheritance

which
means
a
Node
can
contain
other
Nodes
or
Items

An
Item
cannot
contain
any
Components
as
it
only
inherits
the
MemberOf
role
and
not
the
Contains
role









Node
and
item
names
follow
OPC
[4]
and
IEC
1346-1
[10]

Each
Node
has
a
label
unique
among
other
Nodes
having
the
same
parent

that
is

are
MemberOf
the
same
Node

An
Item
does
not
have
an
own
label
but
uses
the
label
from
the
Property

Each
Item
in
a
Node
is
associated
with
different
DAISProperties
so
that
the
label
is
unique
among
other
items
at
the
same
node

The
labels
in
the
path
from
an
item
or
node
to
the

root
form
a
pathname

Labels
and
pathnames
are
explained
in
Figure
4-2





Root



label
=
Ceylon
pathname
=
Ceylon
type
=
Station



label
=
Cobden
pathname
=
Cobden
type
=
Station
label
=
Q1
pathname
=
Cobden
Q1
type
=
Breaker
label
=
G1
pathname
=
Cobden
G1
type
=
Generator
label
=
P
pathname
=
Cobden
G1
P
type
=
Measurement

A
Node



An
Item



label
=
ActivePower
pathname
=
Cobden
G1
P
ActivePower
value
=
50
time
stamp
=
2000-11-17
14
28
05
quality
=
Good
label
=
Unit
pathname
=
Cobden
G1
P
Unit
value
=
MW
time
stamp
=
2000-11-17
14
28
05
quality
=
Good
label
=
HighLimit
pathname
=
Cobden
G1
P

HighLimit
value
=
MW
time
stamp
=
2000-11-17
14
28
05
quality
=
Good

Figure
4-2
Labels
and
pathnames

A
delimiter

the
label
delimiter

might
separate
the
labels
in
a
pathname

Assuming
the
label
delimiter
is
a
“
?
An
example
of
an
item
pathname
for
a
measurement
value
in

Figure
4-2
is


Cobden
G1
P
Value
where
the
labels
are




•	
station

Cobden



•	
generator

G1



•	
active
power
measurement


P



•	
the
actual
measurement
value
property

Value



Exactly
how
the
pathname
is
composed
from
the
labels
is
server
specific
and
outside
the
scope
of
this
specification









Items
are
associated
with
values

Typically
an
item
value
provided
by
a
DAIS
server
is
read
from
a
device
and
transferred
to
one
or
more
clients

In
a
distributed
control
system

involving
remote
devices

as
indicated
in
Figure
4-3

communication
failures
might

make
item
values
not
available

To
cope
with
communication
failures
item
values
are
associated
with
a
quality

The
quality
indicates
the
reliability
of
the
item
value

Devices
usually
scan
item
values
at
a
certain
rate
and
item
values
will
be
transferred
to
the
DAIS
server
at
this
rate
or
some
other

In
the
server

item
values
will
appear
as
time
stamped
and
quality
coded
samples

A
server
that
keeps
item
values
in
a
local
cache
is
expected
to
always
hold
the
latest
sample

Other
item
related
informations
are
access-rights
and

scan-rate

This
information
is
shown
in
Figure
4-4

The
cache
value
is
the
latest
sample

received
from
a
device

the
cache
value
last
updated
the
time
when
the
cache
value
was
last
updated
or
validated

and
cache
value
quality
when
the
value
was
last
updated
or
validated


For
items

a
DAIS
server
exposes
the
following
information
to
clients




•	
the
value
and
its
data
type




•	
the
quality
of
the
value




•	
the
time
stamp
for
the
value




•	
the
fastest
scan
rate
with
which
the
value
can
be
expected
to
be
updated

and




•	
the
access
rights



To
make
access
of
item
values
efficient
and
avoid
reading
the
values
from
devices
each
time
a
client
requests
item
values

a
DAIS
server
is
expected
to
have
a
local
cache

The
mechanism
for
keeping
the
cache
up
to
date
is
server
specific
but
a
client
shall
expect
the
following
from
the
server




•	
Values
delivered
from
the
cache
reflect
the
latest
value
considering
update
rate
and
update
dead
bands

Based
on
the
agreed
update
rate

between
a
client
and
a
server

a
client
can
expect
that
the
server
will
validate
the
values
with
devices
with
the
agreed
update
rate




•	
The
dead
band
is
expected
to
be
checked
at
each
update
or
validation

Values
that
don’t
transgress
the
deadband
will
not
be
reported




•	
Time
stamps
delivered
from
the
cache
shall
reflect
when
the
values
were
updated
or
validated
with
the
devices
according
to
the
agreed
update
rate

The
time
stamp
gives
the
time
for
the
latest
successful
update
or
validation




•	
The
quality
shall
reflect
how
successful
the
server
has
been
in
keeping
the
values
updated
or
validated











DAIS
is
flexible
in
terms
of
what
types
and
properties
may
exist
in
a
server


In
OPC
there
is
a
recommendation
of
what
properties
are
expected
to
be
supported
by
a
data
access
server

These
recommended
properties
are
shown
in

Table
4-1

The
column

names
correspond
to
the
attributes
in
the
Property
class
seen
in
Figure
4-4



Table
4-1
Recommended
Properties



label

id

canonical
data

type

description



engineeringUnit

100

STRING
TYPE

Engineering
unit




description

101

STRING
TYPE

Description




maxValue

102

DOUBLE
TYPE

Maximum
value




minValue

103

DOUBLE
TYPE

Minimum
value




sensorMaximum

104

DOUBLE
TYPE

Maximum
value
from
an
analog
input
sensor




sensorMinimum

105

DOUBLE
TYPE

Minimum
value
from
an
analog
input
sensor




closedLabel

106

STRING
TYPE

Text
for
the
closed
state
for
a
discrete
status
input




openLabel

107

STRING
TYPE

Text
for
the
open
state
for
a
discrete
status
input




itemTimeZone

108

UNSIGNED
TYPE





109-4999


Reserved
by
OPC




For
a
system
having
data
described
by
a
particular
schema

for
example

the
CIM
for
power
systems

the
implementation
of
that
schema
as
seen
through
DAIS
has
to
be
decided

Either
a
mapping
to
the
recommended
OPC
properties
can
be
made
or
the
schema
can
be
exposed
as
is
through
DAIS

This
is
however
outside
the
scope
of
this
specification









The
classes
and
properties
defined
in
the
IEC
61970-30x

the
CIM

can
be
mapped
onto
the
OPC
recommended
properties

As
the
CIM
is
highly
structured

this
will
create
a
complicated
mapping

An
alternative
is
to
expose
CIM
as
is
through
the
DAIS

This
means
that
the
CIM
classes
and
their
properties
will
appear
the
same
as
seen
through
the
DAIS
as
through
the
DAF
interfaces

As
the
DAIS
requires
a
hierarchical
structuring
of
nodes

the
CIM
equipment
hierarchy
is
selected
as
the
hierarchy
exposed
through
the
DAIS


Besides
the
equipment
hierarchy
the
CIM
also
has
a
number
of
other
associations

Such
associations
may
be
made
visible
through
the
DAIS
interface
as
properties
holding
ResourceIDs


The
CIM
has
several
associations
between
RWOs
and
ways
to
structure
RWOs

The
requirement
from
DAIS
on
the
equipment
hierarchy
is
that
it
is
strictly
hierarchical

else
DAIS
is
transparent
to
any
information
model


For
RWOs
in
the
equipment
hierarchy
its
properties
simply
appear
as
items
at
the
nodes
representing
the
RWOs

The
DAIS
supports
navigating
across
associations
as
ResourceIDs
can
be
conveyed
by
SimpleValues


Utility
SCADA
EMS
systems
have
a
number
of
different
applications
calculating
alternate
measurement
values

In
the
IEC61970
draft
standard
this
is
modeled
by
Measurements
containing
one
or
more
MeasurementValues

as

shown
in
Figure
4-3





Limit
value
Lim
itSet
0
*
0

*1Measurement
<<RWO>>
0
*
0
+LimitSets

*1MeasurementValueSource
name
MeasurementV
alue
value
<<RWO>>
1
*
1

*1+MeasurementValueSource
1
Figure
4-3
Utility
SCADA
Measurement
Modeling

The
Measurement
and
the
MeasurementValue
appear
as
Nodes
and
their
properties
as
Items

In
the
example
from

Section
4
1
2

“Naming
?
on
page
4-3

th
e
Measurement
again
is
represented
by
the
pathname


Cobden
G1
P

Moving
down
to
MeasurementValue
will
add
its
label
to
the
pathname
so
that
it
may
look
like


Cobden
G1
P
Telem

If
the
MeasurementValue
property
for
the
value
has
the
label
Value

finally
the
pathname
for
the
item
will
be


Cobden
16kV
G1
P
Telem
Value
In
a
system
also
having
a
State
Estimated
MeasurementValue

the
pathname
for
state
estimated
value
might
be


Cobden
16kV
G1
P
SE
Value
Finally
if
the
state
estimated
value
is
to
replace
the
telemetered

this
can
be
implemented
picking
the
“best?
MeasurementValue
from
Measurement
itself
shortcutting
the
MeasurementValue
resulting
in
the
path

Cobden
G1
P
Value
The
CIM
classes
that
shall
be
navigable
and
whose
data
is
exposed
through
DAIS
are
listed
in

Table
4-2



Table
4-2
CIM
Classes



CIM
class

Properties
and
references



Measurement

All



MeasurementValue

All

MeasurementValues
are
expected
to
appear
in
the
hierarchical
structure
so
that
all
MeasurementValue
instances
are
visible
in
the
browser




MeasurementUnit

All



LimitSet

All

The
Measurement
to
LimitSet
reference
has
a
cardinality
1

*

It
is
expected
that
one
LimitSet
is
the
current
used
and
exposed
through
DAIS




Limit

As
the
LimitSet
to
Limit
reference
has
the
cardinality
1

*
the
mapping
through
DAIS
is
expected
to
be
a
number
of
properties
where
each
property
corresponds
to
one
limit
value




ValueAliasSet

As
the
ValueAliasSet
to
ValueToAlias
reference
has
cardinality
1

*
the
mapping
through
DAIS
is
expected
to
be
a
number
of
properties
where
each
property
corresponds
to
one
translation
from
numeric
to
symbolic
value




Classes
in
the
hierarchical
structure
above
Measurement


An
implementation
is
free
to
expose
any
hierarchical
structure
of
classes
above
the
Measurement

Multiple
and
different
structures
are
allowed
using
different
views

for
views
refer
to
Section
3
2
2

“DAIS
Server
IDL
?
on
page
3-30


An
implementation
is
also
free
to
expose
any
properties
from
these
classes





The
table
is
based
on
the
CIM
version
given
by
[11]















The
IDL
is
divided
into
files

Each
file
is
modeled
as
a
package
in
UML

A
file
that

depends
on
declarations
made
in
another
file
needs
to
include
it

Figure
4-4
shows
how

the
IDL
files
depend
on
each
other




DAISCommon

from
Common

DAISDAIO
DAISGroupEntry

DAISItem
DAISNode

from
Common

DAISProperty
DAISType

from
Common


from
Common


DAISGroup
DAISDASimpleIO



DAISDASession
DAISDANode
DAISSession

from
Common

DAISServer


from
Server


Figure
4-4
Dependencies
between
data
access
IDL
files















The
DAIS

DataAccess

Session
object
implements
the
data
access
service
on
a
per
client
basis

A
data
access
session
object
has
a
number
of
services
provided
by
one
singleton
home
object
each

Each
home
object
provides
methods
for
manipulation
of
the
data
of
the
specific
type
they
provide

Rather
than
exposing
data
as
objects
with
interfaces
it
is
exposed
as
structs
or
sequences
of
structs

The
reason
is
that
a
large
number
of
data
items
will
become
a
performance
bottleneck
if
instantiated
as
objects
over
an
interface

The
DAIS

Group

IHome
object
is
the
only
object
to
expose
its
data
as
objects

that
is

the
DAIS

Group

Manager

Each
DAIS

Group

Manager
is
expected
to
connect
to
one
callback
object
implemented
by
the
client


Each
client
may
instantiate
one
or
more
Sessions

The
Session
objects
have
one
Type
and
Property
Home
object
each

The
client
shall
expect
that
all
Type
and
Property
Home
objects
expose
the
same
types
and
properties


The
session
object
corresponds
to
an
OPCServer
object


1
0

1
10

1



DAIS

Session

from
DAISSess
ion

<<Interface>>
status




DAIS

SessionStatus
callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy


DAIS

DataAccess

Session
<<Interface>>
group
home




DAIS

DataAccess

Group

IHome
simple
io
home


DAIS

DataAccess

SimpleIO

IHome


node
home




DAIS

DataAccess

Node

IHome
item
home




DAIS

DataAccess

Item

IHome
type
home




DAIS

Type

IHome
property
home




DAIS

Property

IHome



DAIS

ShutdownCallback

from
DAISSessi
on

<<Interface>>



0

10

1



11



Client

fro
m
DAISServer




11



0

*0

*



11



DAIS

Type

IHome

f
rom
DAIST
ype

<<Interface>>



DAIS

DataAccess

IO

Callback

from
DAISDAIO

<<Interface>>






DAIS

Property

IHome

from
DAISProperty

<<Interface>>



0

10

1



11



11



11



DAIS

DataAccess

Node

IHome

from
DAISDANode


<<Interface>>



DAIS

DataAccess

IO

ConnectionPoint

from
DAISDAIO

<<Interface>>



11



DAIS

DataAccess

Group

IHome

from
DAISGroup

<<Interface>>
DAIS

DataAccess

Item

IHome

from
DAI
SItem

<<Interface>>






11

1
0



n

10




DAIS

DataAccess

Group

Manager

from
DAISGroup

<<Interface>>



11



DAIS

DataAccess

SimpleIO

IHome

from
DAISDASi
mp
leIO

<<Interface>>




Figure
4-5
DAIS
data
access
session
IDL
in
UML











File

DAISDASession
idl
#ifndef

DAIS
DA
SESSION
IDL
#define

DAIS
DA
SESSION
IDL
#pragma
prefix
"omg
org"






Common
Information
#include
<DAISNode
idl>
#include
<DAISProperty
idl>
#include
<DAISSession
idl>






Data
Access
interface
#include
<DAISType
idl>
#include
<DAISItem
idl>
#include
<DAISDANode
idl>
#include
<DAISGroup
idl>
#include
<DAISDASimpleIO
idl>



module
DAIS
{
module
DataAccess
{



interface
Session


DAIS

Session
{



readonly
attribute
Group

IHome

group
home




readonly
attribute
SimpleIO

IHome

simple
io
home




readonly
attribute
Node

IHome

node
home




readonly
attribute
Item

IHome

item
home




readonly
attribute
Type

IHome

type
home




readonly
attribute
Property

IHome
}
}
}

#endif




DAIS
DA
SESSION
IDL

property
home




Session

Session
is
an
object
implementing
the
data
access
functions

It
inherits
common
functionality
as
shut
down
callbacks
and
session
status
from
DAIS

Session


group
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Group

IHome
object


node
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Node

IHome
object


item
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Item

IHome
object


type
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Type

IHome
object


property
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Property

IHome
object


















The
DAIS

DataAccess

Node
inherits
most
of
the
functionality
from
DAIS

Node

The
only
difference
is
that
it
supports
to
get
the
tree
root
node




0

*0

*



11
+parent


1
01

n0

n



Node
id


ResourceID
label


string
type


Resourc
eID

from
DAISNode

NodeItemComponent
pathname


string

from
DAISNode




11



0

n0

n



DAIS

DataAccess

Node

IHome
get
root


<<Interface>>
DAIS

Node

Iterator
max
left


next
n


reset


clone


destroy



from
DAISNode

<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids



from
DAISNode

<<Interface>>

Figure
4-6
DAIS
data
access
node
IDL
in
UML











File

DAISDANode
idl#ifndef

DAIS
DANODE
IDL#define

DAIS
DANODE
IDL#pragma
prefix
"omg
org"#include
<DAISNode
idl>
module
DAIS
{module
DataAccess
{module
Node
{
interface
IHome


DAIS

Node

IHome{
ResourceID
get
root




}


}
}
}


#endif




DAIS
DANODE
IDL

IHome

An
object
used
for
browsing
nodes

Most
functionality
is
inherited
from
the
DAIS

Node

IHome
interface


get
root



Get
the
root
node
of
the
whole
tree
of
nodes




Parameter
Description
return
The
root
node
identification


Hierarchical
browsing





Client
Client


DAIS

DataAccess

Node

IHome
DAIS

DataAccess

Node

IHome


DAIS

Node

Iterator
DAIS

Node

Iterator

DAIS

DataAccess

Session
DAIS

DataAccess

Sessionnode
home



get
root



find
by
parent



next
n



find
by
parent



Get
some
nodes
at
the
root
Pick
one
of
the
nodes
at
the
root
and
get
it's
children
next
n



Get
some
nodes
among
the
children
to
the
node
picked
at
the
root
Figure
4-7
Hierarchical
browsing
interaction

Browsing
by
type





Client

Client


DAIS

DataAccess

Session
DAIS

DataAccess

SessioAcess

Node

IHomeAn


DAIS

Datac
DAIS

Dataccess

Node

IHome


DAIS

Node

Iterator

DAIS

Node

Iteratornode
home



find
by
type



next
n



Find
all
nodes
of
a
certain
type
in
sub-tree

in
this
case
the
root
get
root



next
n




Figure
4-8
Browsing
by
type
interaction
















An
item
is
a
property
of
a
node

While
a
node
generally
represents
a
real-world
object

an
item
represents
some
characteristic
of
that
object

for
example

measurement
value

control
variable

or
parameter
related
to
the
measurement
control
process


The
concept
of
an
item
in
DAIS
corresponds
to
the
item
in
OPC

More
precisely

it
corresponds
to
the
“leafs?
in
the
OPC
IOPCBrowseServerAddressSpace
interface

In
the
Resource
Description
Framework

RDF

data
model

the
item
corresponds
to
a
combination
of
a
subject
and
a
predicate

that
is

a
resource
and
a
property


A
node
may
have
many
items

each
representing
a
different
characteristic
of
the
same
real
world
object

An
item
might
represent
a
measured
variable

a
calculated
variable

a
control
variable

or
a
configuration
parameter

An
item
will
typically
have
many
values
where
each
value
corresponds
to
a
time
stamped
sample

a
single
item
value
corresponds
to
a
single
statement
in
the
RDF
model


Each
sample
will
also
have
its
own
quality

An
item
value
is
then
qualified
by
a
time
stamp
and
a
quality


An
item
value
and
its
qualifications
are
represented
by
six
fixed
attributes




•	
value
-
the
value




•	
time
stamp
-
the
time
when
the
value
was
last
updated




•	
quality
-
the
quality
of
the
value




•	
canonical
data
type
-
the
data
type
of
the
value

This
actually
belongs
to
the
property

see
Property

but
it
is
mirrored
at
the
item




•	
access
rights
-
tells
if
the
value
is
read
only

write
only

or
both
read
write

The
access
right
is
common
for
all
item
values
and
belongs
to
the
item




•	
scan
rate
-
the
fastest
rate
with
which
the
value
can
be
expected
to
be
updated

The
scan
rate
is
common
for
all
item
values
and
belongs
to
the
item





For
an
information
model
describing
this
refer
to
Section
4
1
1

“Nodes

Items

Types


and
Properties
?
on
page
4-2
and
Section
4
1
3

“Item
Values
?
on
page
4-4



Each
item
has
a
universal
identity
given
by
its
ItemID

The
ItemID
is
made
up
of
the
ResourceID
of
a
node
and
the
PropertyID
of
a
property

The
ItemID
of
an
item
is
the
same
in
all
views
provided
by
a
DAIS
server

Clients
may
construct
ItemIDs
given
the
identities
of
nodes
and
properties


DAIS
servers
may
be
coordinated
with
DAF
servers
so
that
valid
ItemIDs
can
be
constructed
from
DAF
ResoureIDs


Within
each
view
provided
by
the
server

an
item
has
a
label
that
is
unique
among
all
items
belonging
to
the
same
node

Within
each
view

an
item
has
a
unique
pathname


The
pathname
is
a
string
that
contains
the
item’s
label
and
the
pathname
of
its
node


The
pathname
must
be
a
valid
URI

but
apart
from
that
the
syntax
of
pathnames
is
implementation
dependent


Note
–
In
OPC
the
pathname
is
the
primary
way
to
identify
items
and
is
called
the
ItemID

In
DAIS
the
ResourceID

PropertyID
pair
is
the
primary
identification
and
so
it
is
called
the
ItemID

This
is
a
potential
point
of
confusion

The
two
ItemIDs
play
approximately
the
same
role
in
OPC
and
DAIS
respectively

but
they
are
not
the
same
type


The
item
interfaces
permit
the
stock
of
items
to
be
browsed

Once
an
item
is
located

the
group
interfaces
are
used
to
deliver
its
values

selected
by
source

at
successive
times

In
addition

the
item
interfaces
provide
the
most
current
value
for
the
default
source

In
either
case
the
item
value
and
qualifications
are
represented
by
the
six
fundamental
attributes
listed
above


The
Item
IDL
defines
a
main
interface
Home
for
browsing
among
hierarchically
structured
items

leaf
nodes


The
information
model
describing
the
hierarchical
structure
is
found

in
Section
4
1
1

“Nodes

Items

Types

and
Properties
?
on
page
4-2





DAIS

DataAccess

Item

IHome
<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnam
es


get
ids


get
access
paths


11


11


0

0
n
n



0

0
n
n



Item
cache
value


SimpleV
alue
cache
value
last
updated


DateTim
e
cache
value
quality


DAIS

Quality
scan
rate


unsigned
long
access
rights


DAIS

AccessRights
NodeItem
Component

fro
m
DA
IS
Nod
e

pathname


string



DAIS

DataAccess

Item

Iterator
<<Interface>>
max
left


next
n


reset


clone


destroy



Figure
4-9
DAIS
data
access
item
IDL
in
UML











File

DAISItem
idl
#ifndef

DAIS
ITEM
IDL
#define

DAIS
ITEM
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
DataAccess
{
module
Item
{

struct
Description

{

ItemID
id


string
label


SimpleValue
value



includes
the
canonical
data
type

Quality
dais
quality


DateTime
time
stamp


AccessRights
access
rights


unsigned
long
scan
rate

}

typedef
sequence<
Description
>Descriptions


interface
Iterator
{

boolean
next
n






in

unsigned
long

n





out

Descriptions

items












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownResourceID
{string
reason
}

exception
UnknownItemID
{string
reason
}

exception
InvalidFilter
{string
reason
}

exception
InvalidValueType
{string
reason
}

exception
UnkownTypeID
{string
reason
}

exception
InvalidAccessRight
{string
reason
}


Description
find


in
ItemID
item


raises

UnknownItemID



Descriptions
find
each

in
ItemIDs
items


raises

UnknownItemID



Iterator
find
by
parent


in
ResourceID
node

in
string
filter
criteria

in
SimpleValueType
data
type
filter

in
AccessRights
access
rights
filter



raises

UnknownResourceID




InvalidFilter




InvalidValueType




InvalidAccessRight





Iterator
find
by
type





in
ResourceID

node




in
ResourceIDs

type
filter




in
string

filter
criteria




in
SimpleValueType

data
type
filter




in
AccessRights

access
rights
filter





raises

UnknownResourceID





InvalidFilter





InvalidValueType





UnkownTypeID





InvalidAccessRight






Strings
get
pathnames






in
ItemIDs

items










ItemIDs
get
ids






in
Strings

pathnames










Strings
get
access
paths






in
ItemID

item





raises

UnknownItemID






}
}
}
}





#endif




DAIS
ITEM
IDL




Description




A
struct
describing
an
item







Member

Description



id

The
identification
of
this
item




label

The
label

single
level
designation

of
the
item




value

The
current
value
sample
for
the
item

The
SimpleValue
also
contains
the
data
type




dais
quality

The
current
quality
of
the
value




time
stamp

The
time
stamp
for
the
value
sample




access
rights

States
if
the
value
is
read

write

or
both
read
and
write




scan
rate

States
the
highest
update
rate
that
can
be
expected




Iterator

Refer
to

Section
4
1
5

“Utility
SCADA
EMS
Measurement
Model
?
on
page
4-5

This

interface
corresponds
to
the
OPC
interface
EnumString
with
the
difference
that
the
Iterator
return
the
Description
struct
instead
of
a
single
string


IHome

An
object
used
for
browsing
items
and
corresponds
to
the
IOPCBrowseServerAddressSpace


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


UnknownItemID

An
exception
stating
that
the
resource
or
property
in
the
ItemID
is
unknown


For
methods
taking
a
sequence
of
item
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


InvalidFilter

An
exception
stating
the
filter
criteria
string
is
not
correct

The
likely
reason
behind
this
exception
is
an
erroneously
entered
string


InvalidValueType

An
exception
stating
that
the
SimpleValueType
does
not
exist


UnknownTypeID

An
exception
stating
one
or
more
TypeIDs
does
not
exist


InvalidAccessRight

An
exception
stating
that
the
access
rights
do
not
exist


find



For
a
given
item
browse
position

return
information
about
that
item




Parameter

Description



item

An
item
identification




return

The
item
description




find
each




For
a
sequence
of
items

return
information
about
each
item




Parameter

Description



items

A
sequence
of
item
identifications




return

An
iterator
holding
the
item
descriptions




find
by
parent




For
a
given
node
identification

return
child
items
to
that
node

Hence
to
reach
all
items
using
this
method
repeated
calls
must
be
made
for
each
node
level

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
LEAF




Parameter

Description



node

The
parent
node
identification




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
only
items
with
pathnames
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





data
type
filter

Select
items
having
the
specified
canonical
data
type




access
rights
filter

Select
items
having
the
specified
access
rights




return

An
iterator
holding
item
descriptions
for
items
•
that
are
child
to
the
parent
node

•
matching
the
filter
criteria

data
type
filter

and
access
rights
filter




find
by
type



For
a
sub-tree
given
by
the
node
parameter

return
all
child
items
matching
the
filter
criteria

This
will
return
all
items
under
the
given
sub-tree
root
node

This
will
make
the
items
in
the
sub-tree
to
appear
flattened
out

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
FLAT




Parameter

Description



node

The
identification
for
the
node
defining
the
sub-tree




type
filter

Select
nodes
in
the
sub-tree
having
a
type
matching
any
of
the
types
listed
in
the
type
filter






filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
only
items
with
pathnames
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





data
type
filter

Select
items
having
the
specified
canonical
data
type




access
rights
filter

Select
items
having
the
specified
access
rights




return

An
iterator
holding
item
descriptions
for
items
•
that
are
child
to
nodes
in
the
sub-tree
and
nodes
having
a
type
matching
the
type
filter

•
matching
the
filter
criteria

data
type
filter

and
access
rights
filter




get
pathnames



Translate
a
sequence
of
item
identifications
to
the
corresponding
sequence
of
pathnames

If
an
item
fails
to
translate
to
a
pathname

due
to
an
unknown
identification


the
corresponding
pathname
is
an
empty
string




Parameter

Description



items

The
sequence
of
items




return

The
corresponding
sequence
of
pathnames




get
ids



Translate
a
sequence
of
pathnames
to
the
corresponding
sequence
of
item
identifications

If
a
pathname
fails
to
translate
to
an
item
identification

due
to
an
unrecognized
pathname

the
corresponding
item
identification
is
NULL


get
access
paths



Get
the
possible
communication
paths
how
data
can
be
retrieved
for
the
node

An
access
path
is
expected
to
be
human
readable
so
that
a
human
can
pick
one
and
feed
it
back
to
the
server
as
the
preferred
path

via
other
interfaces





Parameter

Description



item

An
item
identification




return

A
sequence
of
possible
access
paths
for
the
item




Browsing
Items





Client

Client


DAIS

DataAccess

Item

IHome

DAIS

DataAccess

Item

IHome


DAIS

DataAccess

Item

Iterator

DAIS

DataAccess

Item

Iterator

DAIS

DataAccess

Session

DAIS

DataAccess

Sessionnode
home



find
by
parent



next
n



item
home



find
by
parent



Get
the
items
for
a
particular
node
Get
some
item
descriptions
for
the
particular
node
Get
the
items
for
another
node
Get
some
node
of
interest

refer
to
browsing
of
Nodes

Figure
4-10
Browsing
items
interaction
Navigate
across
associations

find
by
parent








Client
Client


DAIS

DataAccess

Item

IHome

DAIS

DataAccess

Item

IHomeataccess

Node

IHomea

DAIS

DA

DAIS

DtaAccess

Node

IHomeGet
information
about
each
item
at
a
known
node
find



Pick
an
item
holding
a
ResourceID
and
get
the
node
information
for
that
ResourceID
find
by
parent



Get
the
item
information
for
the
new
node

Figure
4-11
Navigating
across
associations
interaction

















These
are
definitions
for
transmitting
item
values
to
clients

Interfaces
are
defined
for
server
side
read
and
write
operations
and
client
side
callback
operations

Clients
shall
implement
the
Callback
object
for
the
server
to
use
at
transfer
of
data

A
client
may
have
any
number
of
callback
objects

The
client
shall
connect
each
callback
object
to
a
server
object
implementing
ConnectionPoint


The
IO
interfaces
support
three
different
ways
to
read
data
and
two
different
ways
to
write
data




Read
data



•	
Synchronous
read
where
the
data
is
received
at
return
from
the
sync
read


method




•	
Asynchronous
read
where
the
data
is
returned
at
the
Callback
object




•	
Subscription
where
data
is
sent
spontaneously
by
the
server
at
the
callback
object








Write
data



•	
Synchronous
write
returning
to
the
client
once
all
the
written
data
has
reached
the
devices



•	
Asynchronous
write
returning
when
the
data
is
received
by
the
DAIS
server

A
callback
on
Callback
is
sent
by
the
server
once
the
written
data
has
reached
the
devices




Each
item
value
is
transmitted
in
a
struct
with
a
timestamp
and
quality
indication

A
sequence
of
this
struct
is
either
sent
via
the
callback
object
or
directly
in
read
or
write
calls


In
OPC
the
IO
interface
corresponds
to
the
OPC
interfaces
IOPCSyncIO

IOPCAsyncIO

and
IOPCDataCallback




DAIS

DataAccess

IO

SyncIO
<<Interface>>
sync
read


sync
write


DAIS

DataAccess

IO

ConnectionPoint
<<Interface>>
callback




DAIS

DataAccess

IO

Callback
callback
callback


DAIS

DataAccess

IO

Callback




11


0

0
1
1



DAIS

DataAccess

IO

Callback
<<Interface>>
on
data
change


on
read
complete


on
write
complete


on
cancel
complete


0

*0

*


11



Client

from
DAIS
Server




DAIS

DataAccess

IO

AsyncIO
<<Interface>>
async
read


async
write


refresh


cancel


set
enable


get
enable


DAIS

DataAccess

IO

ItemState
<<struct>>
client
handle


ClientItemHandle
time
stamp


DateTime
dais
quality


DAIS

Quality
value


SimpleValue

Figure
4-12
DAIS
data
access
IO
IDL
in
UML

The
DAISConnectionPoint
callback


methods
correspond
to
a
get
or
set
method
for
the
callback
attribute














File

DAISDAIO
idl#ifndef

DAIS
DAIO
IDL#define

DAIS
DAIO
IDL#pragma
prefix
"omg
org"#include
<DAISCommon
idl>
module
DAIS
{

module
DataAccess
{module
IO
{
enum
DataSource
{


DS
CACHE



DS
DEVICE

}


struct
ItemState

{
SimpleValue
value

DateTime
time
stamp

Quality
dais
quality

ClientItemHandle
client
handle


}
typedef
sequence<ItemState>
ItemStates

struct
ItemUpdate
{
ServerItemHandle
server
handle

SimpleValue
value


}
typedef
sequence<ItemUpdate>
ItemUpdates

interface
SyncIO{
ItemStates
sync
read


in
DataSource
data
source

in
ServerItemHandles
server
handles

out
ItemErrors
errors





ItemErrors
sync
write





in

ItemUpdates
updates










}





typede
f
unsi
gned
long

CancelID




int

erface
AsyncIO



{






exception
NotConnected{string
reason
}

exception
InvalidCancelID{string
reason
}

exception
NotActive{string
reason
}


CancelID
async
read


in
ServerItemHandles
server
handles

in
DataSource
data
source

in
unsigned
long
transaction
id



raises

NotConnected

NotActive



CancelID
async
write


in
ItemUpdates
updates


in
unsigned
long
transaction
id


raises

NotConnected



CancelID
refresh



in
DataSource
data
source



raises

NotConnected
NotActive



void
cancel


in
CancelID
cancel
id
in
unsigned
long
transaction
id



raises

InvalidCancelID



attribute
boolean
enabled

}


interface
Callback
{

void
on
data
change


in
unsigned
long
transaction
id

in
boolean
all
quality
good

in
ItemStates
states





void
on
read
complete


in
unsigned
long
transaction
id

in
boolean
all
quality
good

in
ItemStates
states

in
ItemErrors
errors





void
on
write
complete


in
unsigned
long
transaction
id

in
ItemErrors
errors





void
on
cancel
complete







in

unsigned
long

transaction
id













}








interface
ConnectionPoint
{

attribute
Callback
cllbck

}
}
}
}

#endif




DAIS
DAIO
IDL
DataSource



Member

Description



DS
CACHE

Data
cached
in
the
server
is
requested




DS
DEVICE

Data
from
the
device
is
requested

This
will
force
a
read
from
the
device
or
RTU

A
read
from
device
will
be
made
regardless
of
the
group
or
item
active
status
and
no
group
NotActive
exception
will
be
forced




ItemState

The
struct
is
the
major
carrier
of
data
conveyed
over
the
interface

It
is
the
“message?
holding
the
payload




Member

Description



value

The
value
itself




time
stamp

The
time
stamp
when
the
value
was
last
updated




quality

The
quality
for
the
value




client
handle

A
client
side
handle
enabling
the
client
to
make
a
quick
look
up
of
the
item
in
its
internal
data
structures




ItemUpdate

The
struct
carry
an
update
for
an
item




Member

Description



server
handle

A
server
side
handle
enabling
the
server
to
make
a
quick
look
up
of
the
item
in
its
internal
data
structures




value

The
value
that
shall
be
used
in
the
update




SyncIO

An
interface
for
the
synchronous
operations


sync
read



Synchronous
read
of
items

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




Parameter

Description



data
source

The
source
from
where
to
read
the
data




server
handles

A
sequence
specifying
the
whole
or
a
subset
of
the
server
side
handles
as
defined
via
the
DAIS

GroupEntry

Manager
interface




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
INVALID
DAIS
HANDLE



return

A
sequence
of
ItemStates
for
the
items




sync
write



Synchronous
write
of
item
values
to
devices

not
the
internal
server
cache


The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
all
or
a
subset
of
the
items
defined
for
a
GroupEntry

Manager

The
ItemUpdate

value
member
is
used
to
update
the
items
in
devices




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
INVALID
DAIS
HANDLE
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



AsyncIO

An
interface
for
asynchronous
read
or
write
operations


NotConnected

An
exception
telling
that
there
is
no
callback
object
connected
by
the
client


InvalidCancelID

An
exception
telling
that
the
supplied
cancel
id
number
is
not
recognized


NotActive

An
exception
telling
that
the
group
or
all
items
in
the
group
is
inactive

Only
issued
when
read
from
cache


async
read



Asynchronous
read
of
items
from
devices

OPC
may
report
read
errors
both
at
return
from
async
read


and
at
on
read
complete



DAIS
will
report
all
errors
at
on
read
complete







Parameter

Description



server
handles

A
sequence
specifying
the
whole
or
a
subset
of
the
server
side
handles

as
defined
via
the
DAIS

GroupEntry

Manager
interface




data
source

The
source
from
where
to
read
the
data

When
reading
from
cache

inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
read
operation




async
write



Asynchronous
write
of
item
values
to
devices

not
the
internal
server
cache


OPC
may
report
write
errors
both
at
return
from
async
write


and
at
on
write
complete



DAIS
will
report
all
errors
at
on
write
complete






Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
all
or
a
subset
of
the
items
defined
for
a
DAIS

GroupEntry

Manager

The
ItemUpdate

value
member
is
used
to
update
the
items
in
devices




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
write
operation




refresh



Initiate
a
complete
asynchronous
read
transfer
for
all
item
entries
defined
via
the

DAIS

DataAccess

GroupEntry

Manager
interface

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE


The
cyclic
on
data
change
reporting
continues
unaffected
by
a
refresh
call

However

items
still
unchanged
after
a
refresh
will
not
be
reported
in
a
succeeding
on
data
change
call




Parameter

Description



data
source

The
source
from
where
to
read
the
data




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
data
change
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
refresh
operation




cancel



Cancel
on
ongoing
refresh

async
read

or
async
write
operations

The
server
is
expected
to
acknowledge
a
successfully
initiated
cancel
operation
with
an
on
cancel
complete


callback




Parameter

Description



cancel
id

The
server
generated
cancellation
number
for
the
operation




to
cancel




enable

An
attribute
used
to
enable
or
disable
the
spontaneous
on
data
change


callbacks

The
enable
state
does
not
affect
on
data
change
response
to
refresh
calls

When
a
group
is
created
it
is
enabled
by
default


Callback

An
interface
implemented
by
the
client
and
used
by
the
server
to
send
data
to
the
client


on
data
change



The
method
is
called
by
the
server
when
spontaneous
changes
occur
or
when
the
client
has
requested
an
explicit
refresh

Only
active
items
are
reported
in
spontaneous
calls




Parameter

Description



transaction
id

If
the
call
is
in
response
to
a
refresh

the
transaction
number
for
that
refresh
call

If
the
call
is
autonomous
due
to
one
or
more
spontaneous
changes

the
number
is
zero




all
quality
good

All
item
quality
values
are
good




item
states

A
sequence
of
requested
or
spontaneously
changed
ItemStates




on
read
complete



The
method
is
used
by
the
server
to
report
data
in
response
to
an
asynchronous
read




