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.
It is an indication of whether or not the physical input that the object represents is not in service. While Out_Of_Service is True, Present_Value and Reliability may be changed to any value as a means of simulation and/or testing.
It shall specify the minimum change in the BACnet property Present_Value that will cause a Change of Value notification to be issued to BACnet clients that have subscribed to Change of Value events.
It indicates the smallest recognizable change in Present_Value in engineering units.
The EventReporting Object contains status and configuration information for the event reporting of BACnetAnalogTypes and their subtypes. The BACnetEventReportingType is defined in 8.8. The Object is optional and is not present if event generation is not activated for the BACnet object.
The EventAlgorithm component is changed to TypeDefinition BACnetOutOfRangeAlgorithmType and ModellingRule Mandatory if used in the BACnetAnalogType or one of its subtypes. The BACnetOutOfRangeAlgorithmType is defined in 8.9.3.
On the EventAlgorithