7.4.3.1 Variable Present_Value

This OPC UA Variable, of DataType Float, indicates the current value, in engineering units, of the input being measured. The Present_Value Variable shall be writable when Out_Of_Service is true.

This OPC UA AnalogItemType Variable represents the BACnet properties Present_Value, Min_Pres_Value, Max_Pres_Value, Units and Update_Interval. The OPC UA VariableType AnalogItemType is defined in OPC 10000-8. It defines the OPC UA Properties EURange, EngineeringUnits and InstrumentRange.

The following list provides the BACnet property and the mapping to the corresponding data member in the OPC UA AnalogItem.

Present_Value represented by Value Attribute of the Variable.

Min_Pres_Value represented by Low part of EURange Property of the Variable. If the optional BACnet property Min_Pres_Value is not present, the EURange Property should not be provided.

Max_Pres_Value represented by the High part of EURange Property of the Variable. If the optional BACnet property Max_Pres_Value is not present, the EURange Property should not be provided.

Units represented by the EngineeringUnits Property of the Variable. The mapping of BACnet units to OPC UA units is defined in 11.

Update_Interval represented by MinSamplingInterval Attribute of the Variable.