Parameter

Description



transaction
id

The
transaction
number
for
the
corresponding
read




all
quality
good

All
item
quality
values
are
good

This
requires
that
no
errors
are
reported
in
the
error
parameter
below




item
states

A
sequence
of
ItemStates
matching
the
read
operation




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
initially
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
ERROR
INVALID
DAIS
HANDLE



on
write
complete



The
method
is
used
to
report
the
success
of
an
asynchronous
write
operation




Parameter

Description



transaction
id

The
transaction
number
for
the
corresponding
write




errors

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
all
write
operations
initially
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
INVALID
DAIS
HANDLE
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



on
cancel
complete



The
method
is
used
to
acknowledge
the
completion
of
a
successfully
initiated
cancel
call




Parameter
Description
transaction
id
The
transaction
number
for
the
corresponding
cancel


ConnectionPoint

An
interface
used
by
the
client
to
connect
or
disconnect
a
client
callback
object
at
the
server


callback

An
attribute
referencing
the
callback
object


In
an
implementation
one
get
and
one
set
method
will
implement
the
callback
attribute

Due
to
limitation
in
the
UML
tool
used
to
draw
the
diagrams

the
attribute
is
represented
by
the
two
methods
connect
and
disconnect
















A
group
has
a
collection
of
group
entries

Each
group
entry
associates
the
group
with
an
item

An
ItemID
identifies
a
group
entry
within
its
group

The
pathname
of
an
item
may
be
used
as
an
alternative
to
the
ItemID
when
the
group
entry
is
created

see

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15




In
OPC
the
GroupEntry
interface
corresponds
to
the
interface
IOPCItemMgt







DAIS

DataAccess

GroupEntry

Manager
<<Interface>>
create
entries


validate
entries


remove
entries


set
active
state


set
inactive
state


set
client
handles


set
data
types


create
group
entry
iterator





11



0

0
n
n


11


0

0
*
*



GroupEntry
pathname


string
item


DAIS

ItemID
active


boolean
access
path


string
client
handle


ClientItemHandle
requested
data
type


SimpleValueType
access
rights


AccessRights
canonical
data
type


SimpleValueType



DAIS

DataAccess

GroupEntry

Iterator
<<Interface>>
max
left


next
n


reset


clone


destroy



Figure
4-13
DAIS
data
access
group
entry
IDL
in
UML











File

DAISGroupEntry
idl
#ifndef

DAIS
GROUP
ENTRY
IDL
#define

DAIS
GROUP
ENTRY
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
DataAccess
{
module
GroupEntry
{

struct
Description



{



ServerItemIdentification

server
item
id




string

access
path




ClientItemHandle

client
handle




SimpleValueType

requested
data
type




boolean

active




}





typedef
sequence<Description
>

Descriptions




struct
DetailedDescription




{






ItemID

item





string

pathname





string

access
path





ServerItemHandle

server
handle




ClientItemHandle
client
handle
SimpleValueType
requested
data
type
SimpleValueType
canonical
data
type
AccessRights
access
rights
boolean
active

}
typedef
sequence<DetailedDescription>
DetailedDescriptions

struct
Result
{
ServerItemHandle
server
handle

ClientItemHandle
client
handle

AccessRights
access
rights

SimpleValueType
canonical
data
type


}
typedef
sequence<Result>
Results

struct
HandleAssociation
{
ServerItemHandle
server
handle

ClientItemHandle
client
handle


}

typedef
sequence<HandleAssociation>HandleAssociations


struct
DataTypeDescription

{
ServerItemHandle
server
handle

SimpleValueType
requested
data
type


}

typedef
sequence<DataTypeDescription>DataTypeDescriptions


interface
Iterator
{

boolean
next
n

in
unsigned
long
n
out
DetailedDescriptions
entries



void
reset



Iterator
clone



void
destroy




}


interface
Manager
{

Results
create
entries

in
Descriptions
entries
out
ItemErrors
errors




Results
validate
entries





in

Descriptions

entries




out

ItemErrors

errors










ItemErrors
remove
entries






in

ServerItemHandles

server
handles










ItemErrors
set
active
state






in

ServerItemHandles

server
handles










ItemErrors
set
inactive
state






in

ServerItemHandles

server
handles










ItemErrors
set
client
handles






in

HandleAssociations

handle
associations










ItemErrors
set
data
types






in

DataTypeDescriptions

descriptions










Iterator
create
group
entry
iterator



}
}
}
}
#endif




DAIS
GROUP
ENTRY
IDL

Description
The
struct
describes
a
group
entry
for
an
item

The
client
to
configure
new
entries
in
a
group
uses
it

It
directly
corresponds
to
the
OPCItemDef
struct




Member

Description



server
item
id

The
identification
of
the
item




access
path

The
access
path
used
by
the
server
to
connect
to
the
device
and
sensor

An
empty
string
as
input
tells
the
server
to
select
the
access
path




client
handle

The
client
provided
handle
to
the
item




requested
data
type

The
data
type
requested
by
the
client
for
the
value




active

Tells
if
the
item
is
active
and
data
from
devices
is
updated
in
the
cache




DetailedDescription

The
struct
is
used
to
deliver
group
entry
information
to
the
client

In
OPC
this
is
made
with
the
struct
OPCITEMATTRIBUTES

Description
is
used
for
both
these
OPC
structs




Member

Description



item

The
item
identification
by
an
ItemID




pathname

A
string
concatenating
the
labels
for
all
nodes
in
the
path
from
the
item
up
to
the
root




access
path

The
access
path
used
by
the
server
to
connect
to
the
device
and
sensor

An
empty
string
as
input
tells
the
server
to
select
the
access
path




server
handle

Server
provided
handle
for
the
item




client
handle

Client
provided
handle
for
the
item




requested
data
type

The
data
type
requested
by
the
client
for
the
value




canonical
data
type

The
data
type
the
server
uses
internally
for
the
value




access
rights

The
access
rights

read

write

and
read-write




active

Tells
if
the
item
is
active
and
data
from
devices
is
updated
in
the
cache




Result

The
struct
is
used
to
transfer
the
result
from
a
create
entries


or
validate
entries


call
back
to
a
client

In
OPC
the
corresponding
struct
is
OPCITEMRESULT




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




client
handle

The
supplied
client
handle
for
the
item




access
rights

The
access
rights

read

write

and
read-write




canonical
data
type

The
data
type
the
server
uses
internally
for
the
value




HandleAssociation

The
struct
is
used
to
change
the
association
between
server
handles
and
client
handles
in
the
set
client
handle


method




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




client
handle

The
new
client
handle
wanted
by
the
client




DataTypeDescription

The
struct
is
used
to
change
the
data
type
of
the
value
delivered
in
the
ItemState
struct




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




requested
data
type

The
new
data
type
wanted
by
the
client




Iterator

Refer
to

Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10

The
interface
directly

corresponds
to
the
EnumOPCItemAttributes
interface


Manager

An
interface
for
creation
and
browsing
of
group
entries

The
interface
directly
corresponds
to
the
IOPCItemMgt
interface


create
entries



Adds
one
or
more
entries
to
a
group




Parameter

Description



entries

Group
entry
descriptions
for
entries
to
be
created




errors

A
sequence
of
structs
reporting
the
items
that
were
not
entered
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
UNKNOWN
PATHNAME
•
ERROR
BAD
TYPE
•
ERROR
UNKNOWN
ACCESS
PATH



return

A
sequence
of
result
descriptions
for
the
entries
that
were
entered
in
the
group




validate
entries



Is
used
to
determine
if
an
item
is
valid

could
it
be
added
without
error


Also
returns
information
about
the
item
such
as
canonical
datatype

Does
not
affect
the
group
in
any
way




Parameter

Description



entries

Group
entry
descriptions
for
entries
to
be
validated




errors

A
sequence
of
structs
reporting
the
items
that
could
not
be
validated
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
UNKNOWN
PATHNAME
•
ERROR
BAD
TYPE
•
ERROR
UNKNOWN
ACCESS
PATH



return

A
sequence
of
result
descriptions
for
the
entries
that
were
validated




remove
entries



Used
to
remove
entries
from
a
group




Parameter

Description



server
handles

Server
handles
for
entries
that
shall
be
removed




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
removed
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
active
state



Used
to
activate
individual
items
in
a
group

Activate
state
means
that
the
server
acquires
data
from
devices

Inactive
state
means
that
the
server
does
not
acquire
any
data

The
group
enable
state
control
if
acquired
data
shall
be
sent
further
to
subscribers
via
on
data
change




Parameter

Description



server
handles

Server
handles
for
items
to
activate




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
activated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
inactive
state



Used
to
deactivate
individual
items
in
a
group




Parameter

Description



server
handles

Server
handles
for
items
to
deactivate




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
deactivated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
client
handles



Used
to
change
the
client
handles
for
items




Parameter

Description



handle
associations

Change
descriptions
for
the
items
where
to
change
the
client
handles




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
updated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
data
types



Used
to
change
the
requested
data
types
for
items




Parameter

Description



descriptions

Change
descriptions
for
the
items
where
to
change
the
data
types




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
updated
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
BAD
TYPE



create
group
entry
iterator



Used
to
create
a
group
entry
iterator

Used
by
clients
to
inspect
existing
group
entries




Parameter
Description
return
The
GroupEntry
Iterator


















A
group
is
a
collection
of
items
and
a
connection
to
one
or
more
consumers
of
item
values

Clients
create
groups
and
their
lifetime
is
bounded
by
the
session
to
which
they
belong


See

Section
4
2
2

“DAISDASession
IDL
?
on
page
4-8




The
purpose
of
a
group
is
to
convey
selected
item
values
to
a
client

A
callback
object

may
be
connected
to
a
group
to
receive
item
value
information

see
Section
4
2
5


“DAISDAIO
IDL
?
on
page
4-23


Items
may
be
added
and
removed
from
a
group
as

group
entries

see

Section
4
2
6

“DAISGroupEntry
IDL
?
on
page
4-32


A
group
has
an

update
rate
that
determines
how
frequently
updated
values
for
its
entries
are
notified
to
its
connected
callback
objects

A
group
also
has
other
states
that
control
its
notification
behavior


A
group
may
also
be
initialized
with
a
predefined
set
of
entries

A
set
of
entries
is
called
a
public
group
and
is
identified
by
a
ResourceID

A
client
can
create
or
remove
public
groups

A
server
may
represent
a
public
group
as
a
node
such
that
the
ResourceID
of
the
public
group
and
the
node
are
identical

This
would
allow
clients
to
locate
public
groups
by
name


The
DAIS


DataAccess

Group

Manager
object
implements
interfaces
from
the
DAISDAIO
and
DAISGroupEntry
IDLs

This
is
specified
by
inheritance
of
interfaces
as
seen
in

Figure
4-14


A
DAIS

DataAccess

Group

Manager
has
a
state
given
by
the
DAIS

DataAccess

Group

State
struct
and
a
DAIS

DataAccess

Group

Manager
object
is
created
from
the
DAIS

DataAccess

Group

IHome
object


In
OPC
the
Group
interface
corresponds
to
the
interfaces
IOPCGroupStateMgt
and
IOPCPublicGroupStateMgt




DAIS

DataAccess

IO

ConnectionPoint

from
DAISDAIO

<<Interface>>
callback




DAIS

DataAccess

IO

Callback
callback
callback


DAIS

DataAccess

IO

Callback




11



0

10

1



DAIS

DataAccess

IO

Callback

from
DAISDAIO

<<Interface>>



DAIS

DataAccess

IO

SyncIO

from
DAISDAIO

<<Interface>>
sync
read


sync
write


DAIS

DataAccess

IO

AsyncIO

fromDAISDAIO

<<Interface>>
async
read


async
write


refresh


cancel


set
enable


get
enable


DAIS

DataAccess

GroupEntry

Manager

from
DAISGrou
pEntry

<<Interface>>
create
entries


validate
entries


remove
entries


set
active
state


set
inactive
state


set
client
handles


set
data
types


create
group
entry
iterator





DAIS

DataAccess

GroupEntry

Iterator

from
DAISGroupEntry

<<Interface>>



0

*0

*


11



DAIS

DataAccess

Group

Manager
<<Interface>>
get
state


set
state


clone


clone
group
to
public


destroy





0

n0

n



11



DAIS

DataAccess

Group

IHome
<<Interface>>
find
public
groups


find


create
group


clone
group
from
public


remove
public
group





11



11



DAIS

DataAccess

Group

State
update
rate


unsigned
long
active


boolean
time
bias


long
percent
dead
band


double
locale
id


unsigned
long
name


string

Figure
4-14
DAIS
data
access
group
IDL
in
UML











File

DAISGroup
idl
#ifndef

DAIS
GROUP
IDL
#define

DAIS
GROUP
IDL
#pragma
prefix
"omg
org"

#include
<DAISCommon
idl>
#include
<DAISGroupEntry
idl>
#include
<DAISDAIO
idl>

module
DAIS
{
module
DataAccess
{
module
Group
{

exception
DuplicateName
{string
reason
}


struct
State
{




string

name





unsigned
long

update
rate





boolean

active





long

time
bias





double

percent
deadband





unsigned
long

locale
id




}






struct
PublicGroupDescription

{
ResourceID
id

State
group
state


}

typedef
sequence<PublicGroupDescription>PublicGroupDescriptions


interface
Manager


GroupEntry

Manager

IO

AsyncIO

IO

SyncIO

IO

ConnectionPoint

{

State
get
state





unsigned
long
set
state


in
State
group
state


raises

DuplicateName



Manager
clone


in
string
name


raises

DuplicateName



PublicGroupDescription
clone
group
to
public


in
string
name


raises

DuplicateName



void
destroy




}

interface
IHome
{

exception
UnknownResourceID
{string
reason
}


PublicGroupDescriptions
find
public
groups




PublicGroupDescription
find

in
ResourceID
public
group


raises

UnknownResourceID


Manager
create
group



in
State
group
state


out
unsigned
long
revised
update
rate



raises

DuplicateName



Manager
clone
group
from
public



in
ResourceID
public
group


in
string
name



raises

DuplicateName

UnknownResourceID



void
remove
public
group



in
ResourceID
public
group



raises

UnknownResourceID


}
}
}
}

#endif




DAIS
GROUP
IDL

DuplicateName

An
exception
raised
when
an
object
is
created
and
the
name
already
exists

No
object
is
created
if
the
exception
is
raised

Used
for
session
and
group
manager
objects


State

The
struct
contains
information
about
the
group
state




Members

Description



name

Within
the
session
and
public
groups

unique
name
of
the
group




update
rate

Update
rate
for
the
group
in
milliseconds

When
used
as
input
it
specifies
the
fastest
rate
at
which
data
changes
may
be
sent
to
on
data
change


for
items
in
this
group

This
also
indicates
the
desired
accuracy
of
cached
data

This
is
intended
only
to
control
the
behavior
at
the
interface

How
the
server
deals
with
the
update
rate
and
how
often
it
actually
polls
the
hardware
internally
is
an
implementation
detail

Passing
0
indicates
the
server
should
use
the
fastest
practical
rate






active

Indicates
if
the
group
is
active
and
data
from
devices
is
updated
in
the
cache




time
bias

The
time
bias
in
minutes
for
the
group

A
zero
value
when
used
as
input
will
tell
the
server
to
use
the
default
system
time
bias

This
bias
behaves
like
the
Bias
field
in
the
Win32
TIME
ZONE
INFORMATION
structure




percent
deadband

The
percent
change
for
an
item
value
that
will
cause
a
call
back
for
that
value

This
parameter
only
applies
to
items
in
the
group
that
are
of
analog
type

If
a
client
specifies
a
zero
deadband

the
value
will
be
reported
with
the
update
rate




locale
id

The
localization
number
for
the
language
used
when
returning
string
values




Manager

An
object
used
to
manage
a
group

It
has
a
set
of
methods
related
to
the
group
itself

It
also
inherits
methods
from
interfaces
for
group
entry
management
and
data
transfer

For

group
entry
management
refer
to
Section
4
2
6

“DAISGroupEntry
IDL
?
on
page
4-32

and
for
data
transfer
refer
to

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15

The

DAIS

DataAccess

Group

Manager
interface
corresponds
to
the
IOPCGroupStateMgt
interface


get
state



The
method
gets
the
group
status




Parameter
Description
return
State

set
state



The
method
sets
the
group
status




Parameter

Description



group
state

The
State
with
the
updates

All
members
will
be
updated

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
update
is
made




return

The
closest
update
rate
the
server
is
able
to
provide
for
the
group




clone



Create
a
copy
of
a
group




Parameter

Description



name

The
name
to
be
given
for
the
new
group

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
clone
is
created




return

A
description
of
the
public
group




clone
group
to
public




Create
a
public
copy
of
a
group
including
all
items
and
the
group
state




Parameter

Description



name

The
name
to
be
given
for
the
new
group

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
public
group
is
created




return

A
description
of
the
public
group




destroy



Delete
the
group


PublicGroupDescription

A
struct
describing
public
groups




Member

Description



id

A
ResourceID
identifying
the
public
group




group
state

The
group
state
struct
including
the
group
name




IHome

The
factory
object
for
groups

The
corresponding
OPC
interface
is
IOPCServer


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

For
methods
taking
a
sequence
of
resource
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find
public
groups



Find
all
public
groups
defined
in
the
server




Member
Description
return
A
sequence
of
public
group
descriptions


find



For
a
given
public
group

return
information
about
that
group




Member

Description



public
group

A
ResourceID
identifying
the
public
group




return

A
public
group
description




create
group



Create
a
new
initially
empty
group




Parameter

Description



group
state

The
State
to
be
set
for
the
new
group




revised
update
rate

The
closest
update
rate
the
server
is
able
to
provide
for
the
group




return

The
new
group




clone
group
from
public



Create
a
copy
from
a
public
group
having
an
existing
set
of
entries
and
state




Parameter

Description



public
group

The
identification
of
the
public
group




name

The
name
of
the
new
group




return

The
new
group




remove
public
group



Remove
a
public
group




Parameter

Description



public
group

The
identification
of
the
public
group




return

None



Group
management





Client
Client


DAIS

DataAccess

Session

DAIS

DataAcce
Grup

IHome
Gss

Session


DAIS

DataAccess
o

DAIS

DataAccess
roup

IHome


DAIS

DataAccess

Group

Manager

DAIS

DataAccess

Group

Managergroup
home



create
group



create
entries



Do
work
with
group
manager

e
g

activate
subscription
destroy




Figure
4-15
Group
management
interaction

Activate
subscription





Client

Client


DAIS

DataAccess

Group

Manager
DAIS

DataAccess

Group

Managerss
IO

Callbacks

DAIS

DataAcce

DAIS

DataAcces

IO

Callbackcallback
DAISDACallback

refresh



on
data
change



Forced
by
refresh
on
data
change



Spontaneous
on
data
change



Spontaneous

Figure
4-16
Active
subscription
interaction
Activate
a
subscription
silently





Client

Client


DAIS

DataAccess

Group

Manager

DAIS

DataAccess

Group

Managerss
IO

Callbacks

DAIS

DataAcce


DAIS

DataAcces

IO

Callbackset
inactive
state



callback



set
enable



set
active
state



Disable
refresh



on
data
change



set
enable



Enable
on
data
change




Figure
4-17
Activate
a
subscription
silently
interaction
Cancel





DAIS

DataAccess

Group

M
anager
DAIS

DataAccess

Group

Manager


DAIS

DataAccess

IO

Callback

DAIS

DataAccess

IO

CallbackCancel
refresh
operation
Cancel
async
read
Cancel
async
write


Client

Clienton
cancel
complete



on
cancel
complete



on
cancel
complete




refresh




cancel




async
read




cancel




async
write




cancel




Figure
4-18
Cancellation
interaction

















The
purpose
of
the
interface
is
to
provide
a
simple
read
and
write
of
data

The
functionality
is
the
same
as
the
synchronous
read
and
write
described
in

Section
4
2
5


“DAISDAIO
IDL
?
on
page
4-23

but
without
having
to
create
a
group












File

DAISDASimpleIO
idl#ifndef

DAIS
DA
SIMPLE
IO
IDL#define

DAIS
DA
SIMPLE
IO
IDL#include
<DAISCommon
idl>
module
DAIS
{module
DataAccess
{module
SimpleIO
{
enum
DataSource
{


DS
CACHE



DS
DEVICE

}


struct
ItemError
{



}

typ
Error
ServerItemIdentification
string
edef
sequence<ItemError>

err

id

reason

ItemErrors




{
str
uct
ItemState





SimpleValue
DateTime
Quality
ServerItemIdentification

value

time
stamp

dais
quality

id




}






typedef
sequence<ItemState>ItemStates


struct
ItemUpdate

{
ServerItemIdentification
id

SimpleValue
value


}
typedef
sequence<ItemUpdate>
ItemUpdates

interface
IHome
{
ItemStates
read


in
DataSource
data
source

in
ServerItemIdentifications
ids

out
ItemErrors
errors





ItemErrors
write
with
qt


in
ItemStates
updates




ItemErrors
write


in
ItemUpdates
updates




}
}
}
}

#endif




DAIS
DA
SIMPLE
IO
IDL
DataSource

Find
all
public
groups
defined
in
the
server




Member

Description



DS
CACHE

Data
cached
in
the
server
is
requested




DS
DEVICE

Data
from
the
device
is
requested

This
will
force
a
read
from
the
device
or
RTU

A
read
from
device
will
be
made
regardless
of
the
group
or
item
active
status
and
no
group
NotActive
exception
will
be
forced




ItemError

A
struct
for
reporting
of
item
related
errors

The
struct
is
different
from
the
DAIS

ItemError
because
no
handles
are
used
to
identify
the
item
in
SimpleIO




Member

Description



err

An
error
code
as
described
for
DAIS

ItemError




id

The
identification
of
the
item




reason

An
additional
text
explaining
the
error




ItemState

The
struct
is
the
carrier
of
data
conveyed
over
the
interface

It
is
the
“message?
holding
the
payload

This
is
basically
the
same
struct
as
DataAccess

IO

ItemState
with
the
difference
that
instead
of
a
handle
for
identification
the
full
server
identification
is
used




Member

Description



value

The
value
itself




time
stamp

The
time
stamp
when
the
value
was
last
updated




quality

The
quality
for
the
value




id

The
identification
of
the
value
in
the
server




ItemUpdate

The
struct
carries
an
update
for
an
item




Member

Description



id

The
identification
of
the
value
in
the
server




value

The
value
that
shall
be
used
in
the
update




IHome

The
interface
for
simple
IO
operations


read

Synchronous
read
of
items

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




Parameter

Description



data
source

The
source
from
where
to
read
the
data

see
DataSource
above




ids

A
sequence
specifying
the
server
identifications
to
read




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID



return

A
sequence
of
ItemStates
for
the
items




write
with
qt

Synchronous
write
of
item
values
including
quality
and
time
stamp

The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemStates
specifying
the
updates
including
time
stamp
and
quality




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



write

Synchronous
write
of
item
values
only

The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
the
update
values




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE











The
IDL
is
divided
into
files

Each
file
is
modeled
as
a
package
in
UML

A
file
that

depends
on
declarations
made
in
another
file
needs
to
include
it

Figure
4-4
shows
how

the
IDL
files
depend
on
each
other




DAISCommon

from
Common

DAISDAIO
DAISGroupEntry

DAISItem
DAISNode

from
Common

DAISProperty
DAISType

from
Common


from
Common


DAISGroup
DAISDASimpleIO



DAISDASession
DAISDANode
DAISSession

from
Common

DAISServer


from
Server


Figure
4-4
Dependencies
between
data
access
IDL
files













The
DAIS

DataAccess

Session
object
implements
the
data
access
service
on
a
per
client
basis

A
data
access
session
object
has
a
number
of
services
provided
by
one
singleton
home
object
each

Each
home
object
provides
methods
for
manipulation
of
the
data
of
the
specific
type
they
provide

Rather
than
exposing
data
as
objects
with
interfaces
it
is
exposed
as
structs
or
sequences
of
structs

The
reason
is
that
a
large
number
of
data
items
will
become
a
performance
bottleneck
if
instantiated
as
objects
over
an
interface

The
DAIS

Group

IHome
object
is
the
only
object
to
expose
its
data
as
objects

that
is

the
DAIS

Group

Manager

Each
DAIS

Group

Manager
is
expected
to
connect
to
one
callback
object
implemented
by
the
client


Each
client
may
instantiate
one
or
more
Sessions

The
Session
objects
have
one
Type
and
Property
Home
object
each

The
client
shall
expect
that
all
Type
and
Property
Home
objects
expose
the
same
types
and
properties


The
session
object
corresponds
to
an
OPCServer
object


1
0

1
10

1



DAIS

Session

from
DAISSess
ion

<<Interface>>
status




DAIS

SessionStatus
callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy


DAIS

DataAccess

Session
<<Interface>>
group
home




DAIS

DataAccess

Group

IHome
simple
io
home


DAIS

DataAccess

SimpleIO

IHome


node
home




DAIS

DataAccess

Node

IHome
item
home




DAIS

DataAccess

Item

IHome
type
home




DAIS

Type

IHome
property
home




DAIS

Property

IHome



DAIS

ShutdownCallback

from
DAISSessi
on

<<Interface>>



0

10

1



11



Client

fro
m
DAISServer




11



0

*0

*



11



DAIS

Type

IHome

f
rom
DAIST
ype

<<Interface>>



DAIS

DataAccess

IO

Callback

from
DAISDAIO

<<Interface>>






DAIS

Property

IHome

from
DAISProperty

<<Interface>>



0

10

1



11



11



11



DAIS

DataAccess

Node

IHome

from
DAISDANode


<<Interface>>



DAIS

DataAccess

IO

ConnectionPoint

from
DAISDAIO

<<Interface>>



11



DAIS

DataAccess

Group

IHome

from
DAISGroup

<<Interface>>
DAIS

DataAccess

Item

IHome

from
DAI
SItem

<<Interface>>






11

1
0



n

10




DAIS

DataAccess

Group

Manager

from
DAISGroup

<<Interface>>



11



DAIS

DataAccess

SimpleIO

IHome

from
DAISDASi
mp
leIO

<<Interface>>




Figure
4-5
DAIS
data
access
session
IDL
in
UML










File

DAISDASession
idl
#ifndef

DAIS
DA
SESSION
IDL
#define

DAIS
DA
SESSION
IDL
#pragma
prefix
"omg
org"






Common
Information
#include
<DAISNode
idl>
#include
<DAISProperty
idl>
#include
<DAISSession
idl>






Data
Access
interface
#include
<DAISType
idl>
#include
<DAISItem
idl>
#include
<DAISDANode
idl>
#include
<DAISGroup
idl>
#include
<DAISDASimpleIO
idl>



module
DAIS
{
module
DataAccess
{



interface
Session


DAIS

Session
{



readonly
attribute
Group

IHome

group
home




readonly
attribute
SimpleIO

IHome

simple
io
home




readonly
attribute
Node

IHome

node
home




readonly
attribute
Item

IHome

item
home




readonly
attribute
Type

IHome

type
home




readonly
attribute
Property

IHome
}
}
}

#endif




DAIS
DA
SESSION
IDL

property
home




Session

Session
is
an
object
implementing
the
data
access
functions

It
inherits
common
functionality
as
shut
down
callbacks
and
session
status
from
DAIS

Session


group
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Group

IHome
object


node
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Node

IHome
object


item
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Item

IHome
object


type
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Type

IHome
object


property
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Property

IHome
object
















The
DAIS

DataAccess

Node
inherits
most
of
the
functionality
from
DAIS

Node

The
only
difference
is
that
it
supports
to
get
the
tree
root
node




0

*0

*



11
+parent


1
01

n0

n



Node
id


ResourceID
label


string
type


Resourc
eID

from
DAISNode

NodeItemComponent
pathname


string

from
DAISNode




11



0

n0

n



DAIS

DataAccess

Node

IHome
get
root


<<Interface>>
DAIS

Node

Iterator
max
left


next
n


reset


clone


destroy



from
DAISNode

<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids



from
DAISNode

<<Interface>>

Figure
4-6
DAIS
data
access
node
IDL
in
UML










File

DAISDANode
idl#ifndef

DAIS
DANODE
IDL#define

DAIS
DANODE
IDL#pragma
prefix
"omg
org"#include
<DAISNode
idl>
module
DAIS
{module
DataAccess
{module
Node
{
interface
IHome


DAIS

Node

IHome{
ResourceID
get
root




}


}
}
}


#endif




DAIS
DANODE
IDL

IHome

An
object
used
for
browsing
nodes

Most
functionality
is
inherited
from
the
DAIS

Node

IHome
interface


get
root



Get
the
root
node
of
the
whole
tree
of
nodes




Parameter
Description
return
The
root
node
identification


Hierarchical
browsing





Client
Client


DAIS

DataAccess

Node

IHome
DAIS

DataAccess

Node

IHome


DAIS

Node

Iterator
DAIS

Node

Iterator

DAIS

DataAccess

Session
DAIS

DataAccess

Sessionnode
home



get
root



find
by
parent



next
n



find
by
parent



Get
some
nodes
at
the
root
Pick
one
of
the
nodes
at
the
root
and
get
it's
children
next
n



Get
some
nodes
among
the
children
to
the
node
picked
at
the
root
Figure
4-7
Hierarchical
browsing
interaction

Browsing
by
type





Client

Client


DAIS

DataAccess

Session
DAIS

DataAccess

SessioAcess

Node

IHomeAn


DAIS

Datac
DAIS

Dataccess

Node

IHome


DAIS

Node

Iterator

DAIS

Node

Iteratornode
home



find
by
type



next
n



Find
all
nodes
of
a
certain
type
in
sub-tree

in
this
case
the
root
get
root



next
n




Figure
4-8
Browsing
by
type
interaction














An
item
is
a
property
of
a
node

While
a
node
generally
represents
a
real-world
object

an
item
represents
some
characteristic
of
that
object

for
example

measurement
value

control
variable

or
parameter
related
to
the
measurement
control
process


The
concept
of
an
item
in
DAIS
corresponds
to
the
item
in
OPC

More
precisely

it
corresponds
to
the
“leafs?
in
the
OPC
IOPCBrowseServerAddressSpace
interface

In
the
Resource
Description
Framework

RDF

data
model

the
item
corresponds
to
a
combination
of
a
subject
and
a
predicate

that
is

a
resource
and
a
property


A
node
may
have
many
items

each
representing
a
different
characteristic
of
the
same
real
world
object

An
item
might
represent
a
measured
variable

a
calculated
variable

a
control
variable

or
a
configuration
parameter

An
item
will
typically
have
many
values
where
each
value
corresponds
to
a
time
stamped
sample

a
single
item
value
corresponds
to
a
single
statement
in
the
RDF
model


Each
sample
will
also
have
its
own
quality

An
item
value
is
then
qualified
by
a
time
stamp
and
a
quality


An
item
value
and
its
qualifications
are
represented
by
six
fixed
attributes




•	
value
-
the
value




•	
time
stamp
-
the
time
when
the
value
was
last
updated




•	
quality
-
the
quality
of
the
value




•	
canonical
data
type
-
the
data
type
of
the
value

This
actually
belongs
to
the
property

see
Property

but
it
is
mirrored
at
the
item




•	
access
rights
-
tells
if
the
value
is
read
only

write
only

or
both
read
write

The
access
right
is
common
for
all
item
values
and
belongs
to
the
item




•	
scan
rate
-
the
fastest
rate
with
which
the
value
can
be
expected
to
be
updated

The
scan
rate
is
common
for
all
item
values
and
belongs
to
the
item





For
an
information
model
describing
this
refer
to
Section
4
1
1

“Nodes

Items

Types


and
Properties
?
on
page
4-2
and
Section
4
1
3

“Item
Values
?
on
page
4-4



Each
item
has
a
universal
identity
given
by
its
ItemID

The
ItemID
is
made
up
of
the
ResourceID
of
a
node
and
the
PropertyID
of
a
property

The
ItemID
of
an
item
is
the
same
in
all
views
provided
by
a
DAIS
server

Clients
may
construct
ItemIDs
given
the
identities
of
nodes
and
properties


DAIS
servers
may
be
coordinated
with
DAF
servers
so
that
valid
ItemIDs
can
be
constructed
from
DAF
ResoureIDs


Within
each
view
provided
by
the
server

an
item
has
a
label
that
is
unique
among
all
items
belonging
to
the
same
node

Within
each
view

an
item
has
a
unique
pathname


The
pathname
is
a
string
that
contains
the
item’s
label
and
the
pathname
of
its
node


The
pathname
must
be
a
valid
URI

but
apart
from
that
the
syntax
of
pathnames
is
implementation
dependent


Note
–
In
OPC
the
pathname
is
the
primary
way
to
identify
items
and
is
called
the
ItemID

In
DAIS
the
ResourceID

PropertyID
pair
is
the
primary
identification
and
so
it
is
called
the
ItemID

This
is
a
potential
point
of
confusion

The
two
ItemIDs
play
approximately
the
same
role
in
OPC
and
DAIS
respectively

but
they
are
not
the
same
type


The
item
interfaces
permit
the
stock
of
items
to
be
browsed

Once
an
item
is
located

the
group
interfaces
are
used
to
deliver
its
values

selected
by
source

at
successive
times

In
addition

the
item
interfaces
provide
the
most
current
value
for
the
default
source

In
either
case
the
item
value
and
qualifications
are
represented
by
the
six
fundamental
attributes
listed
above


The
Item
IDL
defines
a
main
interface
Home
for
browsing
among
hierarchically
structured
items

leaf
nodes


The
information
model
describing
the
hierarchical
structure
is
found

in
Section
4
1
1

“Nodes

Items

Types

and
Properties
?
on
page
4-2





DAIS

DataAccess

Item

IHome
<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnam
es


get
ids


get
access
paths


11


11


0

0
n
n



0

0
n
n



Item
cache
value


SimpleV
alue
cache
value
last
updated


DateTim
e
cache
value
quality


DAIS

Quality
scan
rate


unsigned
long
access
rights


DAIS

AccessRights
NodeItem
Component

fro
m
DA
IS
Nod
e

pathname


string



DAIS

DataAccess

Item

Iterator
<<Interface>>
max
left


next
n


reset


clone


destroy



Figure
4-9
DAIS
data
access
item
IDL
in
UML










File

DAISItem
idl
#ifndef

DAIS
ITEM
IDL
#define

DAIS
ITEM
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
DataAccess
{
module
Item
{

struct
Description

{

ItemID
id


string
label


SimpleValue
value



includes
the
canonical
data
type

Quality
dais
quality


DateTime
time
stamp


AccessRights
access
rights


unsigned
long
scan
rate

}

typedef
sequence<
Description
>Descriptions


interface
Iterator
{

boolean
next
n






in

unsigned
long

n





out

Descriptions

items












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownResourceID
{string
reason
}

exception
UnknownItemID
{string
reason
}

exception
InvalidFilter
{string
reason
}

exception
InvalidValueType
{string
reason
}

exception
UnkownTypeID
{string
reason
}

exception
InvalidAccessRight
{string
reason
}


Description
find


in
ItemID
item


raises

UnknownItemID



Descriptions
find
each

in
ItemIDs
items


raises

UnknownItemID



Iterator
find
by
parent


in
ResourceID
node

in
string
filter
criteria

in
SimpleValueType
data
type
filter

in
AccessRights
access
rights
filter



raises

UnknownResourceID




InvalidFilter




InvalidValueType




InvalidAccessRight





Iterator
find
by
type





in
ResourceID

node




in
ResourceIDs

type
filter




in
string

filter
criteria




in
SimpleValueType

data
type
filter




in
AccessRights

access
rights
filter





raises

UnknownResourceID





InvalidFilter





InvalidValueType





UnkownTypeID





InvalidAccessRight






Strings
get
pathnames






in
ItemIDs

items










ItemIDs
get
ids






in
Strings

pathnames










Strings
get
access
paths






in
ItemID

item





raises

UnknownItemID






}
}
}
}





#endif




DAIS
ITEM
IDL




Description




A
struct
describing
an
item







Member

Description



id

The
identification
of
this
item




label

The
label

single
level
designation

of
the
item




value

The
current
value
sample
for
the
item

The
SimpleValue
also
contains
the
data
type




dais
quality

The
current
quality
of
the
value




time
stamp

The
time
stamp
for
the
value
sample




access
rights

States
if
the
value
is
read

write

or
both
read
and
write




scan
rate

States
the
highest
update
rate
that
can
be
expected




Iterator

Refer
to

Section
4
1
5

“Utility
SCADA
EMS
Measurement
Model
?
on
page
4-5

This

interface
corresponds
to
the
OPC
interface
EnumString
with
the
difference
that
the
Iterator
return
the
Description
struct
instead
of
a
single
string


IHome

An
object
used
for
browsing
items
and
corresponds
to
the
IOPCBrowseServerAddressSpace


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


UnknownItemID

An
exception
stating
that
the
resource
or
property
in
the
ItemID
is
unknown


For
methods
taking
a
sequence
of
item
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


InvalidFilter

An
exception
stating
the
filter
criteria
string
is
not
correct

The
likely
reason
behind
this
exception
is
an
erroneously
entered
string


InvalidValueType

An
exception
stating
that
the
SimpleValueType
does
not
exist


UnknownTypeID

An
exception
stating
one
or
more
TypeIDs
does
not
exist


InvalidAccessRight

An
exception
stating
that
the
access
rights
do
not
exist


find



For
a
given
item
browse
position

return
information
about
that
item




Parameter

Description



item

An
item
identification




return

The
item
description




find
each




For
a
sequence
of
items

return
information
about
each
item




Parameter

Description



items

A
sequence
of
item
identifications




return

An
iterator
holding
the
item
descriptions




find
by
parent




For
a
given
node
identification

return
child
items
to
that
node

Hence
to
reach
all
items
using
this
method
repeated
calls
must
be
made
for
each
node
level

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
LEAF




Parameter

Description



node

The
parent
node
identification




filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
only
items
with
pathnames
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





data
type
filter

Select
items
having
the
specified
canonical
data
type




access
rights
filter

Select
items
having
the
specified
access
rights




return

An
iterator
holding
item
descriptions
for
items
•
that
are
child
to
the
parent
node

