In Figure 2, illustrates the 3:AnalogSignalVariableType and the ProcessValueSetpointVariableType and their supertypes with key InstanceDeclarations. The 3:AnalogSignalVariableType provides the optional Properties 0:ValuePrecision and 0:InstrumentRange and the mandatory Properties 0:EURange and 0:EngineeringUnits and are used as defined in OPC 10000-8. They provide information about the precision, ranges and unit of the process value. The optional Variables 3:ActualValue, 3:SimulationValue, and 3:SimulationState are used as defined in OPC 30081 and provide a simulation value and a flag to define, which value is used.
The ProcessValueSetpointVariableType defined in 9.1 adds additional, optional meta data.
