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