•
matching
the
filter
criteria

data
type
filter

and
access
rights
filter




find
by
type



For
a
sub-tree
given
by
the
node
parameter

return
all
child
items
matching
the
filter
criteria

This
will
return
all
items
under
the
given
sub-tree
root
node

This
will
make
the
items
in
the
sub-tree
to
appear
flattened
out

This
corresponds
to
the
OPC
method
BrowseOPCItemIDs
with
the
parameter
dwBrowseFilterType
set
to
OPC
FLAT




Parameter

Description



node

The
identification
for
the
node
defining
the
sub-tree




type
filter

Select
nodes
in
the
sub-tree
having
a
type
matching
any
of
the
types
listed
in
the
type
filter






filter
criteria


A
server
specific
filter
string

This
is
entirely
free
format
and
may
be
entered
by
the
user
via
a
text
field

An
empty
string
indicates
no
filtering

The
filter
selects
only
items
with
pathnames
matching
the
filter
criteria

For
a
description
of
the
filter
refer
to
Section
3
1
11

“Filter
Definitions
?
on
page
3-25





data
type
filter

Select
items
having
the
specified
canonical
data
type




access
rights
filter

Select
items
having
the
specified
access
rights




return

An
iterator
holding
item
descriptions
for
items
•
that
are
child
to
nodes
in
the
sub-tree
and
nodes
having
a
type
matching
the
type
filter

•
matching
the
filter
criteria

data
type
filter

and
access
rights
filter




get
pathnames



Translate
a
sequence
of
item
identifications
to
the
corresponding
sequence
of
pathnames

If
an
item
fails
to
translate
to
a
pathname

due
to
an
unknown
identification


the
corresponding
pathname
is
an
empty
string




Parameter

Description



items

The
sequence
of
items




return

The
corresponding
sequence
of
pathnames




get
ids



Translate
a
sequence
of
pathnames
to
the
corresponding
sequence
of
item
identifications

If
a
pathname
fails
to
translate
to
an
item
identification

due
to
an
unrecognized
pathname

the
corresponding
item
identification
is
NULL


get
access
paths



Get
the
possible
communication
paths
how
data
can
be
retrieved
for
the
node

An
access
path
is
expected
to
be
human
readable
so
that
a
human
can
pick
one
and
feed
it
back
to
the
server
as
the
preferred
path

via
other
interfaces





Parameter

Description



item

An
item
identification




return

A
sequence
of
possible
access
paths
for
the
item




Browsing
Items





Client

Client


DAIS

DataAccess

Item

IHome

DAIS

DataAccess

Item

IHome


DAIS

DataAccess

Item

Iterator

DAIS

DataAccess

Item

Iterator

DAIS

DataAccess

Session

DAIS

DataAccess

Sessionnode
home



find
by
parent



next
n



item
home



find
by
parent



Get
the
items
for
a
particular
node
Get
some
item
descriptions
for
the
particular
node
Get
the
items
for
another
node
Get
some
node
of
interest

refer
to
browsing
of
Nodes

Figure
4-10
Browsing
items
interaction
Navigate
across
associations

find
by
parent








Client
Client


DAIS

DataAccess

Item

IHome

DAIS

DataAccess

Item

IHomeataccess

Node

IHomea

DAIS

DA

DAIS

DtaAccess

Node

IHomeGet
information
about
each
item
at
a
known
node
find



Pick
an
item
holding
a
ResourceID
and
get
the
node
information
for
that
ResourceID
find
by
parent



Get
the
item
information
for
the
new
node

Figure
4-11
Navigating
across
associations
interaction















These
are
definitions
for
transmitting
item
values
to
clients

Interfaces
are
defined
for
server
side
read
and
write
operations
and
client
side
callback
operations

Clients
shall
implement
the
Callback
object
for
the
server
to
use
at
transfer
of
data

A
client
may
have
any
number
of
callback
objects

The
client
shall
connect
each
callback
object
to
a
server
object
implementing
ConnectionPoint


The
IO
interfaces
support
three
different
ways
to
read
data
and
two
different
ways
to
write
data




Read
data



•	
Synchronous
read
where
the
data
is
received
at
return
from
the
sync
read


method




•	
Asynchronous
read
where
the
data
is
returned
at
the
Callback
object




•	
Subscription
where
data
is
sent
spontaneously
by
the
server
at
the
callback
object








Write
data



•	
Synchronous
write
returning
to
the
client
once
all
the
written
data
has
reached
the
devices



•	
Asynchronous
write
returning
when
the
data
is
received
by
the
DAIS
server

A
callback
on
Callback
is
sent
by
the
server
once
the
written
data
has
reached
the
devices




Each
item
value
is
transmitted
in
a
struct
with
a
timestamp
and
quality
indication

A
sequence
of
this
struct
is
either
sent
via
the
callback
object
or
directly
in
read
or
write
calls


In
OPC
the
IO
interface
corresponds
to
the
OPC
interfaces
IOPCSyncIO

IOPCAsyncIO

and
IOPCDataCallback




DAIS

DataAccess

IO

SyncIO
<<Interface>>
sync
read


sync
write


DAIS

DataAccess

IO

ConnectionPoint
<<Interface>>
callback




DAIS

DataAccess

IO

Callback
callback
callback


DAIS

DataAccess

IO

Callback




11


0

0
1
1



DAIS

DataAccess

IO

Callback
<<Interface>>
on
data
change


on
read
complete


on
write
complete


on
cancel
complete


0

*0

*


11



Client

from
DAIS
Server




DAIS

DataAccess

IO

AsyncIO
<<Interface>>
async
read


async
write


refresh


cancel


set
enable


get
enable


DAIS

DataAccess

IO

ItemState
<<struct>>
client
handle


ClientItemHandle
time
stamp


DateTime
dais
quality


DAIS

Quality
value


SimpleValue

Figure
4-12
DAIS
data
access
IO
IDL
in
UML

The
DAISConnectionPoint
callback


methods
correspond
to
a
get
or
set
method
for
the
callback
attribute













File

DAISDAIO
idl#ifndef

DAIS
DAIO
IDL#define

DAIS
DAIO
IDL#pragma
prefix
"omg
org"#include
<DAISCommon
idl>
module
DAIS
{

module
DataAccess
{module
IO
{
enum
DataSource
{


DS
CACHE



DS
DEVICE

}


struct
ItemState

{
SimpleValue
value

DateTime
time
stamp

Quality
dais
quality

ClientItemHandle
client
handle


}
typedef
sequence<ItemState>
ItemStates

struct
ItemUpdate
{
ServerItemHandle
server
handle

SimpleValue
value


}
typedef
sequence<ItemUpdate>
ItemUpdates

interface
SyncIO{
ItemStates
sync
read


in
DataSource
data
source

in
ServerItemHandles
server
handles

out
ItemErrors
errors





ItemErrors
sync
write





in

ItemUpdates
updates










}





typede
f
unsi
gned
long

CancelID




int

erface
AsyncIO



{






exception
NotConnected{string
reason
}

exception
InvalidCancelID{string
reason
}

exception
NotActive{string
reason
}


CancelID
async
read


in
ServerItemHandles
server
handles

in
DataSource
data
source

in
unsigned
long
transaction
id



raises

NotConnected

NotActive



CancelID
async
write


in
ItemUpdates
updates


in
unsigned
long
transaction
id


raises

NotConnected



CancelID
refresh



in
DataSource
data
source



raises

NotConnected
NotActive



void
cancel


in
CancelID
cancel
id
in
unsigned
long
transaction
id



raises

InvalidCancelID



attribute
boolean
enabled

}


interface
Callback
{

void
on
data
change


in
unsigned
long
transaction
id

in
boolean
all
quality
good

in
ItemStates
states





void
on
read
complete


in
unsigned
long
transaction
id

in
boolean
all
quality
good

in
ItemStates
states

in
ItemErrors
errors





void
on
write
complete


in
unsigned
long
transaction
id

in
ItemErrors
errors





void
on
cancel
complete







in

unsigned
long

transaction
id













}








interface
ConnectionPoint
{

attribute
Callback
cllbck

}
}
}
}

#endif




DAIS
DAIO
IDL
DataSource



Member

Description



DS
CACHE

Data
cached
in
the
server
is
requested




DS
DEVICE

Data
from
the
device
is
requested

This
will
force
a
read
from
the
device
or
RTU

A
read
from
device
will
be
made
regardless
of
the
group
or
item
active
status
and
no
group
NotActive
exception
will
be
forced




ItemState

The
struct
is
the
major
carrier
of
data
conveyed
over
the
interface

It
is
the
“message?
holding
the
payload




Member

Description



value

The
value
itself




time
stamp

The
time
stamp
when
the
value
was
last
updated




quality

The
quality
for
the
value




client
handle

A
client
side
handle
enabling
the
client
to
make
a
quick
look
up
of
the
item
in
its
internal
data
structures




ItemUpdate

The
struct
carry
an
update
for
an
item




Member

Description



server
handle

A
server
side
handle
enabling
the
server
to
make
a
quick
look
up
of
the
item
in
its
internal
data
structures




value

The
value
that
shall
be
used
in
the
update




SyncIO

An
interface
for
the
synchronous
operations


sync
read



Synchronous
read
of
items

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




Parameter

Description



data
source

The
source
from
where
to
read
the
data




server
handles

A
sequence
specifying
the
whole
or
a
subset
of
the
server
side
handles
as
defined
via
the
DAIS

GroupEntry

Manager
interface




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
INVALID
DAIS
HANDLE



return

A
sequence
of
ItemStates
for
the
items




sync
write



Synchronous
write
of
item
values
to
devices

not
the
internal
server
cache


The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
all
or
a
subset
of
the
items
defined
for
a
GroupEntry

Manager

The
ItemUpdate

value
member
is
used
to
update
the
items
in
devices




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
INVALID
DAIS
HANDLE
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



AsyncIO

An
interface
for
asynchronous
read
or
write
operations


NotConnected

An
exception
telling
that
there
is
no
callback
object
connected
by
the
client


InvalidCancelID

An
exception
telling
that
the
supplied
cancel
id
number
is
not
recognized


NotActive

An
exception
telling
that
the
group
or
all
items
in
the
group
is
inactive

Only
issued
when
read
from
cache


async
read



Asynchronous
read
of
items
from
devices

OPC
may
report
read
errors
both
at
return
from
async
read


and
at
on
read
complete



DAIS
will
report
all
errors
at
on
read
complete







Parameter

Description



server
handles

A
sequence
specifying
the
whole
or
a
subset
of
the
server
side
handles

as
defined
via
the
DAIS

GroupEntry

Manager
interface




data
source

The
source
from
where
to
read
the
data

When
reading
from
cache

inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
read
operation




async
write



Asynchronous
write
of
item
values
to
devices

not
the
internal
server
cache


OPC
may
report
write
errors
both
at
return
from
async
write


and
at
on
write
complete



DAIS
will
report
all
errors
at
on
write
complete






Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
all
or
a
subset
of
the
items
defined
for
a
DAIS

GroupEntry

Manager

The
ItemUpdate

value
member
is
used
to
update
the
items
in
devices




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
write
operation




refresh



Initiate
a
complete
asynchronous
read
transfer
for
all
item
entries
defined
via
the

DAIS

DataAccess

GroupEntry

Manager
interface

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE


The
cyclic
on
data
change
reporting
continues
unaffected
by
a
refresh
call

However

items
still
unchanged
after
a
refresh
will
not
be
reported
in
a
succeeding
on
data
change
call




Parameter

Description



data
source

The
source
from
where
to
read
the
data




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
data
change
call




return

A
cancellation
number
unique
for
the
client

The
number
is
used
by
a
client
to
cancel
an
ongoing
asynchronous
refresh
operation




cancel



Cancel
on
ongoing
refresh

async
read

or
async
write
operations

The
server
is
expected
to
acknowledge
a
successfully
initiated
cancel
operation
with
an
on
cancel
complete


callback




Parameter

Description



cancel
id

The
server
generated
cancellation
number
for
the
operation




to
cancel




enable

An
attribute
used
to
enable
or
disable
the
spontaneous
on
data
change


callbacks

The
enable
state
does
not
affect
on
data
change
response
to
refresh
calls

When
a
group
is
created
it
is
enabled
by
default


Callback

An
interface
implemented
by
the
client
and
used
by
the
server
to
send
data
to
the
client


on
data
change



The
method
is
called
by
the
server
when
spontaneous
changes
occur
or
when
the
client
has
requested
an
explicit
refresh

Only
active
items
are
reported
in
spontaneous
calls




Parameter

Description



transaction
id

If
the
call
is
in
response
to
a
refresh

the
transaction
number
for
that
refresh
call

If
the
call
is
autonomous
due
to
one
or
more
spontaneous
changes

the
number
is
zero




all
quality
good

All
item
quality
values
are
good




item
states

A
sequence
of
requested
or
spontaneously
changed
ItemStates




on
read
complete



The
method
is
used
by
the
server
to
report
data
in
response
to
an
asynchronous
read




Parameter

Description



transaction
id

The
transaction
number
for
the
corresponding
read




all
quality
good

All
item
quality
values
are
good

This
requires
that
no
errors
are
reported
in
the
error
parameter
below




item
states

A
sequence
of
ItemStates
matching
the
read
operation




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
initially
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
ERROR
INVALID
DAIS
HANDLE



on
write
complete



The
method
is
used
to
report
the
success
of
an
asynchronous
write
operation




Parameter

Description



transaction
id

The
transaction
number
for
the
corresponding
write




errors

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
all
write
operations
initially
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
INVALID
DAIS
HANDLE
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



on
cancel
complete



The
method
is
used
to
acknowledge
the
completion
of
a
successfully
initiated
cancel
call




Parameter
Description
transaction
id
The
transaction
number
for
the
corresponding
cancel


ConnectionPoint

An
interface
used
by
the
client
to
connect
or
disconnect
a
client
callback
object
at
the
server


callback

An
attribute
referencing
the
callback
object


In
an
implementation
one
get
and
one
set
method
will
implement
the
callback
attribute

Due
to
limitation
in
the
UML
tool
used
to
draw
the
diagrams

the
attribute
is
represented
by
the
two
methods
connect
and
disconnect














A
group
has
a
collection
of
group
entries

Each
group
entry
associates
the
group
with
an
item

An
ItemID
identifies
a
group
entry
within
its
group

The
pathname
of
an
item
may
be
used
as
an
alternative
to
the
ItemID
when
the
group
entry
is
created

see

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15




In
OPC
the
GroupEntry
interface
corresponds
to
the
interface
IOPCItemMgt







DAIS

DataAccess

GroupEntry

Manager
<<Interface>>
create
entries


validate
entries


remove
entries


set
active
state


set
inactive
state


set
client
handles


set
data
types


create
group
entry
iterator





11



0

0
n
n


11


0

0
*
*



GroupEntry
pathname


string
item


DAIS

ItemID
active


boolean
access
path


string
client
handle


ClientItemHandle
requested
data
type


SimpleValueType
access
rights


AccessRights
canonical
data
type


SimpleValueType



DAIS

DataAccess

GroupEntry

Iterator
<<Interface>>
max
left


next
n


reset


clone


destroy



Figure
4-13
DAIS
data
access
group
entry
IDL
in
UML










File

DAISGroupEntry
idl
#ifndef

DAIS
GROUP
ENTRY
IDL
#define

DAIS
GROUP
ENTRY
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
DataAccess
{
module
GroupEntry
{

struct
Description



{



ServerItemIdentification

server
item
id




string

access
path




ClientItemHandle

client
handle




SimpleValueType

requested
data
type




boolean

active




}





typedef
sequence<Description
>

Descriptions




struct
DetailedDescription




{






ItemID

item





string

pathname





string

access
path





ServerItemHandle

server
handle




ClientItemHandle
client
handle
SimpleValueType
requested
data
type
SimpleValueType
canonical
data
type
AccessRights
access
rights
boolean
active

}
typedef
sequence<DetailedDescription>
DetailedDescriptions

struct
Result
{
ServerItemHandle
server
handle

ClientItemHandle
client
handle

AccessRights
access
rights

SimpleValueType
canonical
data
type


}
typedef
sequence<Result>
Results

struct
HandleAssociation
{
ServerItemHandle
server
handle

ClientItemHandle
client
handle


}

typedef
sequence<HandleAssociation>HandleAssociations


struct
DataTypeDescription

{
ServerItemHandle
server
handle

SimpleValueType
requested
data
type


}

typedef
sequence<DataTypeDescription>DataTypeDescriptions


interface
Iterator
{

boolean
next
n

in
unsigned
long
n
out
DetailedDescriptions
entries



void
reset



Iterator
clone



void
destroy




}


interface
Manager
{

Results
create
entries

in
Descriptions
entries
out
ItemErrors
errors




Results
validate
entries





in

Descriptions

entries




out

ItemErrors

errors










ItemErrors
remove
entries






in

ServerItemHandles

server
handles










ItemErrors
set
active
state






in

ServerItemHandles

server
handles










ItemErrors
set
inactive
state






in

ServerItemHandles

server
handles










ItemErrors
set
client
handles






in

HandleAssociations

handle
associations










ItemErrors
set
data
types






in

DataTypeDescriptions

descriptions










Iterator
create
group
entry
iterator



}
}
}
}
#endif




DAIS
GROUP
ENTRY
IDL

Description
The
struct
describes
a
group
entry
for
an
item

The
client
to
configure
new
entries
in
a
group
uses
it

It
directly
corresponds
to
the
OPCItemDef
struct




Member

Description



server
item
id

The
identification
of
the
item




access
path

The
access
path
used
by
the
server
to
connect
to
the
device
and
sensor

An
empty
string
as
input
tells
the
server
to
select
the
access
path




client
handle

The
client
provided
handle
to
the
item




requested
data
type

The
data
type
requested
by
the
client
for
the
value




active

Tells
if
the
item
is
active
and
data
from
devices
is
updated
in
the
cache




DetailedDescription

The
struct
is
used
to
deliver
group
entry
information
to
the
client

In
OPC
this
is
made
with
the
struct
OPCITEMATTRIBUTES

Description
is
used
for
both
these
OPC
structs




Member

Description



item

The
item
identification
by
an
ItemID




pathname

A
string
concatenating
the
labels
for
all
nodes
in
the
path
from
the
item
up
to
the
root




access
path

The
access
path
used
by
the
server
to
connect
to
the
device
and
sensor

An
empty
string
as
input
tells
the
server
to
select
the
access
path




server
handle

Server
provided
handle
for
the
item




client
handle

Client
provided
handle
for
the
item




requested
data
type

The
data
type
requested
by
the
client
for
the
value




canonical
data
type

The
data
type
the
server
uses
internally
for
the
value




access
rights

The
access
rights

read

write

and
read-write




active

Tells
if
the
item
is
active
and
data
from
devices
is
updated
in
the
cache




Result

The
struct
is
used
to
transfer
the
result
from
a
create
entries


or
validate
entries


call
back
to
a
client

In
OPC
the
corresponding
struct
is
OPCITEMRESULT




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




client
handle

The
supplied
client
handle
for
the
item




access
rights

The
access
rights

read

write

and
read-write




canonical
data
type

The
data
type
the
server
uses
internally
for
the
value




HandleAssociation

The
struct
is
used
to
change
the
association
between
server
handles
and
client
handles
in
the
set
client
handle


method




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




client
handle

The
new
client
handle
wanted
by
the
client




DataTypeDescription

The
struct
is
used
to
change
the
data
type
of
the
value
delivered
in
the
ItemState
struct




Member

Description



server
handle

The
handle
given
to
the
client
for
the
item




requested
data
type

The
new
data
type
wanted
by
the
client




Iterator

Refer
to

Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10

The
interface
directly

corresponds
to
the
EnumOPCItemAttributes
interface


Manager

An
interface
for
creation
and
browsing
of
group
entries

The
interface
directly
corresponds
to
the
IOPCItemMgt
interface


create
entries



Adds
one
or
more
entries
to
a
group




Parameter

Description



entries

Group
entry
descriptions
for
entries
to
be
created




errors

A
sequence
of
structs
reporting
the
items
that
were
not
entered
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
UNKNOWN
PATHNAME
•
ERROR
BAD
TYPE
•
ERROR
UNKNOWN
ACCESS
PATH



return

A
sequence
of
result
descriptions
for
the
entries
that
were
entered
in
the
group




validate
entries



Is
used
to
determine
if
an
item
is
valid

could
it
be
added
without
error


Also
returns
information
about
the
item
such
as
canonical
datatype

Does
not
affect
the
group
in
any
way




Parameter

Description



entries

Group
entry
descriptions
for
entries
to
be
validated




errors

A
sequence
of
structs
reporting
the
items
that
could
not
be
validated
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
UNKNOWN
PATHNAME
•
ERROR
BAD
TYPE
•
ERROR
UNKNOWN
ACCESS
PATH



return

A
sequence
of
result
descriptions
for
the
entries
that
were
validated




remove
entries



Used
to
remove
entries
from
a
group




Parameter

Description



server
handles

Server
handles
for
entries
that
shall
be
removed




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
removed
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
active
state



Used
to
activate
individual
items
in
a
group

Activate
state
means
that
the
server
acquires
data
from
devices

Inactive
state
means
that
the
server
does
not
acquire
any
data

The
group
enable
state
control
if
acquired
data
shall
be
sent
further
to
subscribers
via
on
data
change




Parameter

Description



server
handles

Server
handles
for
items
to
activate




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
activated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
inactive
state



Used
to
deactivate
individual
items
in
a
group




Parameter

Description



server
handles

Server
handles
for
items
to
deactivate




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
deactivated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
client
handles



Used
to
change
the
client
handles
for
items




Parameter

Description



handle
associations

Change
descriptions
for
the
items
where
to
change
the
client
handles




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
updated
due
to
an
error

Reported
error
s


•
ERROR
UNKNOWN
ITEMID



set
data
types



Used
to
change
the
requested
data
types
for
items




Parameter

Description



descriptions

Change
descriptions
for
the
items
where
to
change
the
data
types




return

A
sequence
of
structs
reporting
the
items
that
were
not
recognized
or
could
not
be
updated
due
to
an
error

Reported
errors
are

•
ERROR
UNKNOWN
ITEMID
•
ERROR
BAD
TYPE



create
group
entry
iterator



Used
to
create
a
group
entry
iterator

Used
by
clients
to
inspect
existing
group
entries




Parameter
Description
return
The
GroupEntry
Iterator
















A
group
is
a
collection
of
items
and
a
connection
to
one
or
more
consumers
of
item
values

Clients
create
groups
and
their
lifetime
is
bounded
by
the
session
to
which
they
belong


See

Section
4
2
2

“DAISDASession
IDL
?
on
page
4-8




The
purpose
of
a
group
is
to
convey
selected
item
values
to
a
client

A
callback
object

may
be
connected
to
a
group
to
receive
item
value
information

see
Section
4
2
5


“DAISDAIO
IDL
?
on
page
4-23


Items
may
be
added
and
removed
from
a
group
as

group
entries

see

Section
4
2
6

“DAISGroupEntry
IDL
?
on
page
4-32


A
group
has
an

update
rate
that
determines
how
frequently
updated
values
for
its
entries
are
notified
to
its
connected
callback
objects

A
group
also
has
other
states
that
control
its
notification
behavior


A
group
may
also
be
initialized
with
a
predefined
set
of
entries

A
set
of
entries
is
called
a
public
group
and
is
identified
by
a
ResourceID

A
client
can
create
or
remove
public
groups

A
server
may
represent
a
public
group
as
a
node
such
that
the
ResourceID
of
the
public
group
and
the
node
are
identical

This
would
allow
clients
to
locate
public
groups
by
name


The
DAIS


DataAccess

Group

Manager
object
implements
interfaces
from
the
DAISDAIO
and
DAISGroupEntry
IDLs

This
is
specified
by
inheritance
of
interfaces
as
seen
in

Figure
4-14


A
DAIS

DataAccess

Group

Manager
has
a
state
given
by
the
DAIS

DataAccess

Group

State
struct
and
a
DAIS

DataAccess

Group

Manager
object
is
created
from
the
DAIS

DataAccess

Group

IHome
object


In
OPC
the
Group
interface
corresponds
to
the
interfaces
IOPCGroupStateMgt
and
IOPCPublicGroupStateMgt




DAIS

DataAccess

IO

ConnectionPoint

from
DAISDAIO

<<Interface>>
callback




DAIS

DataAccess

IO

Callback
callback
callback


DAIS

DataAccess

IO

Callback




11



0

10

1



DAIS

DataAccess

IO

Callback

from
DAISDAIO

<<Interface>>



DAIS

DataAccess

IO

SyncIO

from
DAISDAIO

<<Interface>>
sync
read


sync
write


DAIS

DataAccess

IO

AsyncIO

fromDAISDAIO

<<Interface>>
async
read


async
write


refresh


cancel


set
enable


get
enable


DAIS

DataAccess

GroupEntry

Manager

from
DAISGrou
pEntry

<<Interface>>
create
entries


validate
entries


remove
entries


set
active
state


set
inactive
state


set
client
handles


set
data
types


create
group
entry
iterator





DAIS

DataAccess

GroupEntry

Iterator

from
DAISGroupEntry

<<Interface>>



0

*0

*


11



DAIS

DataAccess

Group

Manager
<<Interface>>
get
state


set
state


clone


clone
group
to
public


destroy





0

n0

n



11



DAIS

DataAccess

Group

IHome
<<Interface>>
find
public
groups


find


create
group


clone
group
from
public


remove
public
group





11



11



DAIS

DataAccess

Group

State
update
rate


unsigned
long
active


boolean
time
bias


long
percent
dead
band


double
locale
id


unsigned
long
name


string

Figure
4-14
DAIS
data
access
group
IDL
in
UML










File

DAISGroup
idl
#ifndef

DAIS
GROUP
IDL
#define

DAIS
GROUP
IDL
#pragma
prefix
"omg
org"

#include
<DAISCommon
idl>
#include
<DAISGroupEntry
idl>
#include
<DAISDAIO
idl>

module
DAIS
{
module
DataAccess
{
module
Group
{

exception
DuplicateName
{string
reason
}


struct
State
{




string

name





unsigned
long

update
rate





boolean

active





long

time
bias





double

percent
deadband





unsigned
long

locale
id




}






struct
PublicGroupDescription

{
ResourceID
id

State
group
state


}

typedef
sequence<PublicGroupDescription>PublicGroupDescriptions


interface
Manager


GroupEntry

Manager

IO

AsyncIO

IO

SyncIO

IO

ConnectionPoint

{

State
get
state





unsigned
long
set
state


in
State
group
state


raises

DuplicateName



Manager
clone


in
string
name


raises

DuplicateName



PublicGroupDescription
clone
group
to
public


in
string
name


raises

DuplicateName



void
destroy




}

interface
IHome
{

exception
UnknownResourceID
{string
reason
}


PublicGroupDescriptions
find
public
groups




PublicGroupDescription
find

in
ResourceID
public
group


raises

UnknownResourceID


Manager
create
group



in
State
group
state


out
unsigned
long
revised
update
rate



raises

DuplicateName



Manager
clone
group
from
public



in
ResourceID
public
group


in
string
name



raises

DuplicateName

UnknownResourceID



void
remove
public
group



in
ResourceID
public
group



raises

UnknownResourceID


}
}
}
}

#endif




DAIS
GROUP
IDL

DuplicateName

An
exception
raised
when
an
object
is
created
and
the
name
already
exists

No
object
is
created
if
the
exception
is
raised

Used
for
session
and
group
manager
objects


State

The
struct
contains
information
about
the
group
state




Members

Description



name

Within
the
session
and
public
groups

unique
name
of
the
group




update
rate

Update
rate
for
the
group
in
milliseconds

When
used
as
input
it
specifies
the
fastest
rate
at
which
data
changes
may
be
sent
to
on
data
change


for
items
in
this
group

This
also
indicates
the
desired
accuracy
of
cached
data

This
is
intended
only
to
control
the
behavior
at
the
interface

How
the
server
deals
with
the
update
rate
and
how
often
it
actually
polls
the
hardware
internally
is
an
implementation
detail

Passing
0
indicates
the
server
should
use
the
fastest
practical
rate






active

Indicates
if
the
group
is
active
and
data
from
devices
is
updated
in
the
cache




time
bias

The
time
bias
in
minutes
for
the
group

A
zero
value
when
used
as
input
will
tell
the
server
to
use
the
default
system
time
bias

This
bias
behaves
like
the
Bias
field
in
the
Win32
TIME
ZONE
INFORMATION
structure




percent
deadband

The
percent
change
for
an
item
value
that
will
cause
a
call
back
for
that
value

This
parameter
only
applies
to
items
in
the
group
that
are
of
analog
type

If
a
client
specifies
a
zero
deadband

the
value
will
be
reported
with
the
update
rate




locale
id

The
localization
number
for
the
language
used
when
returning
string
values




Manager

An
object
used
to
manage
a
group

It
has
a
set
of
methods
related
to
the
group
itself

It
also
inherits
methods
from
interfaces
for
group
entry
management
and
data
transfer

For

group
entry
management
refer
to
Section
4
2
6

“DAISGroupEntry
IDL
?
on
page
4-32

and
for
data
transfer
refer
to

Section
4
2
4

“DAISItem
IDL
?
on
page
4-15

The

DAIS

DataAccess

Group

Manager
interface
corresponds
to
the
IOPCGroupStateMgt
interface


get
state



The
method
gets
the
group
status




Parameter
Description
return
State

set
state



The
method
sets
the
group
status




Parameter

Description



group
state

The
State
with
the
updates

All
members
will
be
updated

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
update
is
made




return

The
closest
update
rate
the
server
is
able
to
provide
for
the
group




clone



Create
a
copy
of
a
group




Parameter

Description



name

The
name
to
be
given
for
the
new
group

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
clone
is
created




return

A
description
of
the
public
group




clone
group
to
public




Create
a
public
copy
of
a
group
including
all
items
and
the
group
state




Parameter

Description



name

The
name
to
be
given
for
the
new
group

If
the
name
already
exists

a
DuplicateName
exception
is
raised
and
no
public
group
is
created




return

A
description
of
the
public
group




destroy



Delete
the
group


PublicGroupDescription

A
struct
describing
public
groups




Member

Description



id

A
ResourceID
identifying
the
public
group




group
state

The
group
state
struct
including
the
group
name




IHome

The
factory
object
for
groups

The
corresponding
OPC
interface
is
IOPCServer


UnknownResourceID

An
exception
telling
that
the
ResourceID
is
unknown

For
methods
taking
a
sequence
of
resource
ids
the
first
found
unknown
id
is
reported

The
likely
reason
behind
this
exception
is
some
misunderstanding
between
the
server
and
client
code
due
to
a
programming
error


find
public
groups



Find
all
public
groups
defined
in
the
server




Member
Description
return
A
sequence
of
public
group
descriptions


find



For
a
given
public
group

return
information
about
that
group




Member

Description



public
group

A
ResourceID
identifying
the
public
group




return

A
public
group
description




create
group



Create
a
new
initially
empty
group




Parameter

Description



group
state

The
State
to
be
set
for
the
new
group




revised
update
rate

The
closest
update
rate
the
server
is
able
to
provide
for
the
group




return

The
new
group




clone
group
from
public



Create
a
copy
from
a
public
group
having
an
existing
set
of
entries
and
state




Parameter

Description



public
group

The
identification
of
the
public
group




name

The
name
of
the
new
group




return

The
new
group




remove
public
group



Remove
a
public
group




Parameter

Description



public
group

The
identification
of
the
public
group




return

None



Group
management





Client
Client


DAIS

DataAccess

Session

DAIS

DataAcce
Grup

IHome
Gss

Session


DAIS

DataAccess
o

DAIS

DataAccess
roup

IHome


DAIS

DataAccess

Group

Manager

DAIS

DataAccess

Group

Managergroup
home



create
group



create
entries



Do
work
with
group
manager

e
g

activate
subscription
destroy




Figure
4-15
Group
management
interaction

Activate
subscription





Client

Client


DAIS

DataAccess

Group

Manager
DAIS

DataAccess

Group

Managerss
IO

Callbacks

DAIS

DataAcce

DAIS

DataAcces

IO

Callbackcallback
DAISDACallback

refresh



on
data
change



Forced
by
refresh
on
data
change



Spontaneous
on
data
change



Spontaneous

Figure
4-16
Active
subscription
interaction
Activate
a
subscription
silently





Client

Client


DAIS

DataAccess

Group

Manager

DAIS

DataAccess

Group

Managerss
IO

Callbacks

DAIS

DataAcce


DAIS

DataAcces

IO

Callbackset
inactive
state



callback



set
enable



set
active
state



Disable
refresh



on
data
change



set
enable



Enable
on
data
change




Figure
4-17
Activate
a
subscription
silently
interaction
Cancel





DAIS

DataAccess

Group

M
anager
DAIS

DataAccess

Group

Manager


DAIS

DataAccess

IO

Callback

DAIS

DataAccess

IO

CallbackCancel
refresh
operation
Cancel
async
read
Cancel
async
write


Client

Clienton
cancel
complete



on
cancel
complete



on
cancel
complete




refresh




cancel




async
read




cancel




async
write




cancel




Figure
4-18
Cancellation
interaction















The
purpose
of
the
interface
is
to
provide
a
simple
read
and
write
of
data

The
functionality
is
the
same
as
the
synchronous
read
and
write
described
in

Section
4
2
5


“DAISDAIO
IDL
?
on
page
4-23

but
without
having
to
create
a
group











File

DAISDASimpleIO
idl#ifndef

DAIS
DA
SIMPLE
IO
IDL#define

DAIS
DA
SIMPLE
IO
IDL#include
<DAISCommon
idl>
module
DAIS
{module
DataAccess
{module
SimpleIO
{
enum
DataSource
{


DS
CACHE



DS
DEVICE

}


struct
ItemError
{



}

typ
Error
ServerItemIdentification
string
edef
sequence<ItemError>

err

id

reason

ItemErrors




{
str
uct
ItemState





SimpleValue
DateTime
Quality
ServerItemIdentification

value

time
stamp

dais
quality

id




}






typedef
sequence<ItemState>ItemStates


struct
ItemUpdate

{
ServerItemIdentification
id

SimpleValue
value


}
typedef
sequence<ItemUpdate>
ItemUpdates

interface
IHome
{
ItemStates
read


in
DataSource
data
source

in
ServerItemIdentifications
ids

out
ItemErrors
errors





ItemErrors
write
with
qt


in
ItemStates
updates




ItemErrors
write


in
ItemUpdates
updates




}
}
}
}

#endif




DAIS
DA
SIMPLE
IO
IDL
DataSource

Find
all
public
groups
defined
in
the
server




Member

Description



DS
CACHE

Data
cached
in
the
server
is
requested




DS
DEVICE

Data
from
the
device
is
requested

This
will
force
a
read
from
the
device
or
RTU

A
read
from
device
will
be
made
regardless
of
the
group
or
item
active
status
and
no
group
NotActive
exception
will
be
forced




ItemError

A
struct
for
reporting
of
item
related
errors

The
struct
is
different
from
the
DAIS

ItemError
because
no
handles
are
used
to
identify
the
item
in
SimpleIO




Member

Description



err

An
error
code
as
described
for
DAIS

ItemError




id

The
identification
of
the
item




reason

An
additional
text
explaining
the
error




ItemState

The
struct
is
the
carrier
of
data
conveyed
over
the
interface

It
is
the
“message?
holding
the
payload

This
is
basically
the
same
struct
as
DataAccess

IO

ItemState
with
the
difference
that
instead
of
a
handle
for
identification
the
full
server
identification
is
used




Member

Description



value

The
value
itself




time
stamp

The
time
stamp
when
the
value
was
last
updated




quality

The
quality
for
the
value




id

The
identification
of
the
value
in
the
server




ItemUpdate

The
struct
carries
an
update
for
an
item




Member

Description



id

The
identification
of
the
value
in
the
server




value

The
value
that
shall
be
used
in
the
update




IHome

The
interface
for
simple
IO
operations


read

Synchronous
read
of
items

Inactive
items
will
be
reported
with
OPCQuality
set
to
OPC
QUALITY
OUT
OF
SERVICE




Parameter

Description



data
source

The
source
from
where
to
read
the
data

see
DataSource
above




ids

A
sequence
specifying
the
server
identifications
to
read




errors

A
sequence
reporting
items
for
which
the
read
failed

An
empty
sequence
indicates
all
read
operations
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
write
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID



return

A
sequence
of
ItemStates
for
the
items




write
with
qt

Synchronous
write
of
item
values
including
quality
and
time
stamp

The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemStates
specifying
the
updates
including
time
stamp
and
quality




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE



write

Synchronous
write
of
item
values
only

The
active
state
of
the
group
or
the
items
is
ignored




Parameter

Description



updates

A
sequence
of
ItemUpdates
specifying
the
update
values




return

A
sequence
reporting
items
for
which
the
write
failed

An
empty
sequence
indicates
write
operations
for
all
items
succeeded

Reported
errors
are

•
ERROR
BAD
RIGHTS

item
is
read
only

•
ERROR
UNKNOWN
PATHNAME
•
ERROR
UNKNOWN
ITEMID
•
ERROR
CLAMPED
•
ERROR
OUT
OF
RANGE
•
ERROR
BAD
TYPE









Contents

This
chapter
contains
the
following
sections




Section
Title

Page



“Information
Model?

5-2



“API?

