The DiscreteSignalVariableType is used for process variables of any data type, Integer, UInteger, Boolean, Structure etc. E.g. the data type Structure can be for aggregation of multiple values into one signal variable. ActualValue contains the unsimulated value during a simulation and SimulationValue contains the value to be used during simulation.
The DiscreteSignalVariableType is a subtype of the DiscreteItemType defined in OPC 10000-8 and adds optionally ActualValue and SimulationValue components. It is formally defined in Table 196.
Table 196 – DiscreteSignalVariableType definition
|
Attribute |
Value |
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|
BrowseName |
DiscreteSignalVariableType |
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|
IsAbstract |
False |
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|
ValueRank |
−2 (−2 = ‘Any’) |
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|
DataType |
BaseDataType |
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|
References |
NodeClass |
BrowseName |
DataType |
TypeDefinition |
Other |
|
Subtype of 0:DiscreteItemType defined in OPC 10000-8, i.e. inheriting the InstanceDeclarations of that Node |
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|
0:HasComponent |
Variable |
ActualValue |
0:BaseDataType{Any} |
0:BaseDataVariableType |
O |
|
0:HasComponent |
Variable |
SimulationValue |
0:BaseDataType{Any} |
0:BaseDataVariableType |
O |
|
0:HasComponent |
Variable |
SimulationState |
0:Boolean |
0:BaseDataVariableType |
O |
|
Conformance Units |
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|
PA-DIM DiscreteVariable |
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|
PA-DIM DiscreteVariable Simulation |
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ActualValue: ABN644#001 defines “parameter indicating the value of the not simulated discrete process variable of a device”.
SimulationValue: ABN613#001 defines “parameter indicating the simulated value of a variable, which can have multiple states”.
SimulationState: ABN611#001 defines “parameter indicating the state of simulation” and used also to enable/disable simulation. The value true means ‘Simulation enabled’, and false means ‘Simulation disabled’.
The components of DiscreteSignalVariableType have additional references which are defined in Table 197.
Table 197 – DiscreteSignalVariableType additional References
|
SourceBrowsePath |
Reference Type |
Is Forward |
TargetBrowsePath |
|
ActualValue |
0:HasDictionaryEntry |
True |
|
|
SimulationValue |
0:HasDictionaryEntry |
True |
|
|
SimulationState |
0:HasDictionaryEntry |
True |
The child Nodes of the DiscreteSignalVariableType have additional Attribute values defined in Table 198.
Table 198 – DiscreteSignalVariableType Attribute values for child Nodes
|
BrowsePath |
Value Attribute |
|
SimulationState |
False |