The TwoStateDiscreteSignalVariableType is used for process variables, that can have two states, and illustrated in Figure 12. It is formally defined in Table 190.

Table 190 – TwoStateDiscreteSignalVariableType definition

Attribute

Value

BrowseName

TwoStateDiscreteSignalVariableType

IsAbstract

False

ValueRank

−2 (−2 = ‘Any’)

DataType

Boolean

References

NodeClass

BrowseName

DataType

TypeDefinition

Other

Subtype of 0:TwoStateDiscreteType defined in OPC 10000-8, i.e. inheriting the InstanceDeclarations of that Node

0:HasComponent

Variable

ActualValue

0:Boolean{Any}

0:BaseDataVariableType

O

0:HasComponent

Variable

SimulationValue

0:Boolean{Any}

0:BaseDataVariableType

O

0:HasComponent

Variable

SimulationState

0:Boolean

0:BaseDataVariableType

O

0:HasDictionaryEntry

Object

3:0112/2///61987#ABN635#001

0:IrdiDictionaryEntryType

Conformance Units

PA-DIM TwoStateDiscreteVariable

PA-DIM TwoStateDiscreteVariable Simulation

ActualValue: ABN645#001 defines parameter indicating the binary value of a not simulated binary process variable of a device.

SimulationValue: ABN632#001 parameter indicating the simulated value of a binary variable.

SimulationState is defined by IRDI as ABN611#001 which 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’.

ABN635#001 defines parameter indicating the binary input or output value of a device.

The components of TwoStateDiscreteSignalVariableType have additional references which are defined in Table 191.

Table 191 – TwoStateDiscreteSignalVariableType additional References

SourceBrowsePath

Reference Type

Is Forward

TargetBrowsePath

ActualValue

0:HasDictionaryEntry

True

3:0112/2///61987#ABN645#001

SimulationValue

0:HasDictionaryEntry

True

3:0112/2///61987#ABN632#001

SimulationState

0:HasDictionaryEntry

True

3:0112/2///61987#ABN611#001

The child Nodes of the TwoStateDiscreteSignalVariableType have additional Attribute values defined in Table 192.

Table 192 – TwoStateDiscreteSignalVariableType Attribute values for child Nodes

BrowsePath

Value Attribute

ActualValue

False

SimulationValue

False

SimulationState

False