5-6



The
alarms
&
events
interface
provides
a
client
with
a
way
to
subscribe
for
alarms
and
events
generated
within
RTUs

devices

or
any
software

The
server
supports
various
filter
functions
so
that
the
client
can
compose
a
filter
matching
its
current
interest
in
alarms
and
events

Once
the
client
sets
up
a
filter
specification
it
has
to
supply
the
server
a
callback
object
used
by
the
server
to
notify
the
client
with
generated
alarms
and
events


Events
just
reports
state
changes
while
alarms
have
an
associated
alarm
state
and
fault
state

Alarms
are
generated
with
the
intent
to
gain
attention
to
a
condition
that
needs
operator
intervention

Hence
alarms
and
events
are
recorded
and
presented
to
operators

Alarm
presentation
usually
involves
acoustic
annunciation
and
some
highlighting

e
g


red
color
and
or
blink

etc



An
operator
shall
acknowledge
the
alarm
state
and
the
fault
state
disappear
when
the
fault
causing
the
alarm
disappears


Equipment
and
functions
that
may
generate
alarms
and
events
are




•	
Process
instrumentation
making
sensor
data
and
actuation
capabilities
available




•	
Remote
terminal
units

RTUs

or
substation
control
systems

reading
sensor
data

and
controlling
actuators




•	
Process
communication
units
connecting
to
RTUs
or
substation
control
systems




•	
SCADA
subsystem
making
processed
sensor
data
and
control
capabilities
available
to
operators

applications

or
other
systems




•	
Energy
Management
System

EMS

-
subsystem
using
the
SCADA
subsystem
for
extended
processing
and
control





An
example
flow
of
alarms

events

and
acknowledgments
are
shown
in
Figure
5-1





SCADA
Application
Server
Instrumentation
RTU

Process
station
Server
Server
HMI
Data
traffic
for
use
cases
Alarms
and
Events
Acknowledgments

Figure
5-1
Alarms

events
and
acknowledgment
flows
in
a
SCADA
EMS





Alarms
and
events
are
generated
by
a
source
represented
by
Source

A
source
might
be
a
single
measurement

a
collection
of
measurements

or
some
other
object

A
collection
of
measurements
may
represent
a
complex
real
world
object
like
a
generator
or
some
control
function
for
the
generator

A
source
has
a
name
property

The
source
is
also
associated
with
a
type
that
describes
any
additional
properties

If
a
DAIS
server
implements
both
data
access
and
alarms
&
events

a
client
shall
expect
there
is
a
mapping
between
sources
and
nodes

A
client
shall
however
not
make
assumptions
on
how
the
mapping
is
made
and
use
the
method
translate
to
item
ids


to
get
the
mapping
from
the
server


Sources
are
organized
in
areas
represented
by
Area

An
area
typically
represents
area
of
responsibility
concerning
supervision
and
operation
of
sources

Areas
may
however
also
be
used
for
other
groupings
of
sources

Areas
can
be
hierarchically
structured
to
allow
creation
of
hierarchically
organized
responsibilities

Multiple
views
of
areas
are
supported


Alarms
and
events
are
categorized

Category
represents
the
categories

Three
main
categories
are
defined
and
must
be
implemented
by
a
server




•	
simple
-
describing
events
that
do
not
have
an
explicitly
modeled
condition
space




•	
tracking
-
describing
events
generated
due
to
an
operator
action




•	
condition
-
describing
events
generated
based
on
an
explicitly
modeled
condition
space




The
categories
simple
and
tracking
are
used
for
events

and
the
category
condition
is
used
for
alarms


For
each
main
category
it
is
possible
to
define
a
number
of
sub-categories

A
server
is
free
to
implement
any
sub-categories

Each
type
of
source
is
expected
to
be
associated
with
at
least
one
main
category
and
one
or
more
sub-categories
for
each
main
category

The
main
categories
are
not
expected
to
have
an
association
with
a
source
type

Subcategories
however
are
all
expected
to
have
an
associated
source
type


A
Condition
category
is
associated
with
one
or
more
condition
spaces

ConditionSpace
represents
a
condition
space

Depending
on
how
limits
are
applied
to
the
properties
defined
by
the
type
associated
with
a
condition
category
it
is
possible
to
create
a
space
consisting
of
different
discrete
conditions

Condition
describes
each
discrete
condition

A
condition
space
will
have
a
number
of
conditions
defined
for
it

A
Transition
describes
each
possible
transition
between
a
pair
of
conditions

The
alarms
&
event
session
does
not
however
provide
any
methods
for
direct
access
of
transitions

When
a
transition
is
traversed
a
condition
event
is
generated


A
source
may
be
associated
with
one
or
more
condition
spaces

Each
such
association
has
status
information
describing
the
current
condition

The
association
and
its
data
are
called
SourceCondition

The
source
condition
is
identified
by
its
associated
source
and
condition
space


A
source
is
of
a
specific
type

e
g


measurement

breaker

generator

tank

etc


and
the

type
has
one
or
more
properties
in
the
same
way
as
a
node

refer
to
Section
4
1
1


“Nodes

Items

Types

and
Properties
?
on
page
4-2


A
category
may
have
any
number

of
properties
associated
with
it

An
alarm
or
event
may
contain
values
for
the
properties
associated
with
the
corresponding
category

This
is
used
to
convey
additional
server
specific
information
with
alarms
and
events

Specification
of
what
properties
are
associated
with
categories
is
outside
the
scope
of
this
specification


The
described
classes
are
shown
in
Figure
5-2

The
attributes
are
described
later
with
the
description
of
the
interfaces




0

0
n
n



AreaSourceComponent

from
DAISAEArea

id


ResourceID
name


string
description


string
Area
Source

from
DAISAEArea



from
DAISAESourc
e


+aggregated
types

+parent

0

n0

n


0

0
n
n



Type

from
DAIST
ype




0

0
n
n


11



1

n1

n


11


0

0
n
n



Property

from
DAISProperty




0

n0

n



SourceCondition

from
DA
I
S
AES
o
urceCon
di
t
ion

condition
op
state


DAISConditionOpState
quality


DAIS

Quality
last
acknowledge


DateTime
condition
last
active


DateTime
condition
space
last
active


DateTime
condition
space
last
inactive


DateTime
acknowledger
name


string
comment


string



0

0
n
n



0

0
n
n



0

n0

n


11



1

n
11

n1



1

n1

n


0

0
n
n


11

+conditions



ConditionSpace

from
DAISAECondition
Space

id


ResourceID
name


string
description


string
Condition

from
DAISAECondition
Space

id
number


unsigned
long
name


string
description


string
severity


unsigned
long
condition
logic


string



SimpleCategory

fro
m
DAISAECate
gory

TrackingCategory

fro
m
DAISAECate
gory

ConditionEvent

from
DAISAEIO

ConditionCategory

fro
m
DAISAECate
gory

11Category

f
ro
m
DAIS
A
ECateg
ory




11


0

n0

n

+active
condition


11



Transition

from
DAISAECo
nditionSp
ac
e




0

n0

n

Figure
5-2
DAIS
Alarms
and
Events
Information
Model

The
objects
in
DAIS
alarms
and
events
has
the
following
mapping
to
OPC
alarms
and
events
objects




DAIS
A&E
object

OPC
A&E
object



Source

Source



Area

Area



Property

EventAttribute



Category

EventCategory



The
categories

simple

tracking
and
condition

EventType



ConditionSpace

Condition



Condition

SubCondition



SourceCondition

SourceCondition








In
OPC
there
is
a
recommendation
of
what
properties
are
expected
to
be
supported
by
an
alarm
&
event
server

The
recommended
properties
are
shown
in
Table
5-1

The
column
names
correspond
to
the
attributes
in
the
Property
class


Table
5-1
Recommended
Properties
Table
5-1
Recommended
Properties



label

id

canonical

data
type

description



Condition
Status

300

STRING
TYPE

The
current
alarm
or
condition
status
associated
with
the
Item

for
example

“NORMAL
?
“ACTIVE
?
“HI
ALARM?





Alarm
Quick
Help

301

STRING
TYPE

A
short
text
string
providing
a
brief
set
of
instructions
for
the
operator
to
follow
when
this
alarm
occurs




Alarm
Area
List

302

STRING
TYPE
sequence

An
array
of
strings
indicating
the
plant
or
alarm
areas
that
include
this
ItemID




Primary
Alarm
Area

303

STRING
TYPE

A
string
indicating
the
primary
plant
or
alarm
area
including
this
ItemID




Condition
Logic

304

STRING
TYPE


An
arbitrary
string
describing
the
test
being
performed

for
example

“High
Limit
Exceeded?
or
“TAG
PV
>=
TAG
HILIM?


Refer
to
Section
5
2
7
3

“Condition
Logic
?
on
page
5-38







Limit
Exceeded

305

STRING
TYPE

For
multistate
alarms

the
condition
exceeded

for
example

HIHI

HI

LO

LOLO





Deadband

306

DOUBLE
TYPE

Deadband



HiHi
Limit

307

DOUBLE
TYPE

HiHi
Limit



Hi
Limit

308

DOUBLE
TYPE

Hi
Limit



Lo
Limit

309

DOUBLE
TYPE

Lo
Limit



LoLo
Limit

310

DOUBLE
TYPE

LoLo
Limit



Rate
of
Change
Limit

311

DOUBLE
TYPE

Rate
of
Change
Limit



Deviation
Limit

312

DOUBLE
TYPE

Deviation
Limit




3124999


Reserved
by
OPC


















The
dependencies
among
the
different
IDL
files
are
shown
in
Figure
5-3




DAISAESession
DAISAESubscription
DAISAEIO
DAISAESource
Condition
DAISConditionSpace
DAISAEReason
DAISAESource
DAISAEArea
DAISServer

from
Server

DAISSession

from
Com
m
on

DAISProperty

from
Common

DAISNode

from
Common

DAISCommon

from
Common

DAISAECommon
DAISType

from
Com
m
on


Figure
5-3
Dependencies
between
alarms
and
events
IDL
files


















File

DAISAECommon
idl
#ifndef

DAIS
AECOMMON
IDL
#define

DAIS
AECOMMON
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{

typedef
ResourceID
EventID


struct
ResourceError

{
Error
err

ResourceID
id


string
reason

}

typedef
sequence<ResourceError>
ResourceErrors





error
codesconst
Error
RES
ERROR
DAISOK=
0
const
Error


RES
ERROR
UNKOWN
RESOURCE=
1

typedef
unsigned
longSourceConditionOpState
const
SourceConditionOpStateCONDITION
ENABLED=
0x0001
const
SourceConditionOpStateCONDITION
ACTIVE=
0x0002
const
SourceConditionOpStateCONDITION
ACKED=
0x0004

typedef
unsigned
short
EventFormat
const
EventFormat
OPC
SIMPLE
EVENT
=
0x0001
const
EventFormat
OPC
TRACKING
EVENT
=
0x0002
const
EventFormat
OPC
CONDITION
EVENT=
0x0004
const
EventFormat
OPC
ALL
EVENTS
=
0x0007
}
}
#endif




DAIS
AECOMMON
IDL
EventID
A
ResourceID
uniquely
identifying
an
event
notification


ResourceError

A
struct
for
reporting
of
resource
related
errors




Member

Description



err

An
error
code
as
described
below




id

The
identification
of
the
resource




reason

An
additional
text
explaining
the
error




ResourceErrors

ResourceErrors
is
a
sequence
containing
errors

If
no
errors
are
present

no
entry
shall
be
included
in
the
sequence
rather
than
including
a
large
number
of
no
errors

An
empty
sequence
means
no
errors


Error

The
error
codes
for
ResourceError




Member

Description



RES
ERROR
DAISOK

No
error




RES
ERROR
UNKOWN
RESOURCE

The
resource
was
not
found




SourceConditionOpState

Flag
word
holding
for
the
operational
state
of
a
SourceCondition

The
definitions
of
the
state
variable
in
the
flag
word
are
listed
below




Flag

Description



CONDITION
ENABLED

The
Condition
is
enabled
and
supervision
is
active




CONDITION
ACTIVE

The
Condition
is
active

that
is

the
supervision
has
determined
that
a
fault
has
activated
the
condition




CONDITION
ACKED

The
Condition
alarm
has
been
acknowledged




The
combinations
of
the
state
variables
result
in
eight
states

The
valid
SourceCondition
operational
states
are
listed
below




State

Description



Disabled

Not
supervised
by
server




Enabled

Inactive

Acked

Supervised
by
server

no
fault
detected
and
all
alarms
are
acknowledged




Enabled

Inactive

Unacked

Supervised
by
server

no
fault
detected
and
unacknowledged
alarms
exist




Enabled

Active

Unacked

Supervised
by
server

a
fault
is
detected
and
unacknowledged
alarms
exist




Enabled

Active

Acked

Supervised
by
server

a
fault
is
persistent
and
all
alarms
are
acknowledged




When
enabled
the
state
{Enabled

Inactive

Acked}
is
entered
and
from
there
the
supervision
will
generate
the
appropriate
state
depending
on
the
result
of
the
supervision

Each
state
change
results
in
sending
an
alarm
and
event
notification

All
notifications
contain
the
state


EventFormat

This
constant
tells
the
format
of
an
event




Member

Description



OPC
SIMPLE
EVENT

The
event
is
a
simple
event




OPC
TRACKING
EVENT

The
event
is
a
tracking
event




OPC
CONDITION
EVENT

The
event
is
a
condition
event




OPC
ALL
EVENTS

This
constant
value
is
used
to
ask
for
all
event
formats
in
a
subscription
set
up




















The
DAIS

AlarmsAndEvents

Session
object
implements
the
alarms
&
events
service
on
a
per
client
basis

An
alarm
&
event
session
object
has
a
number
of
services
provided
by
one
singleton
home
object
each

Each
home
object
provides
methods
for
manipulation
of
the
data
of
the
specific
type
they
provide


The
session
object
corresponds
to
an
OPCEventServer
object




DAIS

ShutdownCallback

from
DAISSessi
on

<<Interface>>



DAIS

AlarmsAndEvents

Session
<<Interface>>
subscription
home




DAIS

AlarmsAndEnvents

Subscription

Home
area
home




DAIS

AlarmsAndEvents

Area

IHome
source
home




DAIS

AlarmsAndEvents

Source

IHome
condition
space
home




DAIS

AlarmsAndEnvents

ConditionSpace

Home
source
condition
home




DAIS

AlarmsAndEvents

SourceCondition

IHome
reason
home




DAIS

AlarmsAndEvents

Category

IHome
type
home




DAIS

Type

IHome
property
home




DAIS

Property

IHome
DAIS

Session

from
DAISSessi
on

<<Interface>>
status




DAIS

SessionStatus
1
01callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy




10

1


0

10

1



11



Client

f
rom
DA
ISServ
er




11



DAIS

AlarmsAndEvents

Area

IHome

from
DAISAEArea

<<Interface>>



0

0
*
*



11



DAIS

AlarmsAndEvents

IO

Callback

f
ro
m
DAISAE
I
O

<<Interface>>



11



DAIS

AlarmsAndEvents

Source

IHome

f
rom
DA
ISAE
Sourc
e

<<Interface>>



0

0
1
1



11



11



DAIS

AlarmsAndEvents

ConditionSpace

IHome

from
DAISAECondi
ti
onSpace


<<Interface>>
DAIS

AlarmsAndEvents

SourceCondition

IHome

f
ro
m
DA
ISAE
Sourc
eConditi
on

<<Interface>>



DAIS

AlarmsAndEvents

Category

IHome

from
DAISAECategory

<<Interface>>
DAIS

AlarmsAndEvents

Subscription

IHome

from
DAISAESu
bscriptio
n

<<Interface>>



11



11



11



11
0


0

n



DAIS

AlarmsAndEvents

Subscription

Manager

fro
m
DAISAESubsc
ri
pti
on

<<Interface>>



11



DAIS

Property

IHome

from
DAISProperty

<<Interface>>

Figure
5-4
DAIS
alarms
and
events
session
IDL
in
UML














File

DAISAESession
idl
#ifndef

DAIS
AESERVER
IDL
#define

DAIS
AESERVER
IDL
#pragma
prefix
"omg
org"




Common
Information#include
<DAISType
idl>#include
<DAISProperty
idl>#include
<DAISSession
idl>



Events
and
Alarms#include
<DAISAESubscription
idl>#include
<DAISAEArea
idl>#include
<DAISAESource
idl>#include
<DAISAEConditionSpace
idl>#include
<DAISAESourceCondition
idl>#include
<DAISAECategory
idl>#include
<DAISAEIO
idl>
module
DAIS
{module
AlarmsAndEvents
{
interface
Session


DAIS

Session
{
readonly
attribute
Subscription

IHome
subscription
home


readonly
attribute
Area

IHome
area
home


readonly
attribute
Source

IHome
source
home


readonly
attribute
ConditionSpace

IHome
condition
space
home


readonly
attribute
SourceCondition

IHome
source
condition
home


readonly
attribute
Category

IHome
category
home


readonly
attribute
Type

IHome
type
home


readonly
attribute
Property

IHome
property
home

}
}
}

#endif




DAIS
AESESSION
IDL


Session

Session
is
an
object
implementing
the
alarms
&
events
functions

It
inherits
common
functionality
as
shut
down
callbacks
and
session
status
from
DAIS

AlarmsAndEvents

Session


subscription
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Subscription

IHome
object


area
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Area

IHome
object


source
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Source

IHome
object


condition
space
home

A
read
only
attribute
holding
a
reference
to
a
singleton
ConditionSpace

IHome
object


source
condition
home

A
read
only
attribute
holding
a
reference
to
a
singleton
SourceCondition

IHome
object


category
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Category

IHome
object


type
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Type

IHome
object


property
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Property

IHome
object


















A
DAIS

AlarmsAndEvents

Subscription

Manager
is
an
object
holding
a
filter
specification
set
up
by
a
client

The
filter
is
used
to
specify
what
notifications
shall
be
sent
to
the
client

A
server
can
support
various
filter
functions
and
a
client
can
ask
the
DAIS

AlarmsAndEvents

Subscription

IHome
object
what
filter
functions
are
supported

The
subscription
home
is
also
used
to
create
any
number
of
subscription
manager
objects

Each
subscription
manager
shall
be
associated
with
a
client
implemented
callback
object
so
that
the
server
can
send
alarm
and
event
notifications
to
the
client


A
server
may
optionally
support
an
event
history

The
event
history
shall
record
all
alarms
and
events
appearing
in
a
server

The
method
async
read
history


gives
clients
access
to
the
event
history

The
size
of
the
event
history
is
server
specific
and
outside
the
control
of
a
client


In
OPC
the
Subscription
interface
corresponds
to
the
interface
IOPCEventSubscription




DAIS

AlarmsAndEvents

Subscription

IHome
query
available
filters


create
subscription


<<Interface>>



0

0
1
1



11






DAIS

AlarmsAndEvents

IO

Callback

from
DAISAEIO

<<Interface>>



0

n0

n



11



DAIS

AlarmsAndEvents

Subscription

Manager
callback




DAIS

AlarmsAndEvents

IO

Callback
callback
in
callback


DAIS

AlarmsAndEvents

IO

Callback

set
filter


get
filter


select
returned
properties


get
returned
properties


refresh


asynch
read
history


cancel


get
state


set
state


clone


destroy


<<Interface>>



11


0

0
n
n



PropertySelection
category


ResourceID
properties


PropertyIDs



11






11



11



DAIS

AlarmsAndEvents

Subscription

FilterSpec
reason
filter


ReasonFilter
low
severity


unsigned
long
high
severity


unsigned
long
source
filter


SourceFilter
type
filter


TypeIDs
DAIS

AlarmsAndEvents

Subscription

State
active


boolean
buffer
time


unsigned
long
max
size


unsigned
long
keep
alive
time


unsigned
long
11
Figure
5-5
DAIS
alarms
and
events
subscription
IDL
in
UML











File

DAISAESubscription
idl
#ifndef

DAIS
AESUBSCRIPTION
IDL
#define

DAIS
AESUBSCRIPTION
IDL
#pragma
prefix
"omg
org"
#include
<DAISAEIO
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Subscription
{

struct
State
{
boolean
active

unsigned
long
buffer
time

unsigned
long
max
size

unsigned
long
keep
alive
time


}


struct
OPCSourceFilter
{
ServerItemIdentifications
areas

ServerItemIdentifications
sources


}

typedef
short
SourceFilterType
const
SourceFilterType
OPC
SOURCE
FILTER
TYPE
=
1
const
SourceFilterType
XPATH
SOURCE
FILTER
TYPE
=
2

union
SourceFilter
switch
SourceFilterType

{
case
OPC
SOURCE
FILTER
TYPE



OPCSourceFilter
opc
source
filters

case
XPATH
SOURCE
FILTER
TYPE


string
xpath
source
filter

}


typedef
short
CategoryFilterType
const
CategoryFilterType
OPC
REASON
FILTER
TYPE
=
1
const
CategoryFilterType
XPATH
REASON
FILTER
TYPE=
2

union
CategoryFilter
switch
ReasonFilterType

{
case
OPC
CATEGORY
FILTER
TYPE


ServerItemIdentifications
opc
category
filters

case
XPATH
CATEGORY
FILTER
TYPE


string
xpath
category
filter

}


struct
FilterSpec
{
EventFormat
event
format

CategoryFilter
category
filter

unsigned
long
low
severity

unsigned
long
high
severity


SourceFilter
source
filter

ResourceIDs
type
filter

}


struct
PropSelection
{
ResourceID
category

PropertyIDs
properties


}
typedef
sequence<PropSelection>
PropSelections

enum
ReadDirection
{
READ
FORWARDS

READ
BAKWARDS

}


typedef
unsigned
long
CancelID


interface
Manager

{
exception
BusyDueToRefresh{string
reason
}

exception
HistoryNotImplemented{string
reason
}


attribute
IO

Callback
callback


void
set
filter

in
FilterSpec
filer
spec

raises

BusyDueToRefresh


FilterSpec
get
filter





void
select
returned
properties

in
PropSelections
prop
selections


PropSelections
get
returned
properties

in
ResourceIDs
categories


CancelID
refresh



raises

BusyDueToRefresh



CancelID
async
read
history


in
DateTime
start
time

in
unsigned
long
number
of
events

in
ReadDirection
direction

in
unsigned
long
transaction
id



raises

HistoryNotImplemented



void
cancel

in
CancelID
cancel
id


void
refresh



raises

BusyDueToRefresh



void
refresh
with
history

in
DateTime
start
time
in
DateTime
end
time


raises

HistoryNotImplemented



void
cancel
refresh





State
get
state





State

set
state


in
State
subscription
spec

Manager
clone





void
destroy




}


typedef
unsigned
longFilter
const
Filter
FILTER
BY
EVENT
FORMAT
=
0x0001
const
Filter
FILTER
BY
CATEGORY
=
0x0002
const
Filter
FILTER
BY
SEVERITY
=
0x0004
const
Filter
FILTER
BY
AREA
=
0x0008
const
Filter
FILTER
BY
SOURCE
=
0x0010
const
Filter
FILTER
WITH
XPATH
=
0x0020
const
Filter
FILTER
BY
SOURCE
TYPE
=
0x0040

interface
IHome{
Filter
query
available
filters





Manager
create
subscription


in
State
subscription
spec

out
State

revised
subscr
spec



}
}
}
}

#endif




DAIS
AESUBSCRIPTION
IDL

State
A
struct
describing
the
state
for
the
subscription




Member

Description



active

Indicates
if
the
subscription
is
active

that
is

is
sending
data
on
the
call
back
interface

Events
that
are
appearing
in
the
server
will
be
lost
for
clients
connected
to
inactive
subscriptions




buffer
time

The
requested
buffer
time
in
milliseconds

This
is
a
minimum
time
-
do
not
send
event
notifications
any
faster
that
this
UNLESS
max
size
is
greater
than
0

in
which
case
the
server
will
send
an
event
notification
sooner
to
obey
the
max
size
value

A
value
of
0
for
buffer
time
means
that
the
server
should
send
event
notifications
as
soon
as
it
gets
them


This
parameter
along
with
the
max
size
parameter
is
used
to
improve
communications
efficiency
between
client
and
server

This
parameter
is
a
recommendation
from
the
client

and
the
server
is
allowed
to
ignore
the
parameter

The
server
will
return
the
buffer
time
it
is
actually
providing
in
revised
buffer
time




max
size
The
requested
maximum
number
of
events
that
will
be
sent
in
a
single
callback

A
value
of
0
means
that
there
is
no
limit
to
the
number
of
events
that
will
be
sent
in
a
single
callback

Note
that
a
value
of
max
size
greater
than
0

may
cause
the
server
to
make
callbacks
more
frequently
than
specified
by
buffer
time
when
a
large
number
of
events
are
being
generated
in
order
to
limit
the
number
of
events
to
the
max
size

This
parameter
is
a
recommendation
from
the
client
and
the
server
is
allowed
to
ignore
this
parameter

The
server
will
return
the
actual
number
of
events
it
is
actually
providing
in
revised
max
size


keep
alive
time
The
time
in
milliseconds
for
the
server
to
send
a
callback
to
client

The
intention
is
to
indicate
to
the
client
that
the
server
is
alive
and
avoid
the
need
to
"poll"
the
server
to
check
it
is
alive

If
no
data
is
available
an
empty
message
is
sent

If
the
time
is
less
than
the
buffer
time
the
buffer
time
is
used


OPCSourceFilter

The
struct
specifies
source
filtering
by
enumerating
the
areas
and
sources
the
way
OPC
does
it




Member

Description



areas

A
sequence
of
ResourceIDs
for
the
areas
that
shall
be
notified

All
sources
below
an
area
node
will
be
notified




sources

A
sequence
of
ResourceIDs
for
sources
that
shall
be
notified

An
empty
sequence
means
all
sources
shall
be
notified




SourceFilter

The
union
specifies
OPCSourceFiltering
or
XPath
filtering

A
prerequisite
for
XPath
filtering
is
that
the
area
and
source
hierarchy
has
an
XML
mapping

The
same
mapping

is
used
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?
on

page
3-25
with
the
additional
comments





•

an
Area
corresponds
to
a
Node

Area
inherits
Node





•

a
Source
corresponds
to
a
Node

Source
inherits
Node







Member

Description



opc
source
filters

An
OPCSourceFilter



xpath
source
filter

An
XPath
filter




CategoryFilter

The
union
specifies
OPC
style
filtering
or
XPath
filtering
of
categories

A
prerequisite
for
XPath
filtering
is
that
the
resource
hierarchy
has
an
XML
mapping

The
same

mapping
is
used
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?

on
page
3-25
with
the
additional
comments



•
a
Resource
corresponds
to
a
Node

Resource
inherits
Node





Member

Description



opc
category
filters

An
OPCSourceFilter



xpath
reason
filter

An
XPath
filter



FilterSpec

A
struct
holding
the
specification
for
how
the
server
shall
filter
notifications
sent
to
the
client

The
struct
is
used
to
specify
the
filtering
a
client
wants
a
server
to
do
for
it

All
specified
filter
criterias
shall
be
fulfilled
for
a
notification
to
be
sent




Member

Description



event
format

An
EventFormat
bit
mask
specifying
the
event
formats
to
be
returned




reasons

A
sequence
of
CategoryFilter
for
the
categories
for
which
the
client
wants
to
get
notifications

Observe
that
specifying
a
main
category

for
example

Simple

Tracking

Condition

will
result
in
notifications
for
all
sub-categories
specified
for
that
main
category




low
severity

The
client
wants
all
events
with
greater
or
equal
severity




high
severity

The
client
wants
all
events
with
less
or
equal
severity




sources

A
SourceFilter
for
the
sources
that
shall
be
notified




types

A
sequence
of
TypeIDs
for
the
types
that
shall
be
notified




PropSelection

A
struct
identifying
what
properties
shall
be
included
in
an
event
notification
for
a
specific
reason




Member

Description



reason

The
reason
for
which
the
property
selection
is
made




properties

A
sequence
of
PropertyIDs
for
the
selected
properties




ReadDirection

An
enumeration
that
tells
if
a
read
of
history
shall
be
forward
or
backwards
in
time




Member

Description



READ
FORWARDS

Read
events
after
the
given
start
time




READ
BAKWARDS

Read
events
before
the
given
start
time




Manager

An
object
managing
subscription
and
filtering
of
event
notifications
per
client


BusyDueToRefresh

An
exception
stating
that
a
refresh
is
already
going
on


HistoryNotImplemented

An
exception
stating
that
the
server
does
not
record
the
event
history


callback

An
attribute
holding
a
reference
to
the
callback
object

The
client
is
required
to
update
the
attribute
with
a
by
the
client
implemented
callback
object
to
get
event
notifications
from
the
server

The
attribute
corresponds
to
the
IConnectionPoint
interface
in
OPC


set
filter



The
method
updates
the
filter
specification

A
try
to
change
the
filter
spec
during
an
ongoing
refresh
will
give
an
exception

The
method
corresponds
to
IOPCEventSubscriptionMgt

SetFilter






Member

Description



filer
spec

The
filter
specification




return

none




get
filter



The
method
gets
the
filter
specification

The
method
corresponds
to
IOPCEventSubscriptionMgt

GetFilter






Member
Description
return
The
filter
specification


select
returned
properties



The
method
sets
what
properties
shall
be
included
in
a
notification
specified
per
reason

The
method
corresponds
to
IOPCEventSubscriptionMgt

SelectReturnedAttributes






Member

Description



prop
selections

A
sequence
specifying
what
properties
to
include
per
reason




return

none




get
returned
properties



The
method
gets
what
properties
currently
are
included
in
a
notification
specified
per
category

The
method
corresponds
to
IOPCEventSubscriptionMgt

GetReturnedAttributes






Member

Description



categories

The
categories
for
that
shall
be
used
to
fetch
the
properties




return

A
sequence
specifying
what
properties
currently
are
included
per
reason




refresh



The
method
forces
notifications
for
all
currently
active
source
conditions

The
notifications
will
not
include
the
history
but
only
the
current
source
condition
operational
state

The
method
corresponds
to
IOPCEventSubscriptionMgt

Refresh






Member
Description
return
A
server
generated
handle
that
the
client
can
use
to
cancel
the
operation


async
read
history



The
method
read
historic
events
recorded
by
the
server

If
the
server
does
not
support
recording
of
alarms
and
events
an
exception
is
raised

No
corresponding
method
exists
in
OPC




Member

Description



start
time

The
time
where
to
start
the
read

An
unspecified
time

=0

will
make
the
read
start
from
the
oldest
recorded
event




number
of
events

The
max
number
of
events
to
deliver
as
a
response
to
the
read
operation






Member

Description



direction

Tells
if
events
before
or
after
the
start
time
shall
be
read




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
server
generated
handle
that
the
client
can
use
to
cancel
the
operation




cancel



The
method
cancels
an
ongoing
refresh
operation
or
async
read
history


operations

It
corresponds
to
IOPCEventSubscriptionMgt

CancelRefresh






Member

Description



cancel
id

A
server
generated
handle
that
is
given
back
to
the
server
when
a
started
operation
shall
be
cancelled




return

none




get
state



The
method
gets
the
current
subscription
state
and
corresponds
to
IOPCEventSubscriptionMgt

GetState






Member
Description
return
The
current
subscription
state


set
state



The
method
sets
the
current
subscription
state
and
corresponds
to
IOPCEventSubscriptionMgt

SetState



The
actual
parameters
set
are
returned
and
an
exception
is
raised
if
any
input
parameters
are
not
accepted
and
hence
changed




Member

Description



subscription
spec

New
state
wanted
for
the
subscription




return

The
accepted
subscription
state




clone



The
method
creates
a
copy
of
the
subscription


5-22
Data
Acquisition
from
Industrial
Systems

v1
1
June
2005



Member
Description
return
The
copied
subscription


destroy



The
method
destroys
the
subscription
object


Filter

A
flag
word
holding
flags
specifying
the
filters
that
are
implemented
by
the
server




Flag

Description



FILTER
BY
MAIN
CATEGORY

Filtering
by
main
category
is
supported




FILTER
BY
CATEGORY

Filtering
by
sub-category
is
supported




FILTER
BY
SEVERITY

Filtering
by
severity
is
supported




FILTER
BY
AREA

Filtering
by
area
is
supported




FILTER
BY
SOURCE

Filtering
by
source
is
supported




FILTER
WITH
XPATH

XPath
as
filter
description
is
supported




FILTER
BY
SOURCE
TYPE

Filtering
by
source
type
is
supported




IHome

A
factory
object
for
creation
of
subscription
management
objects


query
available
filters



Gets
by
the
server
implemented
filter
functions

The
method
corresponds
to
IOPCEventServer

QuearyAvailableFilters






Member
Description
return
Filter
specification
flagword


create
subscription



Creates
a
subscription
management
object

An
invalid
state
will
give
an
exception




Member
Description
subscription
spec
State
wanted
for
the
subscription




revised
subscr
spec
State
accepted
by
the
server

return
The
new
subscription
manager

Set
up
Subscription

query
available
filters








Client
Client


DAIS

AlarmsAndEvents

Subscription

IHome
DAIS

AlarmsAndEvents

Subscription

IHome


DAIS

AlarmsAndEvents

Subscription

Manager
DAIS

AlarmsAndEvents

Subscription

ManagerCheck
what
filters
are
supported
by
the
server
create
subscription



callback
DAISCallback

select
returned
properties



Set
the
callback
for
server
to
use
set
filter



Set
up
filter
to
get
only
wanted
event
notifications
Select
what
property
values
to
be
included
in
event
notifications
Do
some
browsing
to
prepare
for
setting
up
the
filter

Browse
for
reasons

areas
and
sources
Do
some
browsing
to
prepare
for
selecting
properties

Figure
5-6
Set
up
subscription
interaction

Refresh





Client

Client


DAIS

AlarmsAndEvents

Subscription

Manager

DAIS

AlarmsAndEvents
backbac
Subscription

Manager


DAIS

AlarmsAndEvents

IO

Call

DAIS

AlarmsAndEvents

IO

Callkrefresh



Initiate
transfer
of
the
currently
active
source
conditions
on
event



on
event



on
event



As
many
notifications
sent
as
needed
to
report
all
source
conditions

Figure
5-7
Refresh
interaction

















An
area
is
a
specialization
of
a
node
and
is
a
collection
of
other
areas
or
sources

Areas
are
intended
for
arbitrary
hierarchical
structuring
of
sources
for
various
usages

for
example

areas
for
authority
or
responsibility



DAIS

AlarmsAndEvents

Area

IHome
is
used
for
browsing
the
area
hierarchy

The
find
methods
in
the
interface
correspond
to
the
IOPCEventAreaBrowser
with
the
filter
type
parameter
set
to
OPC
AREA

The
interface
also
implements
the
following
OPC
methods




•

IOPCEventServer

EnableConditionByArea





•

IOPCEventServer

DisableConditionByArea







DAIS

AlarmsAndEvents

Area

IHome
<<Interface>>
get
root


enable
condition


disable
condition


DAIS

Node

IHome

from
DAISNode

<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids





AreaSourceComponent
id


ResourceID
name


string
description


string
Area
Source

from
DAISAESource

11


0

0
n
n


0

0
n
n

+parent




Figure
5-8
DAIS
alarms
and
events
area
IDL
in
UML











File

DAISAEArea
idl
#ifndef

DAIS
AEAREA
IDL
#define

DAIS
AEAREA
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Area
{

interface
IHome


Node

IHome
{
ResourceID
get
root




ResourceErrors
enable
condition


in
ResourceIDs
areas




ResourceErrors
disable
condition



in
ResourceIDs
areas





}


}
}
}


#endif




DAIS
AEAREA
IDL

IHome

An
object
for
browsing
areas


get
root



A
method
to
get
the
root
node
for
the
area
tree




Member
Description
return
The
root
area
node


enable
condition



A
method
for
enabling
the
sources
contained
by
the
specified
areas

The
corresponding
OPC
method
is
IOPCEventServer

EnableConditionByArea






Member

Description



areas

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




disable
condition



A
method
for
disabling
the
sources
contained
by
the
specified
areas

The
corresponding
OPC
method
is
IOPCEventServer

DisableConditionByArea






Member

Description



areas

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




Browse
areas

get
root








Client

Client


DAIS

AlarmsAndEvents

Area

IHome

DAIS

AlarmsAndEvents

Area

IHome


DAIS

Node

Iterator
DAIS

Node

IteratorGet
the
root
of
all
areas
find
by
parent



next
n



Repeat
find
by
parent
and
next
n
until
the
areas
are
explored

Figure
5-9
Browse
areas
interaction

















A
source
is
a
specialization
of
a
node
and
is
contained
by
areas

A
source
represents
an
object
that
generates
alarms
and
events

A
source
may
have
source
conditions

The
find
methods
in
the
interface
correspond
to
the
IOPCEventAreaBrowser
with
the
filter
type
parameter
set
to
OPC
SOURCE

The
interface
also
implements
the
following
OPC
methods




•

IOPCEventServer

TranslateToItemIDs



•

IOPCEventServer

EnableConditionBySource





•

IOPCEventServer

DisableConditionBySource






DAIS

Node

IHome

from
DAISNode

<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids


DAIS

AlarmsAndEvents

Source

IHome
<<Interface>>
translate
to
item
ids


enable
conditions


disable
conditions


Source
0

n
1
0

n10

n
1
0

n1Area

from
DAI
SAEArea

AreaSourceComponent

from
DAI
SAEArea

id


ResourceID
name


string
description


string
0

n
+parent
0

n


SourceCondition

from
DAISAESo
urceCon
di
tion

condition
op
state


DAISConditionOpState
quality


DAIS

Quality
last
acknowledge


DateTime
condition
last
active


DateTime
condition
space
last
active


DateTime
condition
space
last
inactive


DateTime
acknowledger
name


string
comment


string

Figure
5-10
DAIS
alarms
and
events
source
IDL
in
UML











File

DAISAESource
idl
#ifndef


DAIS
AESOURCE
IDL
#define


DAIS
AESOURCE
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Source
{

interface
IHome


Node

IHome
{
exception
PropertyDidNotTranslate{string
reason
}


ItemIDs
translate
to
item
ids

in
ResourceID
source
in
ResourceID
category
in
PropertyIDs
properties


raises

PropertyDidNotTranslate



ResourceErrors
enable
conditions

in
ResourceIDs
sources


ResourceErrors
disable
conditions

in
ResourceIDs
sources



}
}
}
}

#endif





DAIS
AESOURCE
IDL

IHome

An
object
for
browsing
sources
at
areas


PropertyDidNotTranslate

An
exception
telling
that
one
or
more
properties
did
not
translate
to
ItemIDs


translate
to
item
ids



A
method
for
translation
of
information
about
a
source
to
ItemIDs
for
use
with
the
data
access
interface

