The AnalogSignalVariableType is used for analog variables representing temperature, flow, pressure, etc.. The AnalogSignalVariableType is a subtype of the AnalogUnitRangeType and adds the optional components ActualValue, SimulationValue and Damping. The model and its subtypes are illustrated in Figure 9.
Figure 9 - AnalogSignal and Signal Object Model
The AnalogSignalVariableType can be used to model any analog signal type. It extends the AnalogUnitRangeType defined in OPC 10000-8 to add additional information such as values for simulation and damping as well as dictionary references.
The ActualValue contains the unsimulated value during a simulation and SimulationValue contains the value to be used during simulation, as illustrated in Figure 10. The Value attribute always represents what is being reported by the Variable.
AnalogSignalVariableType is formally defined in Table 24.
Table 24 - AnalogSignalVariableType
|
Attribute |
Value |
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|
BrowseName |
AnalogSignalVariableType |
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|
IsAbstract |
False |
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ValueRank |
−2 (−2 = ‘Any’) |
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|
DataType |
Number |
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|
References |
NodeClass |
BrowseName |
DataType |
TypeDefinition |
Modelling Rule |
|
Subtype of AnalogUnitRangeType defined in OPC 10000-8 |
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|
|
|
|
|
|
0:HasComponent |
Variable |
ActualValue |
0:Number{Any} |
0:BaseDataVariableType |
0:Optional |
|
0:HasComponent |
Variable |
SimulationValue |
0:Number{Any} |
0:BaseDataVariableType |
0:Optional |
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|
|
|
|
|
|
|
0:HasComponent |
Variable |
SimulationState |
0:Boolean |
0:BaseDataVariableType |
0:Optional |
|
0:HasProperty |
Variable |
Damping |
0:Float |
0:PropertyType |
0:Optional |
|
0:HasDictionaryEntry |
Object |
|
0:IrdiDictionaryEntryType |
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|
|
|
|
|
|
|
|
0:HasSubtype |
VariableType |
TemperatureMeasurementVariableType |
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|
0:HasSubtype |
VariableType |
PressureMeasurementVariableType |
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0:HasSubtype |
VariableType |
FlowMeasurementVariableType |
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|
0:HasSubtype |
VariableType |
LevelMeasurementVariableType |
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|
0:HasSubtype |
VariableType |
ActualDensityVariableType |
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0:HasSubtype |
VariableType |
ControlVariableType |
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0:HasSubtype |
VariableType |
TotalizerVariableType |
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0:HasSubtype |
VariableType |
AnalyticalMeasurementVariableType |
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AnalogSignalVariableType also extends AnalogUnitRangeType by providing additional references. These references provide dictionary entries for all of the variables defined by this addition as well as dictionary references for fields in the parent AnalogUnitRangeType. See Table 25 for a complete definition.
Table 25 - AnalogSignalVariableType Additional References
|
Source Path |
Reference Type |
Is Forward |
Target Path |
|
ActualValue |
0:HasDictionaryEntry |
0:True |
|
|
SimulationValue |
0:HasDictionaryEntry |
0:True |
|
|
Damping |
0:HasDictionaryEntry |
0:True |
|
|
SimulationState |
0:HasDictionaryEntry |
0:True |
The VariableType is extended in this definition to include the dictionary reference. The dictionary provides an additional description of Value which is copied here for clarity – “ABN634#001 defines parameter indicating the input or output value of a device using the units of measure of the process variable.”
ActualValue reflects the measured value independent of the simulation state. It is further described by dictionary entry ABN644#001 which states “defines parameter indicating the value of the not simulated process variable of a device using the units of measure of the process variable”.
SimulationValue provides a value that substitutes Value if the simulation is enabled. It is further described by dictionary entry ABN613#001 which states “defines parameter indicating the simulated value of a variable using the units of measure of the simulated variable”.
Damping provides a value that is used to flatten changes in the value. It is further described by dictionary entry ABH526#001 which states “defines for the output of a first-order system forced by a step or an impulse, the time required to complete 63.2% of the total rise or decay at any instant during the process”.
SimulationState is defined by IRDI as ABN611#001 which states “defines parameter indicating the state of simulation” and used also to enable/disable simulation.
The Property EngineeringUnits – inherited from AnalogUnitRangeType (see OPC 10000-8 Amendment 1) – shall be used to define the unit for the AnalogSignalVariableType instance and also for its ActualValue and SimulationValue component Variables.
In addition, each EngineeringUnits Property shall provide a HasDictionaryEntry reference to the IEC Common Data Dictionary entry for "unit of measure" which is 3:0112/2///61987#ABA968#002. Figure 11 illustrates this with an example.
Figure 11 - EngineeringUnits Property with HasDictionaryEntry Reference
If MultiStateDictionaryEntryDiscreteType Variables reference an IEC 61987 CDD PROPERTY with a Value list, the following mapping applies:
- For each possible element in the "Value list" map the Preferred name of the element to the „EnumValues“ Property.
- For each possible element in the "Value list" map the IRDI of the element to the „EnumDictionaryEntries“ Property.
An example for the SensorConnection Property with IRDI 0112/2///61987#ABB091#002 is in Table 26:
Table 26 - Example of a MultiStateDictionaryEntryDiscreteType with CDD reference
|
IEC 61987 CDD |
ecl@ss |
OPC UA mapping |
|
|
„Value list“ attribute |
„Value list“ attributeto be defined |
„EnumValues“ Property |
„EnumDictionaryEntries“ Property |
|
0112/2///61987#ABL113 - 4-wire |
0173-1#02-CCCnnn#00n |
[0] "4-wire" |
[0] 3:0112/2///61987#ABL113#001 |
|
0112/2///61987#ABL114 - 3-wire |
0173-1#02-CCCnnn#00n |
[1] "3-wire" |
[1] 3:0112/2///61987#ABL114#001 |
|
0112/2///61987#ABL115 - 2-wire |
0173-1#02-CCCnnn#00n |
[2] "2-wire" |
[2] 3:0112/2///61987#ABL115#001 |
|
0112/2///61987#ABI407 – others |
0173-1#02-CCCnnn#00n |
[3] "others" |
[3] 3:0112/2///61987#ABI407#004 |