If
one
or
more
properties
did
not
translate
to
ItemIDs

an
exception
is
raised

The
corresponding
OPC
method
is
IOPCEventServer

TranslateToItemIDs






Member

Description



source

The
identification
of
the
source




category

The
identification
of
the
category




properties

A
sequence
of
properties
for
which
ItemIDs
are
wanted




return

A
sequence
of
ItemIDs

Properties
that
did
not
translate
to
ItemIDs
are
returned
as
empty
ItemIDs




enable
conditions



A
method
for
enabling
the
specified
sources

The
corresponding
OPC
method
is
IOPCEventServer

EnableConditionBySource






Member

Description



sources

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




disable
conditions



A
method
for
disabling
specified
sources

The
corresponding
OPC
method
is
IOPCEventServer

DisableConditionBySource






Member

Description



sources

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed



Browse
sources





Client

Client


DAIS

AlarmsAndEvents

Source

IHome

DAIS

AlarmsAndEvents

Source

IHome


DAIS

Node

Iterator
DAIS

Node

Iteratorfind
by
parent



Get
all
sources
that
has
a
given
area
as
parent
next
n



Repeat
getting
all
found
sources
from
the
iterator
and
continue
with
another
area
as
parent
to
sources

Repeat
this
until
all
wanted
sources
are
explored

For
each
source
inspect
the
conditions
it
might
have

refer
to
ConditionSpace

Figure
5-11
Browse
sources
interaction

















A
condition
space
describes
a
set
of
conditions

that
is

it
is
a
space
of
conditions

Each
condition
space
is
associated
with
a
particular
sub-reason
of
the
main
reason
ConditionReason

Each
condition
has
logic
describing
when
the
condition
is
active

The
logic
is
described
in
a
little
language
having
the
following
constructs




•

arithmetic
operators



•

logic
operators



•

references
to
properties



The
referred
properties
must
be
included
in
the
set
of
properties
defined
by
the
associated
reason

The
little
language
grammar
is
server
specific
and
is
outside
the
scope
of
this
specification

Transitions
describe
what
transitions
between
conditions
are
allowed

The
interface
does
not
support
exploration
of
the
transitions


In
OPC
the
ConditionSpace
interface
is
implemented
by
the
methods




•

IOPCEventServer

QueryConditionNames





•

IOPCEventServer

QuerySubConditionNames










DAIS

AlarmsAndEvents

ConditionSpace

IHome
<<Interface>>
find


find
each


find
by
reason


find
by
source


get
names


get
ids


11


0

0
n
n



1

1
n
n


11



ConditionSpace
id


ResourceID
name


string
description


string
Condition
id
number


unsigned
long
name


string
description


string
severity


unsigned
long
condition
logic


string



ConditionCategory

from
DAISAECategory




1

1
n
n

+conditions



0

0
n
n



0

n0

n



Transition



11


11


0

0
n
n




ConditionEvent


from
DAISAEIO


Figure
5-12
DAIS
alarms
and
events
condition
space
IDL
in
UML











File

DAISAEConditionSpace
idl
#ifndef

DAIS
AECONDITION
SPACE
IDL
#define

DAIS
AECONDITION
SPACE
IDL
#pragma
prefix
"omg
org"
#include
<DAISAECommon
idl>

module
DAIS
{module
AlarmsAndEvents
{module
ConditionSpace
{
struct
ConditionDescription
{




unsigned
long

id
number





string

name





string

condition
logic





unsigned
long

severity





string

descrip




}






typedef
sequence<ConditionDescription>
ConditionDescriptions


struct
Description

{

ResourceID
id


string
name


string
descrip


ConditionDescriptionsconditions

}

typedef
sequence<
Description
>Descriptions


interface
IHome
{

exception
UnknownResourceID
{string
reason
}


Description
find


in
ResourceID
condition
space


raises

UnknownResourceID



Descriptions
find
each


in
ResourceIDs
condition
spaces


raises

UnknownResourceID



Descriptions
find
by
category


in
ResourceID
category


raises

UnknownResourceID



Descriptions
find
by
source


in
ResourceID
source


raises

UnknownResourceID



Strings
get
names


in
ResourceIDs
condition
spaces




ResourceIDs
get
ids


in
Strings
names




}
}
}
}
#endif




DAIS
AECONDITION
SPACE
IDL
ConditionDescription

A
struct
describing
a
condition




Member

Description



id
number

A
numeric
identification
unique
within
the
condition
space




name

The
name
of
the
condition




condition
logic


The
logic
telling
when
the
condition
is
active

Refer
to
Section
5
2
7
3

“Condition
Logic
?
on
page
5-38
for
a
description





severity

Severity
is
a
number
between
1
and
1000
having
the
following
meaning

•
Low
severity
1-200
•
Medium
low
severity
201-400
•
Medium
severity
401-600
•
Medium
high
severity
601-800
•
High
severity
801-1000



description

A
text
that
to
be
included
in
event
notifications
when
the
condition
is
active




Description

A
struct
describing
the
condition
space




Member

Description



id

A
ResourceID
identifying
the
condition
space




name

The
name
of
the
condition
space




description

A
description
of
the
condition
space




conditions

A
sequence
of
the
conditions
creates
the
condition
space

In
OPC
the
conditions
are
called
sub-conditions
and
are
retrieved
by
the
method
IOPCEventServer

QuerySubConditionNames






IHome

An
object
for
browsing
the
condition
spaces
defined
by
a
server


find



A
method
for
getting
the
description
of
a
condition
space




Parameter

Description



condition
space

A
ResourceID
identifying
a
condition
space




return

The
condition
space
description




find
each



A
method
for
getting
the
descriptions
for
a
number
of
condition
spaces




Parameter

Description



condition
spaces

A
sequence
of
ResourceID
identifying
condition
spaces




return

A
sequence
of
condition
space
descriptions




find
by
category



A
method
for
finding
all
condition
spaces
defined
for
a
category

The
corresponding
OPC
method
is
IOPCEventServer

QueryConditionNames






Parameter

Description



category

A
ResourceID
identifying
the
category
for
which
to
get
the
condition
spaces




return

A
sequence
of
condition
space
descriptions




find
by
source



A
method
for
finding
all
condition
spaces
defined
for
a
source

The
corresponding
OPC
method
is
IOPCEventServer

QuerySourceConditions






Parameter

Description



source

A
ResourceID
identifying
the
source
for
which
to
get
the
condition
spaces




return

A
sequence
of
condition
space
descriptions




get
names



A
method
translating
a
number
of
condition
space
identifications
into
name
strings




Parameter

Description



condition
spaces

A
sequence
of
ResourceID
identifying
condition
spaces




return

A
sequence
of
condition
space
names

Non-translated
identifications
are
returned
as
empty
strings




get
ids



A
method
translating
a
number
of
condition
space
names
into
ResourceIDs




Parameter

Description



names

A
sequence
of
condition
space
names




return

A
sequence
of
condition
space
ResourceIDs

Non-
translated
identifications
are
returned
as
NULL
IDs



Browse
condition
space
by
source





Client

Client


DAIS

AlarmsAndEvents

ConditionSpace

IHome

DAIS

AlarmsAndEvents

ConditionSpace

IHomefind
by
source



Get
all
condition
space
descriptions
for
one
source

Explore
each
condition
space
from
the
retrieved
descriptions

Figure
5-13
Browse
condition
space
by
source
interaction

Browse
condition
space
by
category





Client

CliAlrmsAndEvents

ConditionSpace

IHomeAent


DAIS

a

DAIS

larmsAndEvents

ConditionSpace

IHome
find
by
category






Get
all
condition
space
description
for
one
category

Explore
each
condition
space
from
the
retrieved
descriptions


Figure
5-14
Browse
condition
space
by
category
interaction








The
reduced
XPath
language
as
defined
in
Section
3
1
12

“Logical
Expressions
and

Navigation
?
on
page
3-25
is
used
to
describe
the
condition
logic

This
allows

description
of
a
path
through
a
data
structure
picking
up
property
values
to
be
used
in
a
logical
expression


A
common
case
is
property
values
at
objects
associated
with
a
source

hence
the
starting
point
for
navigation
is
the
source

An
example
from
the
CIM
model
where
the

Measurement
is
the
source
can
be
found
in
Figure
4-3
on
page
4-6



Examples
how
to
use
DAIS
Expressions
starting
from
a
source
are
shown
below


Measurement
value
<
500
assuming
that
the
tested
value
is
an
element
at
the
source


MeasurementValue[id
MeasurementValue
MeasurementValueSource

label='telemetry']

MeasurementValue
value
<
id
Measurement
LimitSets
[LimitSet
label
=
'summer']
Limit[label
=
'highalarm']
Limit
value


Based
on
the
model
in
Figure
4-3
on
page
4-6

the
XML
example
in
Section
3
1
12


“Logical
Expressions
and
Navigation
?
on
page
3-25
and
the
source
as
a
Measurement





















A
source
condition
associates
a
source
with
a
condition
space

A
source
condition
holds
the
current
information
specific
to
a
source
using
a
particular
condition
space
for
the
supervision

A
source
condition
has
no
own
identification
and
is
identified
by
its
associated
source
and
condition
space

Information
about
a
source
condition
is
accessed
through
its
home
object

In
OPC
a
source
condition
is
sometimes
called
an
instance
of
a
condition


In
OPC
the
SourceCondition
interface
is
implemented
by
the
methods




•

IOPCEventServer

QuerySourceConditions





•

IOPCEventServer

AckCondition











DAIS

AlarmsAndEvents

SourceCondition

IHome
<<Interface>>
find


find
each


ack
condition





Source

from
DAISAE
Source



11


0

0
n
n


11


0

0
n
n



0

0
n
n


11



11



ConditionSpace

from
DAISAE
Condi
ti
onSpace

id


ResourceID
name


string
description


string
Condition

from
DA
ISAECondi
ti
onSpace

id
number


unsigned
long
name


string
description


string
severity


unsigned
long
condition
logic


string
SourceCondition
condition
op
state


DAISConditionOpState
quality


DAIS

Quality
last
acknowledge


DateTime
condition
last
active


DateTime
condition
space
last
active


DateTime
condition
space
last
inactive


DateTime
acknowledger
name


string
comment


string
0

0
n
+active
condition

n
Figure
5-15
DAIS
alarms
and
events
source
condition
IDL
in
UML











File

DAISAESourceCondition
idl
#ifndef

DAIS
AESOURCE
CONDITION
IDL
#define

DAIS
AESOURCE
CONDITION
IDL
#pragma
prefix
"omg
org"
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
SourceCondition
{

struct
Id
{




ResourceID

source





ResourceID

condition
space




}






typedef
sequence<Id>Ids


struct
Description
{

Id
source
condition
SourceConditionOpState
source
condition
op
state
unsigned
long
active
condition
string
ac
logic
unsigned
long
ac
severity
string
ac
description
Quality
dais
quality
DateTime
last
acknowledge
DateTime
condition
last
active
DateTime
condition
space
last
active
DateTime
condition
space
last
inactive
string
acknowledger
name
string
comment
PropertyValues
property
values

}
typedef
sequence<
Description
>
Descriptions

struct
AcknowledgeSpec
{
Id
source
condition

DateTime
active
time

EventID
cookie


}

typedef
sequence<AcknowledgeSpec>AcknowledgeSpecs


interface
Iterator
{
boolean
next
n






in

unsigned
long

n





out

Descriptions

c
descriptions












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownId
{string
reason
}

exception
UnknownPropertyID
{string
reason
}


Description
find


in
Id
source
condition

in
PropertyIDs
properties



raises

UnknownId

UnknownPropertyID



Iterator
find
each

in
Ids
source
conditions

in
PropertyIDs
properties



raises

UnknownId

UnknownPropertyID



Descriptions
ack
condition


#endif




DAIS
AESOURCE
CONDITION
IDL
Id




in
string

acknowledger
name





in
string

comment





in
AcknowledgeSpecs
ack
spec











}






}
}
}






A
struct
that
identifies
a
source
condition




Member

Description



source

The
ResourceID
identifying
the
associated
source




condition
space

The
ResourceID
identifying
the
associated
condition
space




Description

A
struct
describing
the
source
condition




Member

Description



id

The
Id
identifying
the
source
condition




source
condition
op
state

The
DAISSourceConditionOpState
as
described
in
Section
5
2
2

“Alarms
and
Events
Common
IDL
Definitions
?
on
page
5-7




active
condition

The
identification
number
of
the
currently
active
condition




ac
logic

The
condition
logic
from
the
active
condition




ac
severity

The
severity
from
the
active
condition




ac
description

The
description
from
the
active
condition




dais
quality

The
quality
is
evaluated
from
the
qualities
from
the
properties
used
to
evaluate
the
condition
logic




last
acknowledge

The
last
time
the
condition
was
acknowledged




condition
last
active

Time
for
the
latest
condition
transition






condition
space
last
active

The
last
time
when
the
condition
space
became
active

After
this
time
more
condition
transitions
may
occur

The
condition
last
active
will
then
be
later
than
condition
space
last
active




condition
space
last
inactive

The
last
time
when
the
condition
space
became
inactive

that
is

no
conditions
are
active




acknowledger
name

The
name
of
the
client
making
an
acknowledge




comment

A
comment
passed
by
the
client
making
an
acknowledge




property
values

A
sequence
of
property
values
as
selected
by
the
Manager

select
returned
properties
call




AcknowledgeSpec

A
struct
specifying
an
alarm
to
acknowledge




Member

Description



source
condition

The
Id
identifying
the
source
condition
for
which
to
acknowledge
an
alarm




active
time

The
time
when
the
alarm
activated




cookie

A
identification
of
the
alarm




Iterator

A
standard
iterator

Refer
to
Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10


IHome

An
object
for
browsing
and
accessing
source
conditions


UnknownDAISSourceConditionID

An
exception
telling
that
the
source
condition
identification
was
not
recognized


UnknownPropertyID

An
exception
telling
that
a
property
identification
was
not
recognized


find



A
method
for
getting
the
description
of
a
source
condition

The
corresponding
OPC
method
is
IOPCEventServer

GetConditionState






Parameter

Description



source
condition

A
ResourceID
identifying
a
source
condition




return

The
source
condition
description




find
each



A
method
for
getting
the
descriptions
for
a
number
of
source
conditions




Parameter

Description



condition
spaces

A
sequence
identifying
source
conditions




return

A
sequence
of
source
condition
descriptions




ack
condition



A
method
to
acknowledge
a
number
of
source
condition
alarms

The
corresponding
OPC
method
is
IOPCEventServer

AckCondition






Parameter

Description



acknowledger
name

The
name
of
the
client
making
the
acknowledge




comment

A
comment
to
be
added
to
source
condition
and
the
event




ack
spec

A
sequence
specifying
the
alarms
to
acknowledge




return

A
sequence
containing
descriptions
for
the
acknowledged
source
conditions



Inspect
a
specific
source
condition





Client

Client


D
A
IS



AlarmsA
ndEvent
s

S
ourc
eC
ondition


IH
ome
DAIS

AlarmsAndEvents

SourceCondition

IHomefind



Get
all
det
ails
on
a
s
pec
ific
source
c
ondit
on

Figure
5-16
Inspect
a
specific
source
condition
interaction

Acknowledge
alarm





Client

Client


DAIS

AlarmsAndEvents

SourceCondition

IHom
e
DAIS

AlarmsAndEvents

SourceCondition

IHomeack
condition



Acknolwedge
a
set
of
source
conditions
in
one
call

Figure
5-17
Acknowledge
alarm
interaction











These
are
definitions
for
manipulating
categories

A
category
describes
the
content
of
an
event

Categories
are
organized
in
a
two
level
hierarchy
where
the
first
level
has
the
three
mandatory
main
categories

simple

condition

and
tracking


Simple
category
does
not
have
a
condition
space

refer
to
ConditonSpace


Generation
of
simple
category
alarms
or
events
is
coded
into
some
software
function
and
cannot
be
configured

Typical
simple
categories
are
program
errors

hardware
device
failures

etc


Sources
of
different
types

e
g


breaker
position

breaker
current

generator
active
power

etc


may
have
different
ways
an
alarm
or
event
is
generated

e
g


breaker
trip

breaker
over
current

generator
active
power
generation
overload

etc



Condition
categories
are
used
to
describe
source
type
specific
alarm
and
event
contents


The
alarm
and
event
generation
for
a
condition
category
is
configured
using
condition
spaces
and
several
condition
spaces
can
be
created
for
the
same
condition
category

This
corresponds
to
variations
in
the
way
the
alarms
and
events
are
generated
using
different
condition
logics


Alarms
or
events
due
to
operator
actions
or
control
functions

intended
alarms
or
events
rather
than
spontaneous

use
tracking
categories


A
category
has
a
set
of
properties
associated
with
it

Some
or
all
of
the
properties
may
be
included
in
event
notifications

The
properties
come
from
the
source
type
and
may
be
used
by
the
logic
generating
an
event
notification


The
get
main

category



method
is
used
to
obtain
the
three
main
categories

The
find
by
parent


is
used
to
get
the
child
categories

Categories
at
this
second
level
correspond
to
the
OPC
EventCategories

The
labels
for
the
three
main
reasons
are
“DAIS
CONDITION
CATEGORY
?
“DAIS
TRACKING
CATEGORY
?
and
"DAIS
SIMPLE
CATEGORY
?

In
OPC
the
Category
interface
is
implemented
by
the
methods
IOPCEventServer

QueryEventCategories


and
IOPCEventServer

QueryEventAttributes






TrackingCategory
SimpleCategory
ConditionCategory
DAIS

AlarmsAndEvents

Category

IHome
get
main
categories


get
event
properties


<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids



from
DAISNode

<<Interface>>
Node
id


ResourceID
label


string
type


ResourceID

f
rom
DA
ISNo
de

1
0

10

nCategory

Figure
5-18
DAIS
alarms
and
events
categories
IDL
in
UML












File

DAISAECategory
idl
#ifndef

DAIS
AECATEGORY
IDL
#define

DAIS
AECATEGORY
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>

module
DAIS
{module
AlarmsAndEvents
{module
Category{
interface
IHome


Node

IHome
{
Node

Descriptions
get
main
categories





PropertyIDs
get
event
properties

in
ResourceID
category



}

}
}
}

#endif




DAIS
AECATEGORY
IDL

IHome

IHome
is
an
object
for
browsing
categories

Most
of
the
browsing
functionality
is
inherited
from
DAIS

Node


get
main
categories



Get
the
three
main
categories

simple

condition

and
tracking

The
three
main
categories
appear
as
three
different
roots


Parameter
Description

return

The
descriptions
for
the
three
main
categories

The
labels
for
them
are




•

“DAIS
CONDITION
CATEGORY?



•

“DAIS
TRACKING
CATEGORY?



•

“DAIS
SIMPLE
CATEGORY?



get
event
properties



Get
all
properties
that
are
used
in
the
supervision
of
the
source
type
for
a
specific
category

The
corresponding
OPC
method
is
IOPCEventServer

QueryEventAttributes






Parameter

Description



category

The
identification
of
the
categories
to
get
the
properties
for




return

A
sequence
of
property
identifications




Browse
categories

get
main
reasons








DAIS

AlarmsAndEvents

Category

IHome
DAIS

AlarmsAndEvents

Category

IHome

Client

ClientGet
the
three
main
reasons
find
by
parent



Get
the
sub
reasons
for
one
main
reason

For
each
sub
reason
explore
1

the
condition
spaces
that
are
defined

refer
to
ConditionSpace
2

the
properties
that
are
used
in
supervision
of
sources
Continue
and
explore
all
main
reasons

Figure
5-19
Browse
category
interaction
Browse
properties





DAIS

Alarm
sAndE
vents

Category

IHom
e
DAIS

AlarmsAndEvents

Category

IHome

Client

ClientGet
the
three
m
ain
categories
Get
the
sub
categories
for
one
main
category

For
each
sub
category
explore
1

the
condition
spaces
that
are
defined

refer
to
ConditionSpace
2

the
properties
that
are
used
in
supervision
of
sources
Continue
and
explore
all
main
categories

get
main
categories




find
by
parent




Figure
5-20
Browse
properties
interaction



















The
IO
interface
for
alarms
&
events
only
supports
callbacks
and
the
client
shall
implement
callback


The
event
notifications
sent
over
the
callback
are
of
three
different
formats
corresponding
to
the
three
main
categories

simple
event

condition
event

and
tracking
event


All
three
event
formats
have
the
common
part
Event

The
tracking
event
has
additional
information
on
the
operator
and
the
condition
event
has
additional
information
on
the
source
condition
causing
the
notification


In
OPC
the
IO
interface
is
implemented
by
the
interface
IOPCEventSink


Source

from
DAISAESource

Event
source


ResourceID
source
pathname


string
time
stamp


DateTime
message


string
event
format


EventFormat
category


ResourceID
category
name


string
severity


unsigned
long
property
values


PropertyValues
11SimpleCategory

from
DAISAECa
tegory

SimpleEvent
11ConditionCategory

from
DAISAECategory


ConditionEvent
condition
space
name


string
condition
space


ResourceID
condition
name


string
condition
number


unsigned
long
ack
required


boolean
active
time


DateTime
event
id


EventID
change
specification


ChangeSpec
source
condition
op
state


SourceConditionOpState
dais
quality


Quality
TrackingCategory

from
DAISAECategory


TrackingEvent
actor
name


string
11DAIS

AlarmsAndEvents

IO

Callback
<<Interface>>
on
event


on
read
complete





11

Figure
5-21
DAIS
alarms
and
events
IO
IDL
in
UML












File

DAISAEIO
idl#ifndef

DAIS
AEIO
IDL#define

DAIS
AEIO
IDL#pragma
prefix
"omg
org"#include
<DAISAECommon
idl>
module
DAIS
{module
AlarmsAndEvents
{module
IO
{
typedef
unsigned
long
ChangeSpec
const
ChangeSpec
CHANGE
ACTIVE
STATE
=
0x0001

const
ChangeSpec
CHANGE
ACK
STATE
=
0x0002

const
ChangeSpec
CHANGE
ENABLE
STATE
=
0x0004

const
ChangeSpec
CHANGE
QUALITY
=
0x0008

const
ChangeSpec
CHANGE
SEVERITY
=
0x0010

const
ChangeSpec
CHANGE
CONDITION
=
0x0020

const
ChangeSpec
CHANGE
MESSAGE
=
0x0040

const
ChangeSpec
CHANGE
ATTRIBUTE
=
0x0080


struct
SimpleEvent
{
ResourceID
source

string
source
pathname

DateTime
time
stamp

string
message

EventFormat
event
format

ResourceID
category

string
category
name

unsigned
long
severity

PropertyValues
property
values


}


struct
TrackingEvent
{
string
actor
name

}


struct
ConditionEvent
{
string
condition
space
name

ResourceID
condition
space

string
condition
name

unsigned
long
condition
number

boolean
ack
required

DateTime
active
time

EventID
event
id

ChangeSpec
change
specification

SourceConditionOpState
source
condition
op
state

Quality
dais
quality


}


struct
Event
{
SimpleEvent
simple
event

TrackingEvent
tracking
event

ConditionEvent
condition
event


}
typedef
sequence<Event>
Events

interface
Callback{
void
on
event

in
boolean
refresh
in
boolean
last
refresh
in
Events
the
events




void
on
read
complete

in
Events
the
events
in
unsigned
long
transaction
id



}

}
}
}

#endif




DAIS
AEIO
IDL

ChangeSpec

A
flag
word
having
a
number
of
flags
telling
what
change
caused
the
event
notification




Flag

Description



CHANGE
ACTIVE
STATE

Alarm
active
has
changed




CHANGE
ACK
STATE

Alarm
acknowledge
has
changed




CHANGE
ENABLE
STATE

Enable
has
changed




CHANGE
QUALITY

The
quality
has
changed




CHANGE
SEVERITY

The
severity
has
changed




CHANGE
CONDITION

A
condition
has
become
active
inactive




CHANGE
MESSAGE

The
message
has
been
updated




CHANGE
ATTRIBUTE

An
attribute
value
has
changed




SimpleEvent

A
struct
holding
the
simple
event
data




Member

Description



source

The
identification
of
the
source
for
which
the
event
notification
was
created




source
pathname

The
full
pathname
of
the
source




time
stamp

Time
of
the
event
occurrence
-
for
conditions

time
that
the
condition
transitioned
into
the
new
state
or
condition


For
example

if
the
event
notification
is
for
acknowledgment
of
a
condition

this
would
be
the
time
that
the
condition
became
acknowledged




message

Event
notification
message
describing
the
event




event
format

The
identification
for
one
of
the
three
main
formats






category

The
identification
of
the
sub-category
why
the
event
notification
was
sent




category
name

The
label
for
the
sub-category




severity

The
severity
for
the
event

a
number
between
0
and
1000




property
values

A
sequence
of
property
values
as
selected
by
the
select
returned
properties


method




TrackingEvent

A
struct
holding
tracking
event
data




Member

Description



actor
name

The
name
of
the
actor
or
operator
causing
the
event




notification




ConditionEvent

A
struct
holding
the
condition
event
data




Member

Description



condition
space
name

The
name
of
the
condition
space
that
caused
the
event
notification




condition
space

Identification
of
the
condition
space




condition
name

The
name
of
the
condition
that
caused
the
event
notification




condition
number

Identification
of
the
condition




ack
required

An
indication
that
an
alarm
is
generated
and
that
an
acknowledgment
is
required




active
time

The
time
when
the
condition
became
active




event
id

An
identification
of
the
event
notification




change
specification

Indicates
to
the
client
which
properties
of
the
condition
have
changed




source
condition
op
state

The
new
state
for
the
source
condition




quality

The
quality




Event

A
struct
composed
of
the
three
above
event
structs

The
simple
event
struct
always
contains
valid
information
and
which
of
the
tracking
or
condition
event
structs
are
valid
is
decided
from
the
main
reason
simple
event
member




Member

Description



simple
event

The
simple
event




tracking
event

The
tracking
event




condition
event

The
condition
event




Callback

The
callback
object
implemented
by
the
client
and
used
by
the
server
to
send
event
notifications


on
event



The
callback
method




Parameter

Description



refresh

Indicates
if
this
callback
is
due
to
a
refresh




last
refresh

Indicates
if
this
callback
is
the
last
in
a
sequence
initiated
by
a
refresh




the
events

A
sequence
of
event
notifications




return

None




on
read
complete



A
callback
method
for
the
async
read
history


method

After
an
async
read
history


call
from
a
client
the
server
will
deliver
the
historical
events
using
this
method

There
is
no
corresponding
OPC
method




Parameter

Description



the
events

A
sequence
of
historical
events




transaction
id

The
transaction
number
matching
the
client
call
number




Event
notification
callbacks





DAIS

Alarm
sAndEvents

IO

Callback

DAIS

AlarmsAndEvents

Ints
Subscription

M
anagerntO

Callback

DAIS

AlarmsAndEve


DAIS

AlarmsAndEves

Subscription

Manageron
event



on
event



The
on
event
method
is
called
by
the
server
at
1

expiration
of
the
subscription
buffer
time
timeout
2

subscription
event
buffer
full
For
alarms
the
client
may
want
to
call
SourceCondition

ack
alarm


to
acknowledge

A
ll
inform
ation
needed
for
doing
this
is
found
in
the
event
notifications

Figure
5-22
Event
notification
callbacks
interaction

Refresh
callbacks





DAIS

AlarmsAndEvents

IO

Callback

DAIS

AlarmsAndEvents

IO

CallbackOn
event
is
called
as
response
to
a
refresh

All
refresh
calls
are
made
with
the
refresh
parameter
set
and
the
last
call
also
has
the
last
refresh
parameter
set



DAIS

AlarmsAndEvents

Subscription

Manager
DAIS

AlarmsAndEvents

Subscription

Manageron
event




Figure
5-23
Refresh
callbacks
interaction












Alarms
and
events
are
generated
by
a
source
represented
by
Source

A
source
might
be
a
single
measurement

a
collection
of
measurements

or
some
other
object

A
collection
of
measurements
may
represent
a
complex
real
world
object
like
a
generator
or
some
control
function
for
the
generator

A
source
has
a
name
property

The
source
is
also
associated
with
a
type
that
describes
any
additional
properties

If
a
DAIS
server
implements
both
data
access
and
alarms
&
events

a
client
shall
expect
there
is
a
mapping
between
sources
and
nodes

A
client
shall
however
not
make
assumptions
on
how
the
mapping
is
made
and
use
the
method
translate
to
item
ids


to
get
the
mapping
from
the
server


Sources
are
organized
in
areas
represented
by
Area

An
area
typically
represents
area
of
responsibility
concerning
supervision
and
operation
of
sources

Areas
may
however
also
be
used
for
other
groupings
of
sources

Areas
can
be
hierarchically
structured
to
allow
creation
of
hierarchically
organized
responsibilities

Multiple
views
of
areas
are
supported


Alarms
and
events
are
categorized

Category
represents
the
categories

Three
main
categories
are
defined
and
must
be
implemented
by
a
server




•	
simple
-
describing
events
that
do
not
have
an
explicitly
modeled
condition
space




•	
tracking
-
describing
events
generated
due
to
an
operator
action




•	
condition
-
describing
events
generated
based
on
an
explicitly
modeled
condition
space




The
categories
simple
and
tracking
are
used
for
events

and
the
category
condition
is
used
for
alarms


For
each
main
category
it
is
possible
to
define
a
number
of
sub-categories

A
server
is
free
to
implement
any
sub-categories

Each
type
of
source
is
expected
to
be
associated
with
at
least
one
main
category
and
one
or
more
sub-categories
for
each
main
category

The
main
categories
are
not
expected
to
have
an
association
with
a
source
type

Subcategories
however
are
all
expected
to
have
an
associated
source
type


A
Condition
category
is
associated
with
one
or
more
condition
spaces

ConditionSpace
represents
a
condition
space

Depending
on
how
limits
are
applied
to
the
properties
defined
by
the
type
associated
with
a
condition
category
it
is
possible
to
create
a
space
consisting
of
different
discrete
conditions

Condition
describes
each
discrete
condition

A
condition
space
will
have
a
number
of
conditions
defined
for
it

A
Transition
describes
each
possible
transition
between
a
pair
of
conditions

The
alarms
&
event
session
does
not
however
provide
any
methods
for
direct
access
of
transitions

When
a
transition
is
traversed
a
condition
event
is
generated


A
source
may
be
associated
with
one
or
more
condition
spaces

Each
such
association
has
status
information
describing
the
current
condition

The
association
and
its
data
are
called
SourceCondition

The
source
condition
is
identified
by
its
associated
source
and
condition
space


A
source
is
of
a
specific
type

e
g


measurement

breaker

generator

tank

etc


and
the

type
has
one
or
more
properties
in
the
same
way
as
a
node

refer
to
Section
4
1
1


“Nodes

Items

Types

and
Properties
?
on
page
4-2


A
category
may
have
any
number

of
properties
associated
with
it

An
alarm
or
event
may
contain
values
for
the
properties
associated
with
the
corresponding
category

This
is
used
to
convey
additional
server
specific
information
with
alarms
and
events

Specification
of
what
properties
are
associated
with
categories
is
outside
the
scope
of
this
specification


The
described
classes
are
shown
in
Figure
5-2

The
attributes
are
described
later
with
the
description
of
the
interfaces




0

0
n
n



AreaSourceComponent

from
DAISAEArea

id


ResourceID
name


string
description


string
Area
Source

from
DAISAEArea



from
DAISAESourc
e


+aggregated
types

+parent

0

n0

n


0

0
n
n



Type

from
DAIST
ype




0

0
n
n


11



1

n1

n


11


0

0
n
n



Property

from
DAISProperty




0

n0

n



SourceCondition

from
DA
I
S
AES
o
urceCon
di
t
ion

condition
op
state


DAISConditionOpState
quality


DAIS

Quality
last
acknowledge


DateTime
condition
last
active


DateTime
condition
space
last
active


DateTime
condition
space
last
inactive


DateTime
acknowledger
name


string
comment


string



0

0
n
n



0

0
n
n



0

n0

n


11



1

n
11

n1



1

n1

n


0

0
n
n


11

+conditions



ConditionSpace

from
DAISAECondition
Space

id


ResourceID
name


string
description


string
Condition

from
DAISAECondition
Space

id
number


unsigned
long
name


string
description


string
severity


unsigned
long
condition
logic


string



SimpleCategory

fro
m
DAISAECate
gory

TrackingCategory

fro
m
DAISAECate
gory

ConditionEvent

from
DAISAEIO

ConditionCategory

fro
m
DAISAECate
gory

11Category

f
ro
m
DAIS
A
ECateg
ory




11


0

n0

n

+active
condition


11



Transition

from
DAISAECo
nditionSp
ac
e




0

n0

n

Figure
5-2
DAIS
Alarms
and
Events
Information
Model

The
objects
in
DAIS
alarms
and
events
has
the
following
mapping
to
OPC
alarms
and
events
objects




DAIS
A&E
object

OPC
A&E
object



Source

Source



Area

Area



Property

EventAttribute



Category

EventCategory



The
categories

simple

tracking
and
condition

EventType



ConditionSpace

Condition



Condition

SubCondition



SourceCondition

SourceCondition








In
OPC
there
is
a
recommendation
of
what
properties
are
expected
to
be
supported
by
an
alarm
&
event
server

The
recommended
properties
are
shown
in
Table
5-1

The
column
names
correspond
to
the
attributes
in
the
Property
class


Table
5-1
Recommended
Properties
Table
5-1
Recommended
Properties



label

id

canonical

data
type

description



Condition
Status

300

STRING
TYPE

The
current
alarm
or
condition
status
associated
with
the
Item

for
example

“NORMAL
?
“ACTIVE
?
“HI
ALARM?





Alarm
Quick
Help

301

STRING
TYPE

A
short
text
string
providing
a
brief
set
of
instructions
for
the
operator
to
follow
when
this
alarm
occurs




Alarm
Area
List

302

STRING
TYPE
sequence

An
array
of
strings
indicating
the
plant
or
alarm
areas
that
include
this
ItemID




Primary
Alarm
Area

303

STRING
TYPE

A
string
indicating
the
primary
plant
or
alarm
area
including
this
ItemID




Condition
Logic

304

STRING
TYPE


An
arbitrary
string
describing
the
test
being
performed

for
example

“High
Limit
Exceeded?
or
“TAG
PV
>=
TAG
HILIM?


Refer
to
Section
5
2
7
3

“Condition
Logic
?
on
page
5-38







Limit
Exceeded

305

STRING
TYPE

For
multistate
alarms

the
condition
exceeded

for
example

HIHI

HI

LO

LOLO





Deadband

306

DOUBLE
TYPE

Deadband



HiHi
Limit

307

DOUBLE
TYPE

HiHi
Limit



Hi
Limit

308

DOUBLE
TYPE

Hi
Limit



Lo
Limit

309

DOUBLE
TYPE

Lo
Limit



LoLo
Limit

310

DOUBLE
TYPE

LoLo
Limit



Rate
of
Change
Limit

311

DOUBLE
TYPE

Rate
of
Change
Limit



Deviation
Limit

312

DOUBLE
TYPE

Deviation
Limit




3124999


Reserved
by
OPC













In
OPC
there
is
a
recommendation
of
what
properties
are
expected
to
be
supported
by
an
alarm
&
event
server

The
recommended
properties
are
shown
in
Table
5-1

The
column
names
correspond
to
the
attributes
in
the
Property
class


Table
5-1
Recommended
Properties
Table
5-1
Recommended
Properties



label

id

canonical

data
type

description



Condition
Status

300

STRING
TYPE

The
current
alarm
or
condition
status
associated
with
the
Item

for
example

“NORMAL
?
“ACTIVE
?
“HI
ALARM?





Alarm
Quick
Help

301

STRING
TYPE

A
short
text
string
providing
a
brief
set
of
instructions
for
the
operator
to
follow
when
this
alarm
occurs




Alarm
Area
List

302

STRING
TYPE
sequence

An
array
of
strings
indicating
the
plant
or
alarm
areas
that
include
this
ItemID




Primary
Alarm
Area

303

STRING
TYPE

A
string
indicating
the
primary
plant
or
alarm
area
including
this
ItemID




Condition
Logic

304

STRING
TYPE


An
arbitrary
string
describing
the
test
being
performed

for
example

“High
Limit
Exceeded?
or
“TAG
PV
>=
TAG
HILIM?


Refer
to
Section
5
2
7
3

“Condition
Logic
?
on
page
5-38







Limit
Exceeded

305

STRING
TYPE

For
multistate
alarms

the
condition
exceeded

for
example

HIHI

HI

LO

LOLO





Deadband

306

DOUBLE
TYPE

Deadband



HiHi
Limit

307

DOUBLE
TYPE

HiHi
Limit



Hi
Limit

308

DOUBLE
TYPE

Hi
Limit



Lo
Limit

309

DOUBLE
TYPE

Lo
Limit



LoLo
Limit

310

DOUBLE
TYPE

LoLo
Limit



Rate
of
Change
Limit

311

DOUBLE
TYPE

Rate
of
Change
Limit



Deviation
Limit

312

DOUBLE
TYPE

Deviation
Limit




3124999


Reserved
by
OPC
















The
dependencies
among
the
different
IDL
files
are
shown
in
Figure
5-3




DAISAESession
DAISAESubscription
DAISAEIO
DAISAESource
Condition
DAISConditionSpace
DAISAEReason
DAISAESource
DAISAEArea
DAISServer

from
Server

DAISSession

from
Com
m
on

DAISProperty

from
Common

DAISNode

from
Common

DAISCommon

from
Common

DAISAECommon
DAISType

from
Com
m
on


Figure
5-3
Dependencies
between
alarms
and
events
IDL
files


















File

DAISAECommon
idl
#ifndef

DAIS
AECOMMON
IDL
#define

DAIS
AECOMMON
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{

typedef
ResourceID
EventID


struct
ResourceError

{
Error
err

ResourceID
id


string
reason

}

typedef
sequence<ResourceError>
ResourceErrors





error
codesconst
Error
RES
ERROR
DAISOK=
0
const
Error


RES
ERROR
UNKOWN
RESOURCE=
1

typedef
unsigned
longSourceConditionOpState
const
SourceConditionOpStateCONDITION
ENABLED=
0x0001
const
SourceConditionOpStateCONDITION
ACTIVE=
0x0002
const
SourceConditionOpStateCONDITION
ACKED=
0x0004

typedef
unsigned
short
EventFormat
const
EventFormat
OPC
SIMPLE
EVENT
=
0x0001
const
EventFormat
OPC
TRACKING
EVENT
=
0x0002
const
EventFormat
OPC
CONDITION
EVENT=
0x0004
const
EventFormat
OPC
ALL
EVENTS
=
0x0007
}
}
#endif




DAIS
AECOMMON
IDL
EventID
A
ResourceID
uniquely
identifying
an
event
notification


ResourceError

A
struct
for
reporting
of
resource
related
errors




Member

Description



err

An
error
code
as
described
below




id

The
identification
of
the
resource




reason

An
additional
text
explaining
the
error




ResourceErrors

ResourceErrors
is
a
sequence
containing
errors

If
no
errors
are
present

no
entry
shall
be
included
in
the
sequence
rather
than
including
a
large
number
of
no
errors

An
empty
sequence
means
no
errors


Error

The
error
codes
for
ResourceError




Member

Description



RES
ERROR
DAISOK

No
error




RES
ERROR
UNKOWN
RESOURCE

The
resource
was
not
found




SourceConditionOpState

Flag
word
holding
for
the
operational
state
of
a
SourceCondition

The
definitions
of
the
state
variable
in
the
flag
word
are
listed
below




Flag

Description



CONDITION
ENABLED

The
Condition
is
enabled
and
supervision
is
active




CONDITION
ACTIVE

The
Condition
is
active

that
is

the
supervision
has
determined
that
a
fault
has
activated
the
condition




CONDITION
ACKED

The
Condition
alarm
has
been
acknowledged




The
combinations
of
the
state
variables
result
in
eight
states

The
valid
SourceCondition
operational
states
are
listed
below




State

Description



Disabled

Not
supervised
by
server




Enabled

Inactive

Acked

Supervised
by
server

no
fault
detected
and
all
alarms
are
acknowledged




Enabled

Inactive

Unacked

Supervised
by
server

no
fault
detected
and
unacknowledged
alarms
exist




Enabled

Active

Unacked

Supervised
by
server

a
fault
is
detected
and
unacknowledged
alarms
exist




Enabled

Active

Acked

Supervised
by
server

a
fault
is
persistent
and
all
alarms
are
acknowledged




When
enabled
the
state
{Enabled

Inactive

Acked}
is
entered
and
from
there
the
supervision
will
generate
the
appropriate
state
depending
on
the
result
of
the
supervision

Each
state
change
results
in
sending
an
alarm
and
event
notification

All
notifications
contain
the
state


EventFormat

This
constant
tells
the
format
of
an
event




Member

Description



OPC
SIMPLE
EVENT

The
event
is
a
simple
event




OPC
TRACKING
EVENT

The
event
is
a
tracking
event




OPC
CONDITION
EVENT

The
event
is
a
condition
event




OPC
ALL
EVENTS

This
constant
value
is
used
to
ask
for
all
event
formats
in
a
subscription
set
up




















The
DAIS

AlarmsAndEvents

Session
object
implements
the
alarms
&
events
service
on
a
per
client
basis

An
alarm
&
event
session
object
has
a
number
of
services
provided
by
one
singleton
home
object
each

Each
home
object
provides
methods
for
manipulation
of
the
data
of
the
specific
type
they
provide


The
session
object
corresponds
to
an
OPCEventServer
object




DAIS

ShutdownCallback

from
DAISSessi
on

<<Interface>>



DAIS

AlarmsAndEvents

Session
<<Interface>>
subscription
home




DAIS

AlarmsAndEnvents

Subscription

Home
area
home




DAIS

AlarmsAndEvents

Area

IHome
source
home




DAIS

AlarmsAndEvents

Source

IHome
condition
space
home




DAIS

AlarmsAndEnvents

ConditionSpace

Home
source
condition
home




DAIS

AlarmsAndEvents

SourceCondition

IHome
reason
home




DAIS

AlarmsAndEvents

Category

IHome
type
home




DAIS

Type

IHome
property
home




DAIS

Property

IHome
DAIS

Session

from
DAISSessi
on

<<Interface>>
status




DAIS

SessionStatus
1
01callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy




10

1


0

10

1



11



Client

f
rom
DA
ISServ
er




11



DAIS

AlarmsAndEvents

Area

IHome

from
DAISAEArea

<<Interface>>



0

0
*
*



11



DAIS

AlarmsAndEvents

IO

Callback

f
ro
m
DAISAE
I
O

<<Interface>>



11



DAIS

AlarmsAndEvents

Source

IHome

f
rom
DA
ISAE
Sourc
e

<<Interface>>



0

0
1
1



11



11



DAIS

AlarmsAndEvents

ConditionSpace

IHome

from
DAISAECondi
ti
onSpace


<<Interface>>
DAIS

AlarmsAndEvents

SourceCondition

IHome

f
ro
m
DA
ISAE
Sourc
eConditi
on

<<Interface>>



DAIS

AlarmsAndEvents

Category

IHome

from
DAISAECategory

<<Interface>>
DAIS

AlarmsAndEvents

Subscription

IHome

from
DAISAESu
bscriptio
n

<<Interface>>



11



11



11



11
0


0

n



DAIS

AlarmsAndEvents

Subscription

Manager

fro
m
DAISAESubsc
ri
pti
on

<<Interface>>



11



DAIS

Property

IHome

from
DAISProperty

<<Interface>>

Figure
5-4
DAIS
alarms
and
events
session
IDL
in
UML














File

DAISAESession
idl
#ifndef

DAIS
AESERVER
IDL
#define

DAIS
AESERVER
IDL
#pragma
prefix
"omg
org"




Common
Information#include
<DAISType
idl>#include
<DAISProperty
idl>#include
<DAISSession
idl>



Events
and
Alarms#include
<DAISAESubscription
idl>#include
<DAISAEArea
idl>#include
<DAISAESource
idl>#include
<DAISAEConditionSpace
idl>#include
<DAISAESourceCondition
idl>#include
<DAISAECategory
idl>#include
<DAISAEIO
idl>
module
DAIS
{module
AlarmsAndEvents
{
interface
Session


DAIS

Session
{
readonly
attribute
Subscription

IHome
subscription
home


readonly
attribute
Area

IHome
area
home


readonly
attribute
Source

IHome
source
home


readonly
attribute
ConditionSpace

IHome
condition
space
home


readonly
attribute
SourceCondition

IHome
source
condition
home


readonly
attribute
Category

IHome
category
home


readonly
attribute
Type

IHome
type
home


readonly
attribute
Property

IHome
property
home

}
}
}

#endif




DAIS
AESESSION
IDL


Session

Session
is
an
object
implementing
the
alarms
&
events
functions

It
inherits
common
functionality
as
shut
down
callbacks
and
session
status
from
DAIS

AlarmsAndEvents

Session


subscription
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Subscription

IHome
object


area
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Area

IHome
object


source
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Source

IHome
object


condition
space
home

A
read
only
attribute
holding
a
reference
to
a
singleton
ConditionSpace

IHome
object


source
condition
home

A
read
only
attribute
holding
a
reference
to
a
singleton
SourceCondition

IHome
object


category
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Category

IHome
object


type
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Type

IHome
object


property
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Property

IHome
object


















A
DAIS

AlarmsAndEvents

Subscription

Manager
is
an
object
holding
a
filter
specification
set
up
by
a
client

The
filter
is
used
to
specify
what
notifications
shall
be
sent
to
the
client

A
server
can
support
various
filter
functions
and
a
client
can
ask
the
DAIS

AlarmsAndEvents

Subscription

IHome
object
what
filter
functions
are
supported

The
subscription
home
is
also
used
to
create
any
number
of
subscription
manager
objects

Each
subscription
manager
shall
be
associated
with
a
client
implemented
callback
object
so
that
the
server
can
send
alarm
and
event
notifications
to
the
client


A
server
may
optionally
support
an
event
history

The
event
history
shall
record
all
alarms
and
events
appearing
in
a
server

The
method
async
read
history


gives
clients
access
to
the
event
history

The
size
of
the
event
history
is
server
specific
and
outside
the
control
of
a
client


In
OPC
the
Subscription
interface
corresponds
to
the
interface
IOPCEventSubscription




DAIS

AlarmsAndEvents

Subscription

IHome
query
available
filters


create
subscription


<<Interface>>



0

0
1
1



11






DAIS

AlarmsAndEvents

IO

Callback

from
DAISAEIO

<<Interface>>



0

n0

n



11



DAIS

AlarmsAndEvents

Subscription

Manager
callback




DAIS

AlarmsAndEvents

IO

Callback
callback
in
callback


DAIS

AlarmsAndEvents

IO

Callback

set
filter


get
filter


select
returned
properties


get
returned
properties


refresh


asynch
read
history


cancel


get
state


set
state


clone


destroy


<<Interface>>



11


0

0
n
n



PropertySelection
category


ResourceID
properties


PropertyIDs



11






11



11



DAIS

AlarmsAndEvents

Subscription

FilterSpec
reason
filter


ReasonFilter
low
severity


unsigned
long
high
severity


unsigned
long
source
filter


SourceFilter
type
filter


TypeIDs
DAIS

AlarmsAndEvents

Subscription

State
active


boolean
buffer
time


unsigned
long
max
size


unsigned
long
keep
alive
time


unsigned
long
11
Figure
5-5
DAIS
alarms
and
events
subscription
IDL
in
UML











File

DAISAESubscription
idl
#ifndef

DAIS
AESUBSCRIPTION
IDL
#define

DAIS
AESUBSCRIPTION
IDL
#pragma
prefix
"omg
org"
#include
<DAISAEIO
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Subscription
{

struct
State
{
boolean
active

unsigned
long
buffer
time

unsigned
long
max
size

unsigned
long
keep
alive
time


}


struct
OPCSourceFilter
{
ServerItemIdentifications
areas

ServerItemIdentifications
sources


}

typedef
short
SourceFilterType
const
SourceFilterType
OPC
SOURCE
FILTER
TYPE
=
1
const
SourceFilterType
XPATH
SOURCE
FILTER
TYPE
=
2

union
SourceFilter
switch
SourceFilterType

{
case
OPC
SOURCE
FILTER
TYPE



OPCSourceFilter
opc
source
filters

case
XPATH
SOURCE
FILTER
TYPE


string
xpath
source
filter

}


typedef
short
CategoryFilterType
const
CategoryFilterType
OPC
REASON
FILTER
TYPE
=
1
const
CategoryFilterType
XPATH
REASON
FILTER
TYPE=
2

union
CategoryFilter
switch
ReasonFilterType

{
case
OPC
CATEGORY
FILTER
TYPE


ServerItemIdentifications
opc
category
filters

case
XPATH
CATEGORY
FILTER
TYPE


string
xpath
category
filter

}


struct
FilterSpec
{
EventFormat
event
format

CategoryFilter
category
filter

unsigned
long
low
severity

unsigned
long
high
severity


SourceFilter
source
filter

ResourceIDs
type
filter

}


struct
PropSelection
{
ResourceID
category

PropertyIDs
properties


}
typedef
sequence<PropSelection>
PropSelections

enum
ReadDirection
{
READ
FORWARDS

READ
BAKWARDS

}


typedef
unsigned
long
CancelID


interface
Manager

{
exception
BusyDueToRefresh{string
reason
}

exception
HistoryNotImplemented{string
reason
}


attribute
IO

Callback
callback


void
set
filter

in
FilterSpec
filer
spec

raises

BusyDueToRefresh


FilterSpec
get
filter





void
select
returned
properties

in
PropSelections
prop
selections


PropSelections
get
returned
properties

in
ResourceIDs
categories


CancelID
refresh



raises

BusyDueToRefresh



CancelID
async
read
history


in
DateTime
start
time

in
unsigned
long
number
of
events

in
ReadDirection
direction

in
unsigned
long
transaction
id



raises

HistoryNotImplemented



void
cancel

in
CancelID
cancel
id


void
refresh



raises

BusyDueToRefresh



void
refresh
with
history

in
DateTime
start
time
in
DateTime
end
time


raises

HistoryNotImplemented



void
cancel
refresh





State
get
state





State

set
state


in
State
subscription
spec

Manager
clone





void
destroy




}


typedef
unsigned
longFilter
const
Filter
FILTER
BY
EVENT
FORMAT
=
0x0001
const
Filter
FILTER
BY
CATEGORY
=
0x0002
const
Filter
FILTER
BY
SEVERITY
=
0x0004
const
Filter
FILTER
BY
AREA
=
0x0008
const
Filter
FILTER
BY
SOURCE
=
0x0010
const
Filter
FILTER
WITH
XPATH
=
0x0020
const
Filter
FILTER
BY
SOURCE
TYPE
=
0x0040

interface
IHome{
Filter
query
available
filters





Manager
create
subscription


in
State
subscription
spec

out
State

revised
subscr
spec



}
}
}
}

#endif




DAIS
AESUBSCRIPTION
IDL

State
A
struct
describing
the
state
for
the
subscription




Member

Description



active

Indicates
if
the
subscription
is
active

that
is

is
sending
data
on
the
call
back
interface

Events
that
are
appearing
in
the
server
will
be
lost
for
clients
connected
to
inactive
subscriptions




buffer
time

The
requested
buffer
time
in
milliseconds

This
is
a
minimum
time
-
do
not
send
event
notifications
any
faster
that
this
UNLESS
max
size
is
greater
than
0

in
which
case
the
server
will
send
an
event
notification
sooner
to
obey
the
max
size
value

A
value
of
0
for
buffer
time
means
that
the
server
should
send
event
notifications
as
soon
as
it
gets
them


This
parameter
along
with
the
max
size
parameter
is
used
to
improve
communications
efficiency
between
client
and
server

This
parameter
is
a
recommendation
from
the
client

and
the
server
is
allowed
to
ignore
the
parameter

The
server
will
return
the
buffer
time
it
is
actually
providing
in
revised
buffer
time




max
size
The
requested
maximum
number
of
events
that
will
be
sent
in
a
single
callback

A
value
of
0
means
that
there
is
no
limit
to
the
number
of
events
that
will
be
sent
in
a
single
callback

Note
that
a
value
of
max
size
greater
than
0

may
cause
the
server
to
make
callbacks
more
frequently
than
specified
by
buffer
time
when
a
large
number
of
events
are
being
generated
in
order
to
limit
the
number
of
events
to
the
max
size

This
parameter
is
a
recommendation
from
the
client
and
the
server
is
allowed
to
ignore
this
parameter

The
server
will
return
the
actual
number
of
events
it
is
actually
providing
in
revised
max
size


keep
alive
time
The
time
in
milliseconds
for
the
server
to
send
a
callback
to
client

The
intention
is
to
indicate
to
the
client
that
the
server
is
alive
and
avoid
the
need
to
"poll"
the
server
to
check
it
is
alive

If
no
data
is
available
an
empty
message
is
sent

If
the
time
is
less
than
the
buffer
time
the
buffer
time
is
used


OPCSourceFilter

The
struct
specifies
source
filtering
by
enumerating
the
areas
and
sources
the
way
OPC
does
it




Member

Description



areas

A
sequence
of
ResourceIDs
for
the
areas
that
shall
be
notified

All
sources
below
an
area
node
will
be
notified




sources

A
sequence
of
ResourceIDs
for
sources
that
shall
be
notified

An
empty
sequence
means
all
sources
shall
be
notified




SourceFilter

The
union
specifies
OPCSourceFiltering
or
XPath
filtering

A
prerequisite
for
XPath
filtering
is
that
the
area
and
source
hierarchy
has
an
XML
mapping

The
same
mapping

is
used
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?
on

page
3-25
with
the
additional
comments





•

an
Area
corresponds
to
a
Node

Area
inherits
Node





•

a
Source
corresponds
to
a
Node

Source
inherits
Node







Member

Description



opc
source
filters

An
OPCSourceFilter



xpath
source
filter

An
XPath
filter




CategoryFilter

The
union
specifies
OPC
style
filtering
or
XPath
filtering
of
categories

A
prerequisite
for
XPath
filtering
is
that
the
resource
hierarchy
has
an
XML
mapping

The
same

mapping
is
used
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?

on
page
3-25
with
the
additional
comments



•
a
Resource
corresponds
to
a
Node

Resource
inherits
Node





Member

Description



opc
category
filters

An
OPCSourceFilter



xpath
reason
filter

An
XPath
filter



FilterSpec

A
struct
holding
the
specification
for
how
the
server
shall
filter
notifications
sent
to
the
client

The
struct
is
used
to
specify
the
filtering
a
client
wants
a
server
to
do
for
it

All
specified
filter
criterias
shall
be
fulfilled
for
a
notification
to
be
sent




Member

Description



event
format

An
EventFormat
bit
mask
specifying
the
event
formats
to
be
returned




reasons

A
sequence
of
CategoryFilter
for
the
categories
for
which
the
client
wants
to
get
notifications

Observe
that
specifying
a
main
category

for
example

Simple

Tracking

Condition

will
result
in
notifications
for
all
sub-categories
specified
for
that
main
category




low
severity

The
client
wants
all
events
with
greater
or
equal
severity




high
severity

The
client
wants
all
events
with
less
or
equal
severity




sources

A
SourceFilter
for
the
sources
that
shall
be
notified




types

A
sequence
of
TypeIDs
for
the
types
that
shall
be
notified




PropSelection

A
struct
identifying
what
properties
shall
be
included
in
an
event
notification
for
a
specific
reason




Member

Description



reason

The
reason
for
which
the
property
selection
is
made




properties

A
sequence
of
PropertyIDs
for
the
selected
properties




ReadDirection

An
enumeration
that
tells
if
a
read
of
history
shall
be
forward
or
backwards
in
time




Member

Description



READ
FORWARDS

Read
events
after
the
given
start
time




READ
BAKWARDS

Read
events
before
the
given
start
time




Manager

An
object
managing
subscription
and
filtering
of
event
notifications
per
client


BusyDueToRefresh

An
exception
stating
that
a
refresh
is
already
going
on


HistoryNotImplemented

An
exception
stating
that
the
server
does
not
record
the
event
history


callback

An
attribute
holding
a
reference
to
the
callback
object

The
client
is
required
to
update
the
attribute
with
a
by
the
client
implemented
callback
object
to
get
event
notifications
from
the
server

The
attribute
corresponds
to
the
IConnectionPoint
interface
in
OPC


set
filter



The
method
updates
the
filter
specification

A
try
to
change
the
filter
spec
during
an
ongoing
refresh
will
give
an
exception

The
method
corresponds
to
IOPCEventSubscriptionMgt

SetFilter






Member

Description



filer
spec

The
filter
specification




return

none




get
filter



The
method
gets
the
filter
specification

The
method
corresponds
to
IOPCEventSubscriptionMgt

GetFilter






Member
Description
return
The
filter
specification


select
returned
properties



The
method
sets
what
properties
shall
be
included
in
a
notification
specified
per
reason

The
method
corresponds
to
IOPCEventSubscriptionMgt

SelectReturnedAttributes






Member

Description



prop
selections

A
sequence
specifying
what
properties
to
include
per
reason




return

none




get
returned
properties



The
method
gets
what
properties
currently
are
included
in
a
notification
specified
per
category

The
method
corresponds
to
IOPCEventSubscriptionMgt

GetReturnedAttributes






Member

Description



categories

The
categories
for
that
shall
be
used
to
fetch
the
properties




return

A
sequence
specifying
what
properties
currently
are
included
per
reason




refresh



The
method
forces
notifications
for
all
currently
active
source
conditions

The
notifications
will
not
include
the
history
but
only
the
current
source
condition
operational
state

The
method
corresponds
to
IOPCEventSubscriptionMgt

Refresh






Member
Description
return
A
server
generated
handle
that
the
client
can
use
to
cancel
the
operation


async
read
history



The
method
read
historic
events
recorded
by
the
server

If
the
server
does
not
support
recording
of
alarms
and
events
an
exception
is
raised

No
corresponding
method
exists
in
OPC




Member

Description



start
time

The
time
where
to
start
the
read

An
unspecified
time

=0

will
make
the
read
start
from
the
oldest
recorded
event




number
of
events

The
max
number
of
events
to
deliver
as
a
response
to
the
read
operation






Member

Description



direction

Tells
if
events
before
or
after
the
start
time
shall
be
read




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
server
generated
handle
that
the
client
can
use
to
cancel
the
operation




cancel



The
method
cancels
an
ongoing
refresh
operation
or
async
read
history


operations

It
corresponds
to
IOPCEventSubscriptionMgt

CancelRefresh






Member

Description



cancel
id

A
server
generated
handle
that
is
given
back
to
the
server
when
a
started
operation
shall
be
cancelled




return

none




get
state



The
method
gets
the
current
subscription
state
and
corresponds
to
IOPCEventSubscriptionMgt

GetState






Member
Description
return
The
current
subscription
state


set
state



The
method
sets
the
current
subscription
state
and
corresponds
to
IOPCEventSubscriptionMgt

SetState



The
actual
parameters
set
are
returned
and
an
exception
is
raised
if
any
input
parameters
are
not
accepted
and
hence
changed




Member

Description



subscription
spec

New
state
wanted
for
the
subscription




return

The
accepted
subscription
state




clone



The
method
creates
a
copy
of
the
subscription


5-22
Data
Acquisition
from
Industrial
Systems

v1
1
June
2005



Member
Description
return
The
copied
subscription


destroy



The
method
destroys
the
subscription
object


Filter

A
flag
word
holding
flags
specifying
the
filters
that
are
implemented
by
the
server




Flag

Description



FILTER
BY
MAIN
CATEGORY

Filtering
by
main
category
is
supported




FILTER
BY
CATEGORY

Filtering
by
sub-category
is
supported




FILTER
BY
SEVERITY

Filtering
by
severity
is
supported




FILTER
BY
AREA

Filtering
by
area
is
supported




FILTER
BY
SOURCE

Filtering
by
source
is
supported




FILTER
WITH
XPATH

XPath
as
filter
description
is
supported




FILTER
BY
SOURCE
TYPE

Filtering
by
source
type
is
supported




IHome

A
factory
object
for
creation
of
subscription
management
objects


query
available
filters



Gets
by
the
server
implemented
filter
functions

The
method
corresponds
to
IOPCEventServer

QuearyAvailableFilters






Member
Description
return
Filter
specification
flagword


create
subscription



Creates
a
subscription
management
object

An
invalid
state
will
give
an
exception




Member
Description
subscription
spec
State
wanted
for
the
subscription




revised
subscr
spec
State
accepted
by
the
server

return
The
new
subscription
manager

Set
up
Subscription

query
available
filters








Client
Client


DAIS

AlarmsAndEvents

Subscription

IHome
DAIS

AlarmsAndEvents

Subscription

IHome


DAIS

AlarmsAndEvents

Subscription

Manager
DAIS

AlarmsAndEvents

Subscription

ManagerCheck
what
filters
are
supported
by
the
server
create
subscription



callback
DAISCallback

select
returned
properties



Set
the
callback
for
server
to
use
set
filter



Set
up
filter
to
get
only
wanted
event
notifications
Select
what
property
values
to
be
included
in
event
notifications
Do
some
browsing
to
prepare
for
setting
up
the
filter

Browse
for
reasons

areas
and
sources
Do
some
browsing
to
prepare
for
selecting
properties

Figure
5-6
Set
up
subscription
interaction

Refresh





Client

Client


DAIS

AlarmsAndEvents

Subscription

Manager

DAIS

AlarmsAndEvents
backbac
Subscription

Manager


DAIS

AlarmsAndEvents

IO

Call

DAIS

AlarmsAndEvents

IO

Callkrefresh



Initiate
transfer
of
the
currently
active
source
conditions
on
event



on
event



on
event



As
many
notifications
sent
as
needed
to
report
all
source
conditions

Figure
5-7
Refresh
interaction

















An
area
is
a
specialization
of
a
node
and
is
a
collection
of
other
areas
or
sources

Areas
are
intended
for
arbitrary
hierarchical
structuring
of
sources
for
various
usages

for
example

areas
for
authority
or
responsibility



DAIS

AlarmsAndEvents

Area

IHome
is
used
for
browsing
the
area
hierarchy

The
find
methods
in
the
interface
correspond
to
the
IOPCEventAreaBrowser
with
the
filter
type
parameter
set
to
OPC
AREA

The
interface
also
implements
the
following
OPC
methods




•

IOPCEventServer

EnableConditionByArea





•

IOPCEventServer

DisableConditionByArea







DAIS

AlarmsAndEvents

Area

IHome
<<Interface>>
get
root


enable
condition


disable
condition


DAIS

Node

IHome

from
DAISNode

<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids





AreaSourceComponent
id


ResourceID
name


string
description


string
Area
Source

from
DAISAESource

11


0

0
n
n


0

0
n
n

+parent




Figure
5-8
DAIS
alarms
and
events
area
IDL
in
UML











File

DAISAEArea
idl
#ifndef

DAIS
AEAREA
IDL
#define

DAIS
AEAREA
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Area
{

interface
IHome


Node

IHome
{
ResourceID
get
root




ResourceErrors
enable
condition


in
ResourceIDs
areas




ResourceErrors
disable
condition



in
ResourceIDs
areas





}


}
}
}


#endif




DAIS
AEAREA
IDL

IHome

An
object
for
browsing
areas


get
root



A
method
to
get
the
root
node
for
the
area
tree




Member
Description
return
The
root
area
node


enable
condition



A
method
for
enabling
the
sources
contained
by
the
specified
areas

The
corresponding
OPC
method
is
IOPCEventServer

EnableConditionByArea






Member

Description



areas

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




disable
condition



A
method
for
disabling
the
sources
contained
by
the
specified
areas

The
corresponding
OPC
method
is
IOPCEventServer

DisableConditionByArea






Member

Description



areas

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




Browse
areas

get
root








Client

Client


DAIS

AlarmsAndEvents

Area

IHome

DAIS

AlarmsAndEvents

Area

IHome


DAIS

Node

Iterator
DAIS

Node

IteratorGet
the
root
of
all
areas
find
by
parent



next
n



Repeat
find
by
parent
and
next
n
until
the
areas
are
explored

Figure
5-9
Browse
areas
interaction

















A
source
is
a
specialization
of
a
node
and
is
contained
by
areas

A
source
represents
an
object
that
generates
alarms
and
events

A
source
may
have
source
conditions

The
find
methods
in
the
interface
correspond
to
the
IOPCEventAreaBrowser
with
the
filter
type
parameter
set
to
OPC
SOURCE

The
interface
also
implements
the
following
OPC
methods




•

IOPCEventServer

TranslateToItemIDs



•

IOPCEventServer

EnableConditionBySource





•

IOPCEventServer

DisableConditionBySource






DAIS

Node

IHome

from
DAISNode

<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids


DAIS

AlarmsAndEvents

Source

IHome
<<Interface>>
translate
to
item
ids


enable
conditions


disable
conditions


Source
0

n
1
0

n10

n
1
0

n1Area

from
DAI
SAEArea

AreaSourceComponent

from
DAI
SAEArea

id


ResourceID
name


string
description


string
0

n
+parent
0

n


SourceCondition

from
DAISAESo
urceCon
di
tion

condition
op
state


DAISConditionOpState
quality


DAIS

Quality
last
acknowledge


DateTime
condition
last
active


DateTime
condition
space
last
active


DateTime
condition
space
last
inactive


DateTime
acknowledger
name


string
comment


string

Figure
5-10
DAIS
alarms
and
events
source
IDL
in
UML











File

DAISAESource
idl
#ifndef


DAIS
AESOURCE
IDL
#define


DAIS
AESOURCE
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Source
{

interface
IHome


Node

IHome
{
exception
PropertyDidNotTranslate{string
reason
}


ItemIDs
translate
to
item
ids

in
ResourceID
source
in
ResourceID
category
in
PropertyIDs
properties


raises

PropertyDidNotTranslate



ResourceErrors
enable
conditions

in
ResourceIDs
sources


ResourceErrors
disable
conditions

in
ResourceIDs
sources



}
}
}
}

#endif





DAIS
AESOURCE
IDL

IHome

An
object
for
browsing
sources
at
areas


PropertyDidNotTranslate

An
exception
telling
that
one
or
more
properties
did
not
translate
to
ItemIDs


translate
to
item
ids



A
method
for
translation
of
information
about
a
source
to
ItemIDs
for
use
with
the
data
access
interface

If
one
or
more
properties
did
not
translate
to
ItemIDs

an
exception
is
raised

The
corresponding
OPC
method
is
IOPCEventServer

TranslateToItemIDs






Member

Description



source

The
identification
of
the
source




category

The
identification
of
the
category




properties

A
sequence
of
properties
for
which
ItemIDs
are
wanted




return

A
sequence
of
ItemIDs

Properties
that
did
not
translate
to
ItemIDs
are
returned
as
empty
ItemIDs




enable
conditions



A
method
for
enabling
the
specified
sources

The
corresponding
OPC
method
is
IOPCEventServer

EnableConditionBySource






Member

Description



sources

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




disable
conditions



A
method
for
disabling
specified
sources

The
corresponding
OPC
method
is
IOPCEventServer

DisableConditionBySource






Member

Description



sources

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed



Browse
sources





Client

Client


DAIS

AlarmsAndEvents

Source

IHome

DAIS

AlarmsAndEvents

Source

IHome


DAIS

Node

Iterator
DAIS

Node

Iteratorfind
by
parent



Get
all
sources
that
has
a
given
area
as
parent
next
n



Repeat
getting
all
found
sources
from
the
iterator
and
continue
with
another
area
as
parent
to
sources

Repeat
this
until
all
wanted
sources
are
explored

For
each
source
inspect
the
conditions
it
might
have

refer
to
ConditionSpace

Figure
5-11
Browse
sources
interaction

















A
condition
space
describes
a
set
of
conditions

that
is

it
is
a
space
of
conditions

Each
condition
space
is
associated
with
a
particular
sub-reason
of
the
main
reason
ConditionReason

Each
condition
has
logic
describing
when
the
condition
is
active

The
logic
is
described
in
a
little
language
having
the
following
constructs




•

arithmetic
operators



•

logic
operators



•

references
to
properties



The
referred
properties
must
be
included
in
the
set
of
properties
defined
by
the
associated
reason

The
little
language
grammar
is
server
specific
and
is
outside
the
scope
of
this
specification

Transitions
describe
what
transitions
between
conditions
are
allowed

The
interface
does
not
support
exploration
of
the
transitions


In
OPC
the
ConditionSpace
interface
is
implemented
by
the
methods




•

IOPCEventServer

QueryConditionNames





•

IOPCEventServer

QuerySubConditionNames










DAIS

AlarmsAndEvents

ConditionSpace

IHome
<<Interface>>
find


find
each


find
by
reason


find
by
source


get
names


get
ids


11


0

0
n
n



1

1
n
n


11



ConditionSpace
id


ResourceID
name


string
description


string
Condition
id
number


unsigned
long
name


string
description


string
severity


unsigned
long
condition
logic


string



ConditionCategory

from
DAISAECategory




1

1
n
n

+conditions



0

0
n
n



0

n0

n



Transition



11


11


0

0
n
n




ConditionEvent


from
DAISAEIO


Figure
5-12
DAIS
alarms
and
events
condition
space
IDL
in
UML











File

DAISAEConditionSpace
idl
#ifndef

DAIS
AECONDITION
SPACE
IDL
#define

DAIS
AECONDITION
SPACE
IDL
#pragma
prefix
"omg
org"
#include
<DAISAECommon
idl>

module
DAIS
{module
AlarmsAndEvents
{module
ConditionSpace
{
struct
ConditionDescription
{




unsigned
long

id
number





string

name





string

condition
logic





unsigned
long

severity





string

descrip




}






typedef
sequence<ConditionDescription>
ConditionDescriptions


struct
Description

{

ResourceID
id


string
name


string
descrip


ConditionDescriptionsconditions

}

typedef
sequence<
Description
>Descriptions


interface
IHome
{

exception
UnknownResourceID
{string
reason
}


Description
find


in
ResourceID
condition
space


raises

UnknownResourceID



Descriptions
find
each


in
ResourceIDs
condition
spaces


raises

UnknownResourceID



Descriptions
find
by
category


in
ResourceID
category


raises

UnknownResourceID



Descriptions
find
by
source


in
ResourceID
source


raises

UnknownResourceID



Strings
get
names


in
ResourceIDs
condition
spaces




ResourceIDs
get
ids


in
Strings
names




}
}
}
}
#endif




DAIS
AECONDITION
SPACE
IDL
ConditionDescription

A
struct
describing
a
condition




Member

Description



id
number

A
numeric
identification
unique
within
the
condition
space




name

The
name
of
the
condition




condition
logic


The
logic
telling
when
the
condition
is
active

Refer
to
Section
5
2
7
3

“Condition
Logic
?
on
page
5-38
for
a
description





severity

Severity
is
a
number
between
1
and
1000
having
the
following
meaning

•
Low
severity
1-200
•
Medium
low
severity
201-400
•
Medium
severity
401-600
•
Medium
high
severity
601-800
•
High
severity
801-1000



description

A
text
that
to
be
included
in
event
notifications
when
the
condition
is
active




Description

A
struct
describing
the
condition
space




Member

Description



id

A
ResourceID
identifying
the
condition
space




name

The
name
of
the
condition
space




description

A
description
of
the
condition
space




conditions

A
sequence
of
the
conditions
creates
the
condition
space

In
OPC
the
conditions
are
called
sub-conditions
and
are
retrieved
by
the
method
IOPCEventServer

QuerySubConditionNames






IHome

An
object
for
browsing
the
condition
spaces
defined
by
a
server


find



A
method
for
getting
the
description
of
a
condition
space




Parameter

Description



condition
space

A
ResourceID
identifying
a
condition
space




return

The
condition
space
description




find
each



A
method
for
getting
the
descriptions
for
a
number
of
condition
spaces




Parameter

Description



condition
spaces

A
sequence
of
ResourceID
identifying
condition
spaces




return

A
sequence
of
condition
space
descriptions




find
by
category



A
method
for
finding
all
condition
spaces
defined
for
a
category

The
corresponding
OPC
method
is
IOPCEventServer

QueryConditionNames






Parameter

Description



category

A
ResourceID
identifying
the
category
for
which
to
get
the
condition
spaces




return

A
sequence
of
condition
space
descriptions




find
by
source



A
method
for
finding
all
condition
spaces
defined
for
a
source

The
corresponding
OPC
method
is
IOPCEventServer

QuerySourceConditions






Parameter

Description



source

A
ResourceID
identifying
the
source
for
which
to
get
the
condition
spaces




return

A
sequence
of
condition
space
descriptions




get
names



A
method
translating
a
number
of
condition
space
identifications
into
name
strings




Parameter

Description



condition
spaces

A
sequence
of
ResourceID
identifying
condition
spaces




return

A
sequence
of
condition
space
names

Non-translated
identifications
are
returned
as
empty
strings




get
ids



A
method
translating
a
number
of
condition
space
names
into
ResourceIDs




Parameter

Description



names

A
sequence
of
condition
space
names




return

A
sequence
of
condition
space
ResourceIDs

Non-
translated
identifications
are
returned
as
NULL
IDs



Browse
condition
space
by
source





Client

Client


DAIS

AlarmsAndEvents

ConditionSpace

IHome

DAIS

AlarmsAndEvents

ConditionSpace

IHomefind
by
source



Get
all
condition
space
descriptions
for
one
source

Explore
each
condition
space
from
the
retrieved
descriptions

Figure
5-13
Browse
condition
space
by
source
interaction

Browse
condition
space
by
category





Client

CliAlrmsAndEvents

ConditionSpace

IHomeAent


DAIS

a

DAIS

larmsAndEvents

ConditionSpace

IHome
find
by
category






Get
all
condition
space
description
for
one
category

Explore
each
condition
space
from
the
retrieved
descriptions


Figure
5-14
Browse
condition
space
by
category
interaction








The
reduced
XPath
language
as
defined
in
Section
3
1
12

“Logical
Expressions
and

Navigation
?
on
page
3-25
is
used
to
describe
the
condition
logic

This
allows

description
of
a
path
through
a
data
structure
picking
up
property
values
to
be
used
in
a
logical
expression


A
common
case
is
property
values
at
objects
associated
with
a
source

hence
the
starting
point
for
navigation
is
the
source

An
example
from
the
CIM
model
where
the

Measurement
is
the
source
can
be
found
in
Figure
4-3
on
page
4-6



Examples
how
to
use
DAIS
Expressions
starting
from
a
source
are
shown
below


Measurement
value
<
500
assuming
that
the
tested
value
is
an
element
at
the
source


MeasurementValue[id
MeasurementValue
MeasurementValueSource

label='telemetry']

MeasurementValue
value
<
id
Measurement
LimitSets
[LimitSet
label
=
'summer']
Limit[label
=
'highalarm']
Limit
value


Based
on
the
model
in
Figure
4-3
on
page
4-6

the
XML
example
in
Section
3
1
12


“Logical
Expressions
and
Navigation
?
on
page
3-25
and
the
source
as
a
Measurement





















A
source
condition
associates
a
source
with
a
condition
space

A
source
condition
holds
the
current
information
specific
to
a
source
using
a
particular
condition
space
for
the
supervision

A
source
condition
has
no
own
identification
and
is
identified
by
its
associated
source
and
condition
space

Information
about
a
source
condition
is
accessed
through
its
home
object

In
OPC
a
source
condition
is
sometimes
called
an
instance
of
a
condition


In
OPC
the
SourceCondition
interface
is
implemented
by
the
methods




•

IOPCEventServer

QuerySourceConditions





•

IOPCEventServer

AckCondition











DAIS

AlarmsAndEvents

SourceCondition

IHome
<<Interface>>
find


find
each


ack
condition





Source

from
DAISAE
Source



11


0

0
n
n


11


0

0
n
n



0

0
n
n


11



11



ConditionSpace

from
DAISAE
Condi
ti
onSpace

id


ResourceID
name


string
description


string
Condition

from
DA
ISAECondi
ti
onSpace

id
number


unsigned
long
name


string
description


string
severity


unsigned
long
condition
logic


string
SourceCondition
condition
op
state


DAISConditionOpState
quality


DAIS

Quality
last
acknowledge


DateTime
condition
last
active


DateTime
condition
space
last
active


DateTime
condition
space
last
inactive


DateTime
acknowledger
name


string
comment


string
0

0
n
+active
condition

n
Figure
5-15
DAIS
alarms
and
events
source
condition
IDL
in
UML











File

DAISAESourceCondition
idl
#ifndef

DAIS
AESOURCE
CONDITION
IDL
#define

DAIS
AESOURCE
CONDITION
IDL
#pragma
prefix
"omg
org"
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
SourceCondition
{

struct
Id
{




ResourceID

source





ResourceID

condition
space




}






typedef
sequence<Id>Ids


struct
Description
{

Id
source
condition
SourceConditionOpState
source
condition
op
state
unsigned
long
active
condition
string
ac
logic
unsigned
long
ac
severity
string
ac
description
Quality
dais
quality
DateTime
last
acknowledge
DateTime
condition
last
active
DateTime
condition
space
last
active
DateTime
condition
space
last
inactive
string
acknowledger
name
string
comment
PropertyValues
property
values

}
typedef
sequence<
Description
>
Descriptions

struct
AcknowledgeSpec
{
Id
source
condition

DateTime
active
time

EventID
cookie


}

typedef
sequence<AcknowledgeSpec>AcknowledgeSpecs


interface
Iterator
{
boolean
next
n






in

unsigned
long

n





out

Descriptions

c
descriptions












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownId
{string
reason
}

exception
UnknownPropertyID
{string
reason
}


Description
find


in
Id
source
condition

in
PropertyIDs
properties



raises

UnknownId

UnknownPropertyID



Iterator
find
each

in
Ids
source
conditions

in
PropertyIDs
properties



raises

UnknownId

UnknownPropertyID



Descriptions
ack
condition


#endif




DAIS
AESOURCE
CONDITION
IDL
Id




in
string

acknowledger
name





in
string

comment





in
AcknowledgeSpecs
ack
spec











}






}
}
}






A
struct
that
identifies
a
source
condition




Member

Description



source

The
ResourceID
identifying
the
associated
source




condition
space

The
ResourceID
identifying
the
associated
condition
space




Description

A
struct
describing
the
source
condition




Member

Description



id

The
Id
identifying
the
source
condition




source
condition
op
state

The
DAISSourceConditionOpState
as
described
in
Section
5
2
2

“Alarms
and
Events
Common
IDL
Definitions
?
on
page
5-7




active
condition

The
identification
number
of
the
currently
active
condition




ac
logic

The
condition
logic
from
the
active
condition




ac
severity

The
severity
from
the
active
condition




ac
description

The
description
from
the
active
condition




dais
quality

The
quality
is
evaluated
from
the
qualities
from
the
properties
used
to
evaluate
the
condition
logic




last
acknowledge

The
last
time
the
condition
was
acknowledged




condition
last
active

Time
for
the
latest
condition
transition






condition
space
last
active

The
last
time
when
the
condition
space
became
active

After
this
time
more
condition
transitions
may
occur

The
condition
last
active
will
then
be
later
than
condition
space
last
active




condition
space
last
inactive

The
last
time
when
the
condition
space
became
inactive

that
is

no
conditions
are
active




acknowledger
name

The
name
of
the
client
making
an
acknowledge




comment

A
comment
passed
by
the
client
making
an
acknowledge




property
values

A
sequence
of
property
values
as
selected
by
the
Manager

select
returned
properties
call




AcknowledgeSpec

A
struct
specifying
an
alarm
to
acknowledge




Member

Description



source
condition

The
Id
identifying
the
source
condition
for
which
to
acknowledge
an
alarm




active
time

The
time
when
the
alarm
activated




cookie

A
identification
of
the
alarm




Iterator

A
standard
iterator

Refer
to
Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10


IHome

An
object
for
browsing
and
accessing
source
conditions


UnknownDAISSourceConditionID

An
exception
telling
that
the
source
condition
identification
was
not
recognized


UnknownPropertyID

An
exception
telling
that
a
property
identification
was
not
recognized


find



A
method
for
getting
the
description
of
a
source
condition

The
corresponding
OPC
method
is
IOPCEventServer

GetConditionState






Parameter

Description



source
condition

A
ResourceID
identifying
a
source
condition




return

The
source
condition
description




find
each



A
method
for
getting
the
descriptions
for
a
number
of
source
conditions




Parameter

Description



condition
spaces

A
sequence
identifying
source
conditions




return

A
sequence
of
source
condition
descriptions




ack
condition



A
method
to
acknowledge
a
number
of
source
condition
alarms

The
corresponding
OPC
method
is
IOPCEventServer

AckCondition






Parameter

Description



acknowledger
name

The
name
of
the
client
making
the
acknowledge




comment

A
comment
to
be
added
to
source
condition
and
the
event




ack
spec

A
sequence
specifying
the
alarms
to
acknowledge




return

A
sequence
containing
descriptions
for
the
acknowledged
source
conditions



Inspect
a
specific
source
condition





Client

Client


D
A
IS



AlarmsA
ndEvent
s

S
ourc
eC
ondition


IH
ome
DAIS

AlarmsAndEvents

SourceCondition

IHomefind



Get
all
det
ails
on
a
s
pec
ific
source
c
ondit
on

Figure
5-16
Inspect
a
specific
source
condition
interaction

Acknowledge
alarm





Client

Client


DAIS

AlarmsAndEvents

SourceCondition

IHom
e
DAIS

AlarmsAndEvents

SourceCondition

IHomeack
condition



Acknolwedge
a
set
of
source
conditions
in
one
call

Figure
5-17
Acknowledge
alarm
interaction











These
are
definitions
for
manipulating
categories

A
category
describes
the
content
of
an
event

Categories
are
organized
in
a
two
level
hierarchy
where
the
first
level
has
the
three
mandatory
main
categories

simple

condition

and
tracking


Simple
category
does
not
have
a
condition
space

refer
to
ConditonSpace


Generation
of
simple
category
alarms
or
events
is
coded
into
some
software
function
and
cannot
be
configured

Typical
simple
categories
are
program
errors

hardware
device
failures

etc


Sources
of
different
types

e
g


breaker
position

breaker
current

generator
active
power

etc


may
have
different
ways
an
alarm
or
event
is
generated

e
g


breaker
trip

breaker
over
current

generator
active
power
generation
overload

etc



Condition
categories
are
used
to
describe
source
type
specific
alarm
and
event
contents


The
alarm
and
event
generation
for
a
condition
category
is
configured
using
condition
spaces
and
several
condition
spaces
can
be
created
for
the
same
condition
category

This
corresponds
to
variations
in
the
way
the
alarms
and
events
are
generated
using
different
condition
logics


Alarms
or
events
due
to
operator
actions
or
control
functions

intended
alarms
or
events
rather
than
spontaneous

use
tracking
categories


A
category
has
a
set
of
properties
associated
with
it

Some
or
all
of
the
properties
may
be
included
in
event
notifications

The
properties
come
from
the
source
type
and
may
be
used
by
the
logic
generating
an
event
notification


The
get
main

category



method
is
used
to
obtain
the
three
main
categories

The
find
by
parent


is
used
to
get
the
child
categories

Categories
at
this
second
level
correspond
to
the
OPC
EventCategories

The
labels
for
the
three
main
reasons
are
“DAIS
CONDITION
CATEGORY
?
“DAIS
TRACKING
CATEGORY
?
and
"DAIS
SIMPLE
CATEGORY
?

In
OPC
the
Category
interface
is
implemented
by
the
methods
IOPCEventServer

QueryEventCategories


and
IOPCEventServer

QueryEventAttributes






TrackingCategory
SimpleCategory
ConditionCategory
DAIS

AlarmsAndEvents

Category

IHome
get
main
categories


get
event
properties


<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids



from
DAISNode

<<Interface>>
Node
id


ResourceID
label


string
type


ResourceID

f
rom
DA
ISNo
de

1
0

10

nCategory

Figure
5-18
DAIS
alarms
and
events
categories
IDL
in
UML












File

DAISAECategory
idl
#ifndef

DAIS
AECATEGORY
IDL
#define

DAIS
AECATEGORY
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>

module
DAIS
{module
AlarmsAndEvents
{module
Category{
interface
IHome


Node

IHome
{
Node

Descriptions
get
main
categories





PropertyIDs
get
event
properties

in
ResourceID
category



}

}
}
}

#endif




DAIS
AECATEGORY
IDL

IHome

IHome
is
an
object
for
browsing
categories

Most
of
the
browsing
functionality
is
inherited
from
DAIS

Node


get
main
categories



Get
the
three
main
categories

simple

condition

and
tracking

The
three
main
categories
appear
as
three
different
roots


Parameter
Description

return

The
descriptions
for
the
three
main
categories

The
labels
for
them
are




•

“DAIS
CONDITION
CATEGORY?



•

“DAIS
TRACKING
CATEGORY?



•

“DAIS
SIMPLE
CATEGORY?



get
event
properties



Get
all
properties
that
are
used
in
the
supervision
of
the
source
type
for
a
specific
category

The
corresponding
OPC
method
is
IOPCEventServer

QueryEventAttributes






Parameter

Description



category

The
identification
of
the
categories
to
get
the
properties
for




return

A
sequence
of
property
identifications




Browse
categories

get
main
reasons








DAIS

AlarmsAndEvents

Category

IHome
DAIS

AlarmsAndEvents

Category

IHome

Client

ClientGet
the
three
main
reasons
find
by
parent



Get
the
sub
reasons
for
one
main
reason

For
each
sub
reason
explore
1

the
condition
spaces
that
are
defined

refer
to
ConditionSpace
2

the
properties
that
are
used
in
supervision
of
sources
Continue
and
explore
all
main
reasons

Figure
5-19
Browse
category
interaction
Browse
properties





DAIS

Alarm
sAndE
vents

Category

IHom
e
DAIS

AlarmsAndEvents

Category

IHome

Client

ClientGet
the
three
m
ain
categories
Get
the
sub
categories
for
one
main
category

For
each
sub
category
explore
1

the
condition
spaces
that
are
defined

refer
to
ConditionSpace
2

the
properties
that
are
used
in
supervision
of
sources
Continue
and
explore
all
main
categories

get
main
categories




find
by
parent




Figure
5-20
Browse
properties
interaction



















The
IO
interface
for
alarms
&
events
only
supports
callbacks
and
the
client
shall
implement
callback


The
event
notifications
sent
over
the
callback
are
of
three
different
formats
corresponding
to
the
three
main
categories

simple
event

condition
event

and
tracking
event


All
three
event
formats
have
the
common
part
Event

The
tracking
event
has
additional
information
on
the
operator
and
the
condition
event
has
additional
information
on
the
source
condition
causing
the
notification


In
OPC
the
IO
interface
is
implemented
by
the
interface
IOPCEventSink


Source

from
DAISAESource

Event
source


ResourceID
source
pathname


string
time
stamp


DateTime
message


string
event
format


EventFormat
category


ResourceID
category
name


string
severity


unsigned
long
property
values


PropertyValues
11SimpleCategory

from
DAISAECa
tegory

SimpleEvent
11ConditionCategory

from
DAISAECategory


ConditionEvent
condition
space
name


string
condition
space


ResourceID
condition
name


string
condition
number


unsigned
long
ack
required


boolean
active
time


DateTime
event
id


EventID
change
specification


ChangeSpec
source
condition
op
state


SourceConditionOpState
dais
quality


Quality
TrackingCategory

from
DAISAECategory


TrackingEvent
actor
name


string
11DAIS

AlarmsAndEvents

IO

Callback
<<Interface>>
on
event


on
read
complete





11

Figure
5-21
DAIS
alarms
and
events
IO
IDL
in
UML












File

DAISAEIO
idl#ifndef

DAIS
AEIO
IDL#define

DAIS
AEIO
IDL#pragma
prefix
"omg
org"#include
<DAISAECommon
idl>
module
DAIS
{module
AlarmsAndEvents
{module
IO
{
typedef
unsigned
long
ChangeSpec
const
ChangeSpec
CHANGE
ACTIVE
STATE
=
0x0001

const
ChangeSpec
CHANGE
ACK
STATE
=
0x0002

const
ChangeSpec
CHANGE
ENABLE
STATE
=
0x0004

const
ChangeSpec
CHANGE
QUALITY
=
0x0008

const
ChangeSpec
CHANGE
SEVERITY
=
0x0010

const
ChangeSpec
CHANGE
CONDITION
=
0x0020

const
ChangeSpec
CHANGE
MESSAGE
=
0x0040

const
ChangeSpec
CHANGE
ATTRIBUTE
=
0x0080


struct
SimpleEvent
{
ResourceID
source

string
source
pathname

DateTime
time
stamp

string
message

EventFormat
event
format

ResourceID
category

string
category
name

unsigned
long
severity

PropertyValues
property
values


}


struct
TrackingEvent
{
string
actor
name

}


struct
ConditionEvent
{
string
condition
space
name

ResourceID
condition
space

string
condition
name

unsigned
long
condition
number

boolean
ack
required

DateTime
active
time

EventID
event
id

ChangeSpec
change
specification

SourceConditionOpState
source
condition
op
state

Quality
dais
quality


}


struct
Event
{
SimpleEvent
simple
event

TrackingEvent
tracking
event

ConditionEvent
condition
event


}
typedef
sequence<Event>
Events

interface
Callback{
void
on
event

in
boolean
refresh
in
boolean
last
refresh
in
Events
the
events




void
on
read
complete

in
Events
the
events
in
unsigned
long
transaction
id



}

}
}
}

#endif




DAIS
AEIO
IDL

ChangeSpec

A
flag
word
having
a
number
of
flags
telling
what
change
caused
the
event
notification




Flag

Description



CHANGE
ACTIVE
STATE

Alarm
active
has
changed




CHANGE
ACK
STATE

Alarm
acknowledge
has
changed




CHANGE
ENABLE
STATE

Enable
has
changed




CHANGE
QUALITY

The
quality
has
changed




CHANGE
SEVERITY

The
severity
has
changed




CHANGE
CONDITION

A
condition
has
become
active
inactive




CHANGE
MESSAGE

The
message
has
been
updated




CHANGE
ATTRIBUTE

An
attribute
value
has
changed




SimpleEvent

A
struct
holding
the
simple
event
data




Member

Description



source

The
identification
of
the
source
for
which
the
event
notification
was
created




source
pathname

The
full
pathname
of
the
source




time
stamp

Time
of
the
event
occurrence
-
for
conditions

time
that
the
condition
transitioned
into
the
new
state
or
condition


For
example

if
the
event
notification
is
for
acknowledgment
of
a
condition

this
would
be
the
time
that
the
condition
became
acknowledged




message

Event
notification
message
describing
the
event




event
format

The
identification
for
one
of
the
three
main
formats






category

The
identification
of
the
sub-category
why
the
event
notification
was
sent




category
name

The
label
for
the
sub-category




severity

The
severity
for
the
event

a
number
between
0
and
1000




property
values

A
sequence
of
property
values
as
selected
by
the
select
returned
properties


method




TrackingEvent

A
struct
holding
tracking
event
data




Member

Description



actor
name

The
name
of
the
actor
or
operator
causing
the
event




notification




ConditionEvent

A
struct
holding
the
condition
event
data




Member

Description



condition
space
name

The
name
of
the
condition
space
that
caused
the
event
notification




condition
space

Identification
of
the
condition
space




condition
name

The
name
of
the
condition
that
caused
the
event
notification




condition
number

Identification
of
the
condition




ack
required

An
indication
that
an
alarm
is
generated
and
that
an
acknowledgment
is
required




active
time

The
time
when
the
condition
became
active




event
id

An
identification
of
the
event
notification




change
specification

Indicates
to
the
client
which
properties
of
the
condition
have
changed




source
condition
op
state

The
new
state
for
the
source
condition




quality

The
quality




Event

A
struct
composed
of
the
three
above
event
structs

The
simple
event
struct
always
contains
valid
information
and
which
of
the
tracking
or
condition
event
structs
are
valid
is
decided
from
the
main
reason
simple
event
member




Member

Description



simple
event

The
simple
event




tracking
event

The
tracking
event




condition
event

The
condition
event




Callback

The
callback
object
implemented
by
the
client
and
used
by
the
server
to
send
event
notifications


on
event



The
callback
method




Parameter

Description



refresh

Indicates
if
this
callback
is
due
to
a
refresh




last
refresh

Indicates
if
this
callback
is
the
last
in
a
sequence
initiated
by
a
refresh




the
events

A
sequence
of
event
notifications




return

None




on
read
complete



A
callback
method
for
the
async
read
history


method

After
an
async
read
history


call
from
a
client
the
server
will
deliver
the
historical
events
using
this
method

There
is
no
corresponding
OPC
method




Parameter

Description



the
events

A
sequence
of
historical
events




transaction
id

The
transaction
number
matching
the
client
call
number




Event
notification
callbacks





DAIS

Alarm
sAndEvents

IO

Callback

DAIS

AlarmsAndEvents

Ints
Subscription

M
anagerntO

Callback

DAIS

AlarmsAndEve


DAIS

AlarmsAndEves

Subscription

Manageron
event



on
event



The
on
event
method
is
called
by
the
server
at
1

expiration
of
the
subscription
buffer
time
timeout
2

subscription
event
buffer
full
For
alarms
the
client
may
want
to
call
SourceCondition

ack
alarm


to
acknowledge

A
ll
inform
ation
needed
for
doing
this
is
found
in
the
event
notifications

Figure
5-22
Event
notification
callbacks
interaction

Refresh
callbacks





DAIS

AlarmsAndEvents

IO

Callback

DAIS

AlarmsAndEvents

IO

CallbackOn
event
is
called
as
response
to
a
refresh

All
refresh
calls
are
made
with
the
refresh
parameter
set
and
the
last
call
also
has
the
last
refresh
parameter
set



DAIS

AlarmsAndEvents

Subscription

Manager
DAIS

AlarmsAndEvents

Subscription

Manageron
event




Figure
5-23
Refresh
callbacks
interaction












The
dependencies
among
the
different
IDL
files
are
shown
in
Figure
5-3




DAISAESession
DAISAESubscription
DAISAEIO
DAISAESource
Condition
DAISConditionSpace
DAISAEReason
DAISAESource
DAISAEArea
DAISServer

from
Server

DAISSession

from
Com
m
on

DAISProperty

from
Common

DAISNode

from
Common

DAISCommon

from
Common

DAISAECommon
DAISType

from
Com
m
on


Figure
5-3
Dependencies
between
alarms
and
events
IDL
files
















File

DAISAECommon
idl
#ifndef

DAIS
AECOMMON
IDL
#define

DAIS
AECOMMON
IDL
#pragma
prefix
"omg
org"
#include
<DAISCommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{

typedef
ResourceID
EventID


struct
ResourceError

{
Error
err

ResourceID
id


string
reason

}

typedef
sequence<ResourceError>
ResourceErrors





error
codesconst
Error
RES
ERROR
DAISOK=
0
const
Error


RES
ERROR
UNKOWN
RESOURCE=
1

typedef
unsigned
longSourceConditionOpState
const
SourceConditionOpStateCONDITION
ENABLED=
0x0001
const
SourceConditionOpStateCONDITION
ACTIVE=
0x0002
const
SourceConditionOpStateCONDITION
ACKED=
0x0004

typedef
unsigned
short
EventFormat
const
EventFormat
OPC
SIMPLE
EVENT
=
0x0001
const
EventFormat
OPC
TRACKING
EVENT
=
0x0002
const
EventFormat
OPC
CONDITION
EVENT=
0x0004
const
EventFormat
OPC
ALL
EVENTS
=
0x0007
}
}
#endif




DAIS
AECOMMON
IDL
EventID
A
ResourceID
uniquely
identifying
an
event
notification


ResourceError

A
struct
for
reporting
of
resource
related
errors




Member

Description



err

An
error
code
as
described
below




id

The
identification
of
the
resource




reason

An
additional
text
explaining
the
error




ResourceErrors

ResourceErrors
is
a
sequence
containing
errors

If
no
errors
are
present

no
entry
shall
be
included
in
the
sequence
rather
than
including
a
large
number
of
no
errors

An
empty
sequence
means
no
errors


Error

The
error
codes
for
ResourceError




Member

Description



RES
ERROR
DAISOK

No
error




RES
ERROR
UNKOWN
RESOURCE

The
resource
was
not
found




SourceConditionOpState

Flag
word
holding
for
the
operational
state
of
a
SourceCondition

The
definitions
of
the
state
variable
in
the
flag
word
are
listed
below




Flag

Description



CONDITION
ENABLED

The
Condition
is
enabled
and
supervision
is
active




CONDITION
ACTIVE

The
Condition
is
active

that
is

the
supervision
has
determined
that
a
fault
has
activated
the
condition




CONDITION
ACKED

The
Condition
alarm
has
been
acknowledged




The
combinations
of
the
state
variables
result
in
eight
states

The
valid
SourceCondition
operational
states
are
listed
below




State

Description



Disabled

Not
supervised
by
server




Enabled

Inactive

Acked

Supervised
by
server

no
fault
detected
and
all
alarms
are
acknowledged




Enabled

Inactive

Unacked

Supervised
by
server

no
fault
detected
and
unacknowledged
alarms
exist




Enabled

Active

Unacked

Supervised
by
server

a
fault
is
detected
and
unacknowledged
alarms
exist




Enabled

Active

Acked

Supervised
by
server

a
fault
is
persistent
and
all
alarms
are
acknowledged




When
enabled
the
state
{Enabled

Inactive

Acked}
is
entered
and
from
there
the
supervision
will
generate
the
appropriate
state
depending
on
the
result
of
the
supervision

Each
state
change
results
in
sending
an
alarm
and
event
notification

All
notifications
contain
the
state


EventFormat

This
constant
tells
the
format
of
an
event




Member

Description



OPC
SIMPLE
EVENT

The
event
is
a
simple
event




OPC
TRACKING
EVENT

The
event
is
a
tracking
event




OPC
CONDITION
EVENT

The
event
is
a
condition
event




OPC
ALL
EVENTS

This
constant
value
is
used
to
ask
for
all
event
formats
in
a
subscription
set
up


















The
DAIS

AlarmsAndEvents

Session
object
implements
the
alarms
&
events
service
on
a
per
client
basis

An
alarm
&
event
session
object
has
a
number
of
services
provided
by
one
singleton
home
object
each

Each
home
object
provides
methods
for
manipulation
of
the
data
of
the
specific
type
they
provide


The
session
object
corresponds
to
an
OPCEventServer
object




DAIS

ShutdownCallback

from
DAISSessi
on

<<Interface>>



DAIS

AlarmsAndEvents

Session
<<Interface>>
subscription
home




DAIS

AlarmsAndEnvents

Subscription

Home
area
home




DAIS

AlarmsAndEvents

Area

IHome
source
home




DAIS

AlarmsAndEvents

Source

IHome
condition
space
home




DAIS

AlarmsAndEnvents

ConditionSpace

Home
source
condition
home




DAIS

AlarmsAndEvents

SourceCondition

IHome
reason
home




DAIS

AlarmsAndEvents

Category

IHome
type
home




DAIS

Type

IHome
property
home




DAIS

Property

IHome
DAIS

Session

from
DAISSessi
on

<<Interface>>
status




DAIS

SessionStatus
1
01callback




DAIS

ShutdownCallback
callback
callback


DAIS

ShutdownCallback

destroy




10

1


0

10

1



11



Client

f
rom
DA
ISServ
er




11



DAIS

AlarmsAndEvents

Area

IHome

from
DAISAEArea

<<Interface>>



0

0
*
*



11



DAIS

AlarmsAndEvents

IO

Callback

f
ro
m
DAISAE
I
O

<<Interface>>



11



DAIS

AlarmsAndEvents

Source

IHome

f
rom
DA
ISAE
Sourc
e

<<Interface>>



0

0
1
1



11



11



DAIS

AlarmsAndEvents

ConditionSpace

IHome

from
DAISAECondi
ti
onSpace


<<Interface>>
DAIS

AlarmsAndEvents

SourceCondition

IHome

f
ro
m
DA
ISAE
Sourc
eConditi
on

<<Interface>>



DAIS

AlarmsAndEvents

Category

IHome

from
DAISAECategory

<<Interface>>
DAIS

AlarmsAndEvents

Subscription

IHome

from
DAISAESu
bscriptio
n

<<Interface>>



11



11



11



11
0


0

n



DAIS

AlarmsAndEvents

Subscription

Manager

fro
m
DAISAESubsc
ri
pti
on

<<Interface>>



11



DAIS

Property

IHome

from
DAISProperty

<<Interface>>

Figure
5-4
DAIS
alarms
and
events
session
IDL
in
UML













File

DAISAESession
idl
#ifndef

DAIS
AESERVER
IDL
#define

DAIS
AESERVER
IDL
#pragma
prefix
"omg
org"




Common
Information#include
<DAISType
idl>#include
<DAISProperty
idl>#include
<DAISSession
idl>



Events
and
Alarms#include
<DAISAESubscription
idl>#include
<DAISAEArea
idl>#include
<DAISAESource
idl>#include
<DAISAEConditionSpace
idl>#include
<DAISAESourceCondition
idl>#include
<DAISAECategory
idl>#include
<DAISAEIO
idl>
module
DAIS
{module
AlarmsAndEvents
{
interface
Session


DAIS

Session
{
readonly
attribute
Subscription

IHome
subscription
home


readonly
attribute
Area

IHome
area
home


readonly
attribute
Source

IHome
source
home


readonly
attribute
ConditionSpace

IHome
condition
space
home


readonly
attribute
SourceCondition

IHome
source
condition
home


readonly
attribute
Category

IHome
category
home


readonly
attribute
Type

IHome
type
home


readonly
attribute
Property

IHome
property
home

}
}
}

#endif




DAIS
AESESSION
IDL


Session

Session
is
an
object
implementing
the
alarms
&
events
functions

It
inherits
common
functionality
as
shut
down
callbacks
and
session
status
from
DAIS

AlarmsAndEvents

Session


subscription
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Subscription

IHome
object


area
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Area

IHome
object


source
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Source

IHome
object


condition
space
home

A
read
only
attribute
holding
a
reference
to
a
singleton
ConditionSpace

IHome
object


source
condition
home

A
read
only
attribute
holding
a
reference
to
a
singleton
SourceCondition

IHome
object


category
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Category

IHome
object


type
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Type

IHome
object


property
home

A
read
only
attribute
holding
a
reference
to
a
singleton
Property

IHome
object
















A
DAIS

AlarmsAndEvents

Subscription

Manager
is
an
object
holding
a
filter
specification
set
up
by
a
client

The
filter
is
used
to
specify
what
notifications
shall
be
sent
to
the
client

A
server
can
support
various
filter
functions
and
a
client
can
ask
the
DAIS

AlarmsAndEvents

Subscription

IHome
object
what
filter
functions
are
supported

The
subscription
home
is
also
used
to
create
any
number
of
subscription
manager
objects

Each
subscription
manager
shall
be
associated
with
a
client
implemented
callback
object
so
that
the
server
can
send
alarm
and
event
notifications
to
the
client


A
server
may
optionally
support
an
event
history

The
event
history
shall
record
all
alarms
and
events
appearing
in
a
server

The
method
async
read
history


gives
clients
access
to
the
event
history

The
size
of
the
event
history
is
server
specific
and
outside
the
control
of
a
client


In
OPC
the
Subscription
interface
corresponds
to
the
interface
IOPCEventSubscription




DAIS

AlarmsAndEvents

Subscription

IHome
query
available
filters


create
subscription


<<Interface>>



0

0
1
1



11






DAIS

AlarmsAndEvents

IO

Callback

from
DAISAEIO

<<Interface>>



0

n0

n



11



DAIS

AlarmsAndEvents

Subscription

Manager
callback




DAIS

AlarmsAndEvents

IO

Callback
callback
in
callback


DAIS

AlarmsAndEvents

IO

Callback

set
filter


get
filter


select
returned
properties


get
returned
properties


refresh


asynch
read
history


cancel


get
state


set
state


clone


destroy


<<Interface>>



11


0

0
n
n



PropertySelection
category


ResourceID
properties


PropertyIDs



11






11



11



DAIS

AlarmsAndEvents

Subscription

FilterSpec
reason
filter


ReasonFilter
low
severity


unsigned
long
high
severity


unsigned
long
source
filter


SourceFilter
type
filter


TypeIDs
DAIS

AlarmsAndEvents

Subscription

State
active


boolean
buffer
time


unsigned
long
max
size


unsigned
long
keep
alive
time


unsigned
long
11
Figure
5-5
DAIS
alarms
and
events
subscription
IDL
in
UML










File

DAISAESubscription
idl
#ifndef

DAIS
AESUBSCRIPTION
IDL
#define

DAIS
AESUBSCRIPTION
IDL
#pragma
prefix
"omg
org"
#include
<DAISAEIO
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Subscription
{

struct
State
{
boolean
active

unsigned
long
buffer
time

unsigned
long
max
size

unsigned
long
keep
alive
time


}


struct
OPCSourceFilter
{
ServerItemIdentifications
areas

ServerItemIdentifications
sources


}

typedef
short
SourceFilterType
const
SourceFilterType
OPC
SOURCE
FILTER
TYPE
=
1
const
SourceFilterType
XPATH
SOURCE
FILTER
TYPE
=
2

union
SourceFilter
switch
SourceFilterType

{
case
OPC
SOURCE
FILTER
TYPE



OPCSourceFilter
opc
source
filters

case
XPATH
SOURCE
FILTER
TYPE


string
xpath
source
filter

}


typedef
short
CategoryFilterType
const
CategoryFilterType
OPC
REASON
FILTER
TYPE
=
1
const
CategoryFilterType
XPATH
REASON
FILTER
TYPE=
2

union
CategoryFilter
switch
ReasonFilterType

{
case
OPC
CATEGORY
FILTER
TYPE


ServerItemIdentifications
opc
category
filters

case
XPATH
CATEGORY
FILTER
TYPE


string
xpath
category
filter

}


struct
FilterSpec
{
EventFormat
event
format

CategoryFilter
category
filter

unsigned
long
low
severity

unsigned
long
high
severity


SourceFilter
source
filter

ResourceIDs
type
filter

}


struct
PropSelection
{
ResourceID
category

PropertyIDs
properties


}
typedef
sequence<PropSelection>
PropSelections

enum
ReadDirection
{
READ
FORWARDS

READ
BAKWARDS

}


typedef
unsigned
long
CancelID


interface
Manager

{
exception
BusyDueToRefresh{string
reason
}

exception
HistoryNotImplemented{string
reason
}


attribute
IO

Callback
callback


void
set
filter

in
FilterSpec
filer
spec

raises

BusyDueToRefresh


FilterSpec
get
filter





void
select
returned
properties

in
PropSelections
prop
selections


PropSelections
get
returned
properties

in
ResourceIDs
categories


CancelID
refresh



raises

BusyDueToRefresh



CancelID
async
read
history


in
DateTime
start
time

in
unsigned
long
number
of
events

in
ReadDirection
direction

in
unsigned
long
transaction
id



raises

HistoryNotImplemented



void
cancel

in
CancelID
cancel
id


void
refresh



raises

BusyDueToRefresh



void
refresh
with
history

in
DateTime
start
time
in
DateTime
end
time


raises

HistoryNotImplemented



void
cancel
refresh





State
get
state





State

set
state


in
State
subscription
spec

Manager
clone





void
destroy




}


typedef
unsigned
longFilter
const
Filter
FILTER
BY
EVENT
FORMAT
=
0x0001
const
Filter
FILTER
BY
CATEGORY
=
0x0002
const
Filter
FILTER
BY
SEVERITY
=
0x0004
const
Filter
FILTER
BY
AREA
=
0x0008
const
Filter
FILTER
BY
SOURCE
=
0x0010
const
Filter
FILTER
WITH
XPATH
=
0x0020
const
Filter
FILTER
BY
SOURCE
TYPE
=
0x0040

interface
IHome{
Filter
query
available
filters





Manager
create
subscription


in
State
subscription
spec

out
State

revised
subscr
spec



}
}
}
}

#endif




DAIS
AESUBSCRIPTION
IDL

State
A
struct
describing
the
state
for
the
subscription




Member

Description



active

Indicates
if
the
subscription
is
active

that
is

is
sending
data
on
the
call
back
interface

Events
that
are
appearing
in
the
server
will
be
lost
for
clients
connected
to
inactive
subscriptions




buffer
time

The
requested
buffer
time
in
milliseconds

This
is
a
minimum
time
-
do
not
send
event
notifications
any
faster
that
this
UNLESS
max
size
is
greater
than
0

in
which
case
the
server
will
send
an
event
notification
sooner
to
obey
the
max
size
value

A
value
of
0
for
buffer
time
means
that
the
server
should
send
event
notifications
as
soon
as
it
gets
them


This
parameter
along
with
the
max
size
parameter
is
used
to
improve
communications
efficiency
between
client
and
server

This
parameter
is
a
recommendation
from
the
client

and
the
server
is
allowed
to
ignore
the
parameter

The
server
will
return
the
buffer
time
it
is
actually
providing
in
revised
buffer
time




max
size
The
requested
maximum
number
of
events
that
will
be
sent
in
a
single
callback

A
value
of
0
means
that
there
is
no
limit
to
the
number
of
events
that
will
be
sent
in
a
single
callback

Note
that
a
value
of
max
size
greater
than
0

may
cause
the
server
to
make
callbacks
more
frequently
than
specified
by
buffer
time
when
a
large
number
of
events
are
being
generated
in
order
to
limit
the
number
of
events
to
the
max
size

This
parameter
is
a
recommendation
from
the
client
and
the
server
is
allowed
to
ignore
this
parameter

The
server
will
return
the
actual
number
of
events
it
is
actually
providing
in
revised
max
size


keep
alive
time
The
time
in
milliseconds
for
the
server
to
send
a
callback
to
client

The
intention
is
to
indicate
to
the
client
that
the
server
is
alive
and
avoid
the
need
to
"poll"
the
server
to
check
it
is
alive

If
no
data
is
available
an
empty
message
is
sent

If
the
time
is
less
than
the
buffer
time
the
buffer
time
is
used


OPCSourceFilter

The
struct
specifies
source
filtering
by
enumerating
the
areas
and
sources
the
way
OPC
does
it




Member

Description



areas

A
sequence
of
ResourceIDs
for
the
areas
that
shall
be
notified

All
sources
below
an
area
node
will
be
notified




sources

A
sequence
of
ResourceIDs
for
sources
that
shall
be
notified

An
empty
sequence
means
all
sources
shall
be
notified




SourceFilter

The
union
specifies
OPCSourceFiltering
or
XPath
filtering

A
prerequisite
for
XPath
filtering
is
that
the
area
and
source
hierarchy
has
an
XML
mapping

The
same
mapping

is
used
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?
on

page
3-25
with
the
additional
comments





•

an
Area
corresponds
to
a
Node

Area
inherits
Node





•

a
Source
corresponds
to
a
Node

Source
inherits
Node







Member

Description



opc
source
filters

An
OPCSourceFilter



xpath
source
filter

An
XPath
filter




CategoryFilter

The
union
specifies
OPC
style
filtering
or
XPath
filtering
of
categories

A
prerequisite
for
XPath
filtering
is
that
the
resource
hierarchy
has
an
XML
mapping

The
same

mapping
is
used
as
described
in
Section
3
1
12

“Logical
Expressions
and
Navigation
?

on
page
3-25
with
the
additional
comments



•
a
Resource
corresponds
to
a
Node

Resource
inherits
Node





Member

Description



opc
category
filters

An
OPCSourceFilter



xpath
reason
filter

An
XPath
filter



FilterSpec

A
struct
holding
the
specification
for
how
the
server
shall
filter
notifications
sent
to
the
client

The
struct
is
used
to
specify
the
filtering
a
client
wants
a
server
to
do
for
it

All
specified
filter
criterias
shall
be
fulfilled
for
a
notification
to
be
sent




Member

Description



event
format

An
EventFormat
bit
mask
specifying
the
event
formats
to
be
returned




reasons

A
sequence
of
CategoryFilter
for
the
categories
for
which
the
client
wants
to
get
notifications

Observe
that
specifying
a
main
category

for
example

Simple

Tracking

Condition

will
result
in
notifications
for
all
sub-categories
specified
for
that
main
category




low
severity

The
client
wants
all
events
with
greater
or
equal
severity




high
severity

The
client
wants
all
events
with
less
or
equal
severity




sources

A
SourceFilter
for
the
sources
that
shall
be
notified




types

A
sequence
of
TypeIDs
for
the
types
that
shall
be
notified




PropSelection

A
struct
identifying
what
properties
shall
be
included
in
an
event
notification
for
a
specific
reason




Member

Description



reason

The
reason
for
which
the
property
selection
is
made




properties

A
sequence
of
PropertyIDs
for
the
selected
properties




ReadDirection

An
enumeration
that
tells
if
a
read
of
history
shall
be
forward
or
backwards
in
time




Member

Description



READ
FORWARDS

Read
events
after
the
given
start
time




READ
BAKWARDS

Read
events
before
the
given
start
time




Manager

An
object
managing
subscription
and
filtering
of
event
notifications
per
client


BusyDueToRefresh

An
exception
stating
that
a
refresh
is
already
going
on


HistoryNotImplemented

An
exception
stating
that
the
server
does
not
record
the
event
history


callback

An
attribute
holding
a
reference
to
the
callback
object

The
client
is
required
to
update
the
attribute
with
a
by
the
client
implemented
callback
object
to
get
event
notifications
from
the
server

The
attribute
corresponds
to
the
IConnectionPoint
interface
in
OPC


set
filter



The
method
updates
the
filter
specification

A
try
to
change
the
filter
spec
during
an
ongoing
refresh
will
give
an
exception

The
method
corresponds
to
IOPCEventSubscriptionMgt

SetFilter






Member

Description



filer
spec

The
filter
specification




return

none




get
filter



The
method
gets
the
filter
specification

The
method
corresponds
to
IOPCEventSubscriptionMgt

GetFilter






Member
Description
return
The
filter
specification


select
returned
properties



The
method
sets
what
properties
shall
be
included
in
a
notification
specified
per
reason

The
method
corresponds
to
IOPCEventSubscriptionMgt

SelectReturnedAttributes






Member

Description



prop
selections

A
sequence
specifying
what
properties
to
include
per
reason




return

none




get
returned
properties



The
method
gets
what
properties
currently
are
included
in
a
notification
specified
per
category

The
method
corresponds
to
IOPCEventSubscriptionMgt

GetReturnedAttributes






Member

Description



categories

The
categories
for
that
shall
be
used
to
fetch
the
properties




return

A
sequence
specifying
what
properties
currently
are
included
per
reason




refresh



The
method
forces
notifications
for
all
currently
active
source
conditions

The
notifications
will
not
include
the
history
but
only
the
current
source
condition
operational
state

The
method
corresponds
to
IOPCEventSubscriptionMgt

Refresh






Member
Description
return
A
server
generated
handle
that
the
client
can
use
to
cancel
the
operation


async
read
history



The
method
read
historic
events
recorded
by
the
server

If
the
server
does
not
support
recording
of
alarms
and
events
an
exception
is
raised

No
corresponding
method
exists
in
OPC




Member

Description



start
time

The
time
where
to
start
the
read

An
unspecified
time

=0

will
make
the
read
start
from
the
oldest
recorded
event




number
of
events

The
max
number
of
events
to
deliver
as
a
response
to
the
read
operation






Member

Description



direction

Tells
if
events
before
or
after
the
start
time
shall
be
read




transaction
id

A
transaction
number
unique
for
the
client

The
number
is
returned
in
the
corresponding
on
read
complete
call




return

A
server
generated
handle
that
the
client
can
use
to
cancel
the
operation




cancel



The
method
cancels
an
ongoing
refresh
operation
or
async
read
history


operations

It
corresponds
to
IOPCEventSubscriptionMgt

CancelRefresh






Member

Description



cancel
id

A
server
generated
handle
that
is
given
back
to
the
server
when
a
started
operation
shall
be
cancelled




return

none




get
state



The
method
gets
the
current
subscription
state
and
corresponds
to
IOPCEventSubscriptionMgt

GetState






Member
Description
return
The
current
subscription
state


set
state



The
method
sets
the
current
subscription
state
and
corresponds
to
IOPCEventSubscriptionMgt

SetState



The
actual
parameters
set
are
returned
and
an
exception
is
raised
if
any
input
parameters
are
not
accepted
and
hence
changed




Member

Description



subscription
spec

New
state
wanted
for
the
subscription




return

The
accepted
subscription
state




clone



The
method
creates
a
copy
of
the
subscription


5-22
Data
Acquisition
from
Industrial
Systems

v1
1
June
2005



Member
Description
return
The
copied
subscription


destroy



The
method
destroys
the
subscription
object


Filter

A
flag
word
holding
flags
specifying
the
filters
that
are
implemented
by
the
server




Flag

Description



FILTER
BY
MAIN
CATEGORY

Filtering
by
main
category
is
supported




FILTER
BY
CATEGORY

Filtering
by
sub-category
is
supported




FILTER
BY
SEVERITY

Filtering
by
severity
is
supported




FILTER
BY
AREA

Filtering
by
area
is
supported




FILTER
BY
SOURCE

Filtering
by
source
is
supported




FILTER
WITH
XPATH

XPath
as
filter
description
is
supported




FILTER
BY
SOURCE
TYPE

Filtering
by
source
type
is
supported




IHome

A
factory
object
for
creation
of
subscription
management
objects


query
available
filters



Gets
by
the
server
implemented
filter
functions

The
method
corresponds
to
IOPCEventServer

QuearyAvailableFilters






Member
Description
return
Filter
specification
flagword


create
subscription



Creates
a
subscription
management
object

An
invalid
state
will
give
an
exception




Member
Description
subscription
spec
State
wanted
for
the
subscription




revised
subscr
spec
State
accepted
by
the
server

return
The
new
subscription
manager

Set
up
Subscription

query
available
filters








Client
Client


DAIS

AlarmsAndEvents

Subscription

IHome
DAIS

AlarmsAndEvents

Subscription

IHome


DAIS

AlarmsAndEvents

Subscription

Manager
DAIS

AlarmsAndEvents

Subscription

ManagerCheck
what
filters
are
supported
by
the
server
create
subscription



callback
DAISCallback

select
returned
properties



Set
the
callback
for
server
to
use
set
filter



Set
up
filter
to
get
only
wanted
event
notifications
Select
what
property
values
to
be
included
in
event
notifications
Do
some
browsing
to
prepare
for
setting
up
the
filter

Browse
for
reasons

areas
and
sources
Do
some
browsing
to
prepare
for
selecting
properties

Figure
5-6
Set
up
subscription
interaction

Refresh





Client

Client


DAIS

AlarmsAndEvents

Subscription

Manager

DAIS

AlarmsAndEvents
backbac
Subscription

Manager


DAIS

AlarmsAndEvents

IO

Call

DAIS

AlarmsAndEvents

IO

Callkrefresh



Initiate
transfer
of
the
currently
active
source
conditions
on
event



on
event



on
event



As
many
notifications
sent
as
needed
to
report
all
source
conditions

Figure
5-7
Refresh
interaction















An
area
is
a
specialization
of
a
node
and
is
a
collection
of
other
areas
or
sources

Areas
are
intended
for
arbitrary
hierarchical
structuring
of
sources
for
various
usages

for
example

areas
for
authority
or
responsibility



DAIS

AlarmsAndEvents

Area

IHome
is
used
for
browsing
the
area
hierarchy

The
find
methods
in
the
interface
correspond
to
the
IOPCEventAreaBrowser
with
the
filter
type
parameter
set
to
OPC
AREA

The
interface
also
implements
the
following
OPC
methods




•

IOPCEventServer

EnableConditionByArea





•

IOPCEventServer

DisableConditionByArea







DAIS

AlarmsAndEvents

Area

IHome
<<Interface>>
get
root


enable
condition


disable
condition


DAIS

Node

IHome

from
DAISNode

<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids





AreaSourceComponent
id


ResourceID
name


string
description


string
Area
Source

from
DAISAESource

11


0

0
n
n


0

0
n
n

+parent




Figure
5-8
DAIS
alarms
and
events
area
IDL
in
UML










File

DAISAEArea
idl
#ifndef

DAIS
AEAREA
IDL
#define

DAIS
AEAREA
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Area
{

interface
IHome


Node

IHome
{
ResourceID
get
root




ResourceErrors
enable
condition


in
ResourceIDs
areas




ResourceErrors
disable
condition



in
ResourceIDs
areas





}


}
}
}


#endif




DAIS
AEAREA
IDL

IHome

An
object
for
browsing
areas


get
root



A
method
to
get
the
root
node
for
the
area
tree




Member
Description
return
The
root
area
node


enable
condition



A
method
for
enabling
the
sources
contained
by
the
specified
areas

The
corresponding
OPC
method
is
IOPCEventServer

EnableConditionByArea






Member

Description



areas

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




disable
condition



A
method
for
disabling
the
sources
contained
by
the
specified
areas

The
corresponding
OPC
method
is
IOPCEventServer

DisableConditionByArea






Member

Description



areas

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




Browse
areas

get
root








Client

Client


DAIS

AlarmsAndEvents

Area

IHome

DAIS

AlarmsAndEvents

Area

IHome


DAIS

Node

Iterator
DAIS

Node

IteratorGet
the
root
of
all
areas
find
by
parent



next
n



Repeat
find
by
parent
and
next
n
until
the
areas
are
explored

Figure
5-9
Browse
areas
interaction















A
source
is
a
specialization
of
a
node
and
is
contained
by
areas

A
source
represents
an
object
that
generates
alarms
and
events

A
source
may
have
source
conditions

The
find
methods
in
the
interface
correspond
to
the
IOPCEventAreaBrowser
with
the
filter
type
parameter
set
to
OPC
SOURCE

The
interface
also
implements
the
following
OPC
methods




•

IOPCEventServer

TranslateToItemIDs



•

IOPCEventServer

EnableConditionBySource





•

IOPCEventServer

DisableConditionBySource






DAIS

Node

IHome

from
DAISNode

<<Interface>>
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids


DAIS

AlarmsAndEvents

Source

IHome
<<Interface>>
translate
to
item
ids


enable
conditions


disable
conditions


Source
0

n
1
0

n10

n
1
0

n1Area

from
DAI
SAEArea

AreaSourceComponent

from
DAI
SAEArea

id


ResourceID
name


string
description


string
0

n
+parent
0

n


SourceCondition

from
DAISAESo
urceCon
di
tion

condition
op
state


DAISConditionOpState
quality


DAIS

Quality
last
acknowledge


DateTime
condition
last
active


DateTime
condition
space
last
active


DateTime
condition
space
last
inactive


DateTime
acknowledger
name


string
comment


string

Figure
5-10
DAIS
alarms
and
events
source
IDL
in
UML










File

DAISAESource
idl
#ifndef


DAIS
AESOURCE
IDL
#define


DAIS
AESOURCE
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
Source
{

interface
IHome


Node

IHome
{
exception
PropertyDidNotTranslate{string
reason
}


ItemIDs
translate
to
item
ids

in
ResourceID
source
in
ResourceID
category
in
PropertyIDs
properties


raises

PropertyDidNotTranslate



ResourceErrors
enable
conditions

in
ResourceIDs
sources


ResourceErrors
disable
conditions

in
ResourceIDs
sources



}
}
}
}

#endif





DAIS
AESOURCE
IDL

IHome

An
object
for
browsing
sources
at
areas


PropertyDidNotTranslate

An
exception
telling
that
one
or
more
properties
did
not
translate
to
ItemIDs


translate
to
item
ids



A
method
for
translation
of
information
about
a
source
to
ItemIDs
for
use
with
the
data
access
interface

If
one
or
more
properties
did
not
translate
to
ItemIDs

an
exception
is
raised

The
corresponding
OPC
method
is
IOPCEventServer

TranslateToItemIDs






Member

Description



source

The
identification
of
the
source




category

The
identification
of
the
category




properties

A
sequence
of
properties
for
which
ItemIDs
are
wanted




return

A
sequence
of
ItemIDs

Properties
that
did
not
translate
to
ItemIDs
are
returned
as
empty
ItemIDs




enable
conditions



A
method
for
enabling
the
specified
sources

The
corresponding
OPC
method
is
IOPCEventServer

EnableConditionBySource






Member

Description



sources

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed




disable
conditions



A
method
for
disabling
specified
sources

The
corresponding
OPC
method
is
IOPCEventServer

DisableConditionBySource






Member

Description



sources

A
sequence
of
area
identifications




return

The
resource
identifications
that
failed



Browse
sources





Client

Client


DAIS

AlarmsAndEvents

Source

IHome

DAIS

AlarmsAndEvents

Source

IHome


DAIS

Node

Iterator
DAIS

Node

Iteratorfind
by
parent



Get
all
sources
that
has
a
given
area
as
parent
next
n



Repeat
getting
all
found
sources
from
the
iterator
and
continue
with
another
area
as
parent
to
sources

Repeat
this
until
all
wanted
sources
are
explored

For
each
source
inspect
the
conditions
it
might
have

refer
to
ConditionSpace

Figure
5-11
Browse
sources
interaction















A
condition
space
describes
a
set
of
conditions

that
is

it
is
a
space
of
conditions

Each
condition
space
is
associated
with
a
particular
sub-reason
of
the
main
reason
ConditionReason

Each
condition
has
logic
describing
when
the
condition
is
active

The
logic
is
described
in
a
little
language
having
the
following
constructs




•

arithmetic
operators



•

logic
operators



•

references
to
properties



The
referred
properties
must
be
included
in
the
set
of
properties
defined
by
the
associated
reason

The
little
language
grammar
is
server
specific
and
is
outside
the
scope
of
this
specification

Transitions
describe
what
transitions
between
conditions
are
allowed

The
interface
does
not
support
exploration
of
the
transitions


In
OPC
the
ConditionSpace
interface
is
implemented
by
the
methods




•

IOPCEventServer

QueryConditionNames





•

IOPCEventServer

QuerySubConditionNames










DAIS

AlarmsAndEvents

ConditionSpace

IHome
<<Interface>>
find


find
each


find
by
reason


find
by
source


get
names


get
ids


11


0

0
n
n



1

1
n
n


11



ConditionSpace
id


ResourceID
name


string
description


string
Condition
id
number


unsigned
long
name


string
description


string
severity


unsigned
long
condition
logic


string



ConditionCategory

from
DAISAECategory




1

1
n
n

+conditions



0

0
n
n



0

n0

n



Transition



11


11


0

0
n
n




ConditionEvent


from
DAISAEIO


Figure
5-12
DAIS
alarms
and
events
condition
space
IDL
in
UML










File

DAISAEConditionSpace
idl
#ifndef

DAIS
AECONDITION
SPACE
IDL
#define

DAIS
AECONDITION
SPACE
IDL
#pragma
prefix
"omg
org"
#include
<DAISAECommon
idl>

module
DAIS
{module
AlarmsAndEvents
{module
ConditionSpace
{
struct
ConditionDescription
{




unsigned
long

id
number





string

name





string

condition
logic





unsigned
long

severity





string

descrip




}






typedef
sequence<ConditionDescription>
ConditionDescriptions


struct
Description

{

ResourceID
id


string
name


string
descrip


ConditionDescriptionsconditions

}

typedef
sequence<
Description
>Descriptions


interface
IHome
{

exception
UnknownResourceID
{string
reason
}


Description
find


in
ResourceID
condition
space


raises

UnknownResourceID



Descriptions
find
each


in
ResourceIDs
condition
spaces


raises

UnknownResourceID



Descriptions
find
by
category


in
ResourceID
category


raises

UnknownResourceID



Descriptions
find
by
source


in
ResourceID
source


raises

UnknownResourceID



Strings
get
names


in
ResourceIDs
condition
spaces




ResourceIDs
get
ids


in
Strings
names




}
}
}
}
#endif




DAIS
AECONDITION
SPACE
IDL
ConditionDescription

A
struct
describing
a
condition




Member

Description



id
number

A
numeric
identification
unique
within
the
condition
space




name

The
name
of
the
condition




condition
logic


The
logic
telling
when
the
condition
is
active

Refer
to
Section
5
2
7
3

“Condition
Logic
?
on
page
5-38
for
a
description





severity

Severity
is
a
number
between
1
and
1000
having
the
following
meaning

•
Low
severity
1-200
•
Medium
low
severity
201-400
•
Medium
severity
401-600
•
Medium
high
severity
601-800
•
High
severity
801-1000



description

A
text
that
to
be
included
in
event
notifications
when
the
condition
is
active




Description

A
struct
describing
the
condition
space




Member

Description



id

A
ResourceID
identifying
the
condition
space




name

The
name
of
the
condition
space




description

A
description
of
the
condition
space




conditions

A
sequence
of
the
conditions
creates
the
condition
space

In
OPC
the
conditions
are
called
sub-conditions
and
are
retrieved
by
the
method
IOPCEventServer

QuerySubConditionNames






IHome

An
object
for
browsing
the
condition
spaces
defined
by
a
server


find



A
method
for
getting
the
description
of
a
condition
space




Parameter

Description



condition
space

A
ResourceID
identifying
a
condition
space




return

The
condition
space
description




find
each



A
method
for
getting
the
descriptions
for
a
number
of
condition
spaces




Parameter

Description



condition
spaces

A
sequence
of
ResourceID
identifying
condition
spaces




return

A
sequence
of
condition
space
descriptions




find
by
category



A
method
for
finding
all
condition
spaces
defined
for
a
category

The
corresponding
OPC
method
is
IOPCEventServer

QueryConditionNames






Parameter

Description



category

A
ResourceID
identifying
the
category
for
which
to
get
the
condition
spaces




return

A
sequence
of
condition
space
descriptions




find
by
source



A
method
for
finding
all
condition
spaces
defined
for
a
source

The
corresponding
OPC
method
is
IOPCEventServer

QuerySourceConditions






Parameter

Description



source

A
ResourceID
identifying
the
source
for
which
to
get
the
condition
spaces




return

A
sequence
of
condition
space
descriptions




get
names



A
method
translating
a
number
of
condition
space
identifications
into
name
strings




Parameter

Description



condition
spaces

A
sequence
of
ResourceID
identifying
condition
spaces




return

A
sequence
of
condition
space
names

Non-translated
identifications
are
returned
as
empty
strings




get
ids



A
method
translating
a
number
of
condition
space
names
into
ResourceIDs




Parameter

Description



names

A
sequence
of
condition
space
names




return

A
sequence
of
condition
space
ResourceIDs

Non-
translated
identifications
are
returned
as
NULL
IDs



Browse
condition
space
by
source





Client

Client


DAIS

AlarmsAndEvents

ConditionSpace

IHome

DAIS

AlarmsAndEvents

ConditionSpace

IHomefind
by
source



Get
all
condition
space
descriptions
for
one
source

Explore
each
condition
space
from
the
retrieved
descriptions

Figure
5-13
Browse
condition
space
by
source
interaction

Browse
condition
space
by
category





Client

CliAlrmsAndEvents

ConditionSpace

IHomeAent


DAIS

a

DAIS

larmsAndEvents

ConditionSpace

IHome
find
by
category






Get
all
condition
space
description
for
one
category

Explore
each
condition
space
from
the
retrieved
descriptions


Figure
5-14
Browse
condition
space
by
category
interaction







The
reduced
XPath
language
as
defined
in
Section
3
1
12

“Logical
Expressions
and

Navigation
?
on
page
3-25
is
used
to
describe
the
condition
logic

This
allows

description
of
a
path
through
a
data
structure
picking
up
property
values
to
be
used
in
a
logical
expression


A
common
case
is
property
values
at
objects
associated
with
a
source

hence
the
starting
point
for
navigation
is
the
source

An
example
from
the
CIM
model
where
the

Measurement
is
the
source
can
be
found
in
Figure
4-3
on
page
4-6



Examples
how
to
use
DAIS
Expressions
starting
from
a
source
are
shown
below


Measurement
value
<
500
assuming
that
the
tested
value
is
an
element
at
the
source


MeasurementValue[id
MeasurementValue
MeasurementValueSource

label='telemetry']

MeasurementValue
value
<
id
Measurement
LimitSets
[LimitSet
label
=
'summer']
Limit[label
=
'highalarm']
Limit
value


Based
on
the
model
in
Figure
4-3
on
page
4-6

the
XML
example
in
Section
3
1
12


“Logical
Expressions
and
Navigation
?
on
page
3-25
and
the
source
as
a
Measurement



















A
source
condition
associates
a
source
with
a
condition
space

A
source
condition
holds
the
current
information
specific
to
a
source
using
a
particular
condition
space
for
the
supervision

A
source
condition
has
no
own
identification
and
is
identified
by
its
associated
source
and
condition
space

Information
about
a
source
condition
is
accessed
through
its
home
object

In
OPC
a
source
condition
is
sometimes
called
an
instance
of
a
condition


In
OPC
the
SourceCondition
interface
is
implemented
by
the
methods




•

IOPCEventServer

QuerySourceConditions





•

IOPCEventServer

AckCondition











DAIS

AlarmsAndEvents

SourceCondition

IHome
<<Interface>>
find


find
each


ack
condition





Source

from
DAISAE
Source



11


0

0
n
n


11


0

0
n
n



0

0
n
n


11



11



ConditionSpace

from
DAISAE
Condi
ti
onSpace

id


ResourceID
name


string
description


string
Condition

from
DA
ISAECondi
ti
onSpace

id
number


unsigned
long
name


string
description


string
severity


unsigned
long
condition
logic


string
SourceCondition
condition
op
state


DAISConditionOpState
quality


DAIS

Quality
last
acknowledge


DateTime
condition
last
active


DateTime
condition
space
last
active


DateTime
condition
space
last
inactive


DateTime
acknowledger
name


string
comment


string
0

0
n
+active
condition

n
Figure
5-15
DAIS
alarms
and
events
source
condition
IDL
in
UML










File

DAISAESourceCondition
idl
#ifndef

DAIS
AESOURCE
CONDITION
IDL
#define

DAIS
AESOURCE
CONDITION
IDL
#pragma
prefix
"omg
org"
#include
<DAISAECommon
idl>

module
DAIS
{
module
AlarmsAndEvents
{
module
SourceCondition
{

struct
Id
{




ResourceID

source





ResourceID

condition
space




}






typedef
sequence<Id>Ids


struct
Description
{

Id
source
condition
SourceConditionOpState
source
condition
op
state
unsigned
long
active
condition
string
ac
logic
unsigned
long
ac
severity
string
ac
description
Quality
dais
quality
DateTime
last
acknowledge
DateTime
condition
last
active
DateTime
condition
space
last
active
DateTime
condition
space
last
inactive
string
acknowledger
name
string
comment
PropertyValues
property
values

}
typedef
sequence<
Description
>
Descriptions

struct
AcknowledgeSpec
{
Id
source
condition

DateTime
active
time

EventID
cookie


}

typedef
sequence<AcknowledgeSpec>AcknowledgeSpecs


interface
Iterator
{
boolean
next
n






in

unsigned
long

n





out

Descriptions

c
descriptions












void
reset



Iterator
clone



void
destroy




}


interface
IHome

{
exception
UnknownId
{string
reason
}

exception
UnknownPropertyID
{string
reason
}


Description
find


in
Id
source
condition

in
PropertyIDs
properties



raises

UnknownId

UnknownPropertyID



Iterator
find
each

in
Ids
source
conditions

in
PropertyIDs
properties



raises

UnknownId

UnknownPropertyID



Descriptions
ack
condition


#endif




DAIS
AESOURCE
CONDITION
IDL
Id




in
string

acknowledger
name





in
string

comment





in
AcknowledgeSpecs
ack
spec











}






}
}
}






A
struct
that
identifies
a
source
condition




Member

Description



source

The
ResourceID
identifying
the
associated
source




condition
space

The
ResourceID
identifying
the
associated
condition
space




Description

A
struct
describing
the
source
condition




Member

Description



id

The
Id
identifying
the
source
condition




source
condition
op
state

The
DAISSourceConditionOpState
as
described
in
Section
5
2
2

“Alarms
and
Events
Common
IDL
Definitions
?
on
page
5-7




active
condition

The
identification
number
of
the
currently
active
condition




ac
logic

The
condition
logic
from
the
active
condition




ac
severity

The
severity
from
the
active
condition




ac
description

The
description
from
the
active
condition




dais
quality

The
quality
is
evaluated
from
the
qualities
from
the
properties
used
to
evaluate
the
condition
logic




last
acknowledge

The
last
time
the
condition
was
acknowledged




condition
last
active

Time
for
the
latest
condition
transition






condition
space
last
active

The
last
time
when
the
condition
space
became
active

After
this
time
more
condition
transitions
may
occur

The
condition
last
active
will
then
be
later
than
condition
space
last
active




condition
space
last
inactive

The
last
time
when
the
condition
space
became
inactive

that
is

no
conditions
are
active




acknowledger
name

The
name
of
the
client
making
an
acknowledge




comment

A
comment
passed
by
the
client
making
an
acknowledge




property
values

A
sequence
of
property
values
as
selected
by
the
Manager

select
returned
properties
call




AcknowledgeSpec

A
struct
specifying
an
alarm
to
acknowledge




Member

Description



source
condition

The
Id
identifying
the
source
condition
for
which
to
acknowledge
an
alarm




active
time

The
time
when
the
alarm
activated




cookie

A
identification
of
the
alarm




Iterator

A
standard
iterator

Refer
to
Section
3
1
6

“Iterator
Methods
IDL
?
on
page
3-10


IHome

An
object
for
browsing
and
accessing
source
conditions


UnknownDAISSourceConditionID

An
exception
telling
that
the
source
condition
identification
was
not
recognized


UnknownPropertyID

An
exception
telling
that
a
property
identification
was
not
recognized


find



A
method
for
getting
the
description
of
a
source
condition

The
corresponding
OPC
method
is
IOPCEventServer

GetConditionState






Parameter

Description



source
condition

A
ResourceID
identifying
a
source
condition




return

The
source
condition
description




find
each



A
method
for
getting
the
descriptions
for
a
number
of
source
conditions




Parameter

Description



condition
spaces

A
sequence
identifying
source
conditions




return

A
sequence
of
source
condition
descriptions




ack
condition



A
method
to
acknowledge
a
number
of
source
condition
alarms

The
corresponding
OPC
method
is
IOPCEventServer

AckCondition






Parameter

Description



acknowledger
name

The
name
of
the
client
making
the
acknowledge




comment

A
comment
to
be
added
to
source
condition
and
the
event




ack
spec

A
sequence
specifying
the
alarms
to
acknowledge




return

A
sequence
containing
descriptions
for
the
acknowledged
source
conditions



Inspect
a
specific
source
condition





Client

Client


D
A
IS



AlarmsA
ndEvent
s

S
ourc
eC
ondition


IH
ome
DAIS

AlarmsAndEvents

SourceCondition

IHomefind



Get
all
det
ails
on
a
s
pec
ific
source
c
ondit
on

Figure
5-16
Inspect
a
specific
source
condition
interaction

Acknowledge
alarm





Client

Client


DAIS

AlarmsAndEvents

SourceCondition

IHom
e
DAIS

AlarmsAndEvents

SourceCondition

IHomeack
condition



Acknolwedge
a
set
of
source
conditions
in
one
call

Figure
5-17
Acknowledge
alarm
interaction









These
are
definitions
for
manipulating
categories

A
category
describes
the
content
of
an
event

Categories
are
organized
in
a
two
level
hierarchy
where
the
first
level
has
the
three
mandatory
main
categories

simple

condition

and
tracking


Simple
category
does
not
have
a
condition
space

refer
to
ConditonSpace


Generation
of
simple
category
alarms
or
events
is
coded
into
some
software
function
and
cannot
be
configured

Typical
simple
categories
are
program
errors

hardware
device
failures

etc


Sources
of
different
types

e
g


breaker
position

breaker
current

generator
active
power

etc


may
have
different
ways
an
alarm
or
event
is
generated

e
g


breaker
trip

breaker
over
current

generator
active
power
generation
overload

etc



Condition
categories
are
used
to
describe
source
type
specific
alarm
and
event
contents


The
alarm
and
event
generation
for
a
condition
category
is
configured
using
condition
spaces
and
several
condition
spaces
can
be
created
for
the
same
condition
category

This
corresponds
to
variations
in
the
way
the
alarms
and
events
are
generated
using
different
condition
logics


Alarms
or
events
due
to
operator
actions
or
control
functions

intended
alarms
or
events
rather
than
spontaneous

use
tracking
categories


A
category
has
a
set
of
properties
associated
with
it

Some
or
all
of
the
properties
may
be
included
in
event
notifications

The
properties
come
from
the
source
type
and
may
be
used
by
the
logic
generating
an
event
notification


The
get
main

category



method
is
used
to
obtain
the
three
main
categories

The
find
by
parent


is
used
to
get
the
child
categories

Categories
at
this
second
level
correspond
to
the
OPC
EventCategories

The
labels
for
the
three
main
reasons
are
“DAIS
CONDITION
CATEGORY
?
“DAIS
TRACKING
CATEGORY
?
and
"DAIS
SIMPLE
CATEGORY
?

In
OPC
the
Category
interface
is
implemented
by
the
methods
IOPCEventServer

QueryEventCategories


and
IOPCEventServer

QueryEventAttributes






TrackingCategory
SimpleCategory
ConditionCategory
DAIS

AlarmsAndEvents

Category

IHome
get
main
categories


get
event
properties


<<Interface>>
DAIS

Node

IHome
find


find
each


find
by
parent


find
by
type


get
pathnames


get
ids



from
DAISNode

<<Interface>>
Node
id


ResourceID
label


string
type


ResourceID

f
rom
DA
ISNo
de

1
0

10

nCategory

Figure
5-18
DAIS
alarms
and
events
categories
IDL
in
UML











File

DAISAECategory
idl
#ifndef

DAIS
AECATEGORY
IDL
#define

DAIS
AECATEGORY
IDL
#pragma
prefix
"omg
org"
#include
<DAISNode
idl>

module
DAIS
{module
AlarmsAndEvents
{module
Category{
interface
IHome


Node

IHome
{
Node

Descriptions
get
main
categories





PropertyIDs
get
event
properties

in
ResourceID
category



}

}
}
}

#endif




DAIS
AECATEGORY
IDL

IHome

IHome
is
an
object
for
browsing
categories

Most
of
the
browsing
functionality
is
inherited
from
DAIS

Node


get
main
categories



Get
the
three
main
categories

simple

condition

and
tracking

The
three
main
categories
appear
as
three
different
roots


Parameter
Description

return

The
descriptions
for
the
three
main
categories

The
labels
for
them
are




•

“DAIS
CONDITION
CATEGORY?



•

“DAIS
TRACKING
CATEGORY?



•

“DAIS
SIMPLE
CATEGORY?



get
event
properties



Get
all
properties
that
are
used
in
the
supervision
of
the
source
type
for
a
specific
category

The
corresponding
OPC
method
is
IOPCEventServer

QueryEventAttributes






Parameter

Description



category

The
identification
of
the
categories
to
get
the
properties
for




return

A
sequence
of
property
identifications




Browse
categories

get
main
reasons








DAIS

AlarmsAndEvents

Category

IHome
DAIS

AlarmsAndEvents

Category

IHome

Client

ClientGet
the
three
main
reasons
find
by
parent



Get
the
sub
reasons
for
one
main
reason

For
each
sub
reason
explore
1

the
condition
spaces
that
are
defined

refer
to
ConditionSpace
2

the
properties
that
are
used
in
supervision
of
sources
Continue
and
explore
all
main
reasons

Figure
5-19
Browse
category
interaction
Browse
properties





DAIS

Alarm
sAndE
vents

Category

IHom
e
DAIS

AlarmsAndEvents

Category

IHome

Client

ClientGet
the
three
m
ain
categories
Get
the
sub
categories
for
one
main
category

For
each
sub
category
explore
1

the
condition
spaces
that
are
defined

refer
to
ConditionSpace
2

the
properties
that
are
used
in
supervision
of
sources
Continue
and
explore
all
main
categories

get
main
categories




find
by
parent




Figure
5-20
Browse
properties
interaction

















The
IO
interface
for
alarms
&
events
only
supports
callbacks
and
the
client
shall
implement
callback


The
event
notifications
sent
over
the
callback
are
of
three
different
formats
corresponding
to
the
three
main
categories

simple
event

condition
event

and
tracking
event


All
three
event
formats
have
the
common
part
Event

The
tracking
event
has
additional
information
on
the
operator
and
the
condition
event
has
additional
information
on
the
source
condition
causing
the
notification


In
OPC
the
IO
interface
is
implemented
by
the
interface
IOPCEventSink


Source

from
DAISAESource

Event
source


ResourceID
source
pathname


string
time
stamp


DateTime
message


string
event
format


EventFormat
category


ResourceID
category
name


string
severity


unsigned
long
property
values


PropertyValues
11SimpleCategory

from
DAISAECa
tegory

SimpleEvent
11ConditionCategory

from
DAISAECategory


ConditionEvent
condition
space
name


string
condition
space


ResourceID
condition
name


string
condition
number


unsigned
long
ack
required


boolean
active
time


DateTime
event
id


EventID
change
specification


ChangeSpec
source
condition
op
state


SourceConditionOpState
dais
quality


Quality
TrackingCategory

from
DAISAECategory


TrackingEvent
actor
name


string
11DAIS

AlarmsAndEvents

IO

Callback
<<Interface>>
on
event


on
read
complete





11

Figure
5-21
DAIS
alarms
and
events
IO
IDL
in
UML











File

DAISAEIO
idl#ifndef

DAIS
AEIO
IDL#define

DAIS
AEIO
IDL#pragma
prefix
"omg
org"#include
<DAISAECommon
idl>
module
DAIS
{module
AlarmsAndEvents
{module
IO
{
typedef
unsigned
long
ChangeSpec
const
ChangeSpec
CHANGE
ACTIVE
STATE
=
0x0001

const
ChangeSpec
CHANGE
ACK
STATE
=
0x0002

const
ChangeSpec
CHANGE
ENABLE
STATE
=
0x0004

const
ChangeSpec
CHANGE
QUALITY
=
0x0008

const
ChangeSpec
CHANGE
SEVERITY
=
0x0010

const
ChangeSpec
CHANGE
CONDITION
=
0x0020

const
ChangeSpec
CHANGE
MESSAGE
=
0x0040

const
ChangeSpec
CHANGE
ATTRIBUTE
=
0x0080


struct
SimpleEvent
{
ResourceID
source

string
source
pathname

DateTime
time
stamp

string
message

EventFormat
event
format

ResourceID
category

string
category
name

unsigned
long
severity

PropertyValues
property
values


}


struct
TrackingEvent
{
string
actor
name

}


struct
ConditionEvent
{
string
condition
space
name

ResourceID
condition
space

string
condition
name

unsigned
long
condition
number

boolean
ack
required

DateTime
active
time

EventID
event
id

ChangeSpec
change
specification

SourceConditionOpState
source
condition
op
state

Quality
dais
quality


}


struct
Event
{
SimpleEvent
simple
event

TrackingEvent
tracking
event

ConditionEvent
condition
event


}
typedef
sequence<Event>
Events

interface
Callback{
void
on
event

in
boolean
refresh
in
boolean
last
refresh
in
Events
the
events




void
on
read
complete

in
Events
the
events
in
unsigned
long
transaction
id



}

}
}
}

#endif




DAIS
AEIO
IDL

ChangeSpec

A
flag
word
having
a
number
of
flags
telling
what
change
caused
the
event
notification




Flag

Description



CHANGE
ACTIVE
STATE

Alarm
active
has
changed




CHANGE
ACK
STATE

Alarm
acknowledge
has
changed




CHANGE
ENABLE
STATE

Enable
has
changed




CHANGE
QUALITY

The
quality
has
changed




CHANGE
SEVERITY

The
severity
has
changed




CHANGE
CONDITION

A
condition
has
become
active
inactive




CHANGE
MESSAGE

The
message
has
been
updated




CHANGE
ATTRIBUTE

An
attribute
value
has
changed




SimpleEvent

A
struct
holding
the
simple
event
data




Member

Description



source

The
identification
of
the
source
for
which
the
event
notification
was
created




source
pathname

The
full
pathname
of
the
source




time
stamp

Time
of
the
event
occurrence
-
for
conditions

time
that
the
condition
transitioned
into
the
new
state
or
condition


For
example

if
the
event
notification
is
for
acknowledgment
of
a
condition

this
would
be
the
time
that
the
condition
became
acknowledged




message

Event
notification
message
describing
the
event




event
format

The
identification
for
one
of
the
three
main
formats






category

The
identification
of
the
sub-category
why
the
event
notification
was
sent




category
name

The
label
for
the
sub-category




severity

The
severity
for
the
event

a
number
between
0
and
1000




property
values

A
sequence
of
property
values
as
selected
by
the
select
returned
properties


method




TrackingEvent

A
struct
holding
tracking
event
data




Member

Description



actor
name

The
name
of
the
actor
or
operator
causing
the
event




notification




ConditionEvent

A
struct
holding
the
condition
event
data




Member

Description



condition
space
name

The
name
of
the
condition
space
that
caused
the
event
notification




condition
space

Identification
of
the
condition
space




condition
name

The
name
of
the
condition
that
caused
the
event
notification




condition
number

Identification
of
the
condition




ack
required

An
indication
that
an
alarm
is
generated
and
that
an
acknowledgment
is
required




active
time

The
time
when
the
condition
became
active




event
id

An
identification
of
the
event
notification




change
specification

Indicates
to
the
client
which
properties
of
the
condition
have
changed




source
condition
op
state

The
new
state
for
the
source
condition




quality

The
quality




Event

A
struct
composed
of
the
three
above
event
structs

The
simple
event
struct
always
contains
valid
information
and
which
of
the
tracking
or
condition
event
structs
are
valid
is
decided
from
the
main
reason
simple
event
member




Member

Description



simple
event

The
simple
event




tracking
event

The
tracking
event




condition
event

The
condition
event




Callback

The
callback
object
implemented
by
the
client
and
used
by
the
server
to
send
event
notifications


on
event



The
callback
method




Parameter

Description



refresh

Indicates
if
this
callback
is
due
to
a
refresh




last
refresh

Indicates
if
this
callback
is
the
last
in
a
sequence
initiated
by
a
refresh




the
events

A
sequence
of
event
notifications




return

None




on
read
complete



A
callback
method
for
the
async
read
history


method

After
an
async
read
history


call
from
a
client
the
server
will
deliver
the
historical
events
using
this
method

There
is
no
corresponding
OPC
method




Parameter

Description



the
events

A
sequence
of
historical
events




transaction
id

The
transaction
number
matching
the
client
call
number




Event
notification
callbacks





DAIS

Alarm
sAndEvents

IO

Callback

DAIS

AlarmsAndEvents

Ints
Subscription

M
anagerntO

Callback

DAIS

AlarmsAndEve


DAIS

AlarmsAndEves

Subscription

Manageron
event



on
event



The
on
event
method
is
called
by
the
server
at
1

expiration
of
the
subscription
buffer
time
timeout
2

subscription
event
buffer
full
For
alarms
the
client
may
want
to
call
SourceCondition

ack
alarm


to
acknowledge

A
ll
inform
ation
needed
for
doing
this
is
found
in
the
event
notifications

Figure
5-22
Event
notification
callbacks
interaction

Refresh
callbacks





DAIS

AlarmsAndEvents

IO

Callback

DAIS

AlarmsAndEvents

IO

CallbackOn
event
is
called
as
response
to
a
refresh

All
refresh
calls
are
made
with
the
refresh
parameter
set
and
the
last
call
also
has
the
last
refresh
parameter
set



DAIS

AlarmsAndEvents

Subscription

Manager
DAIS

AlarmsAndEvents

Subscription

Manageron
event




Figure
5-23
Refresh
callbacks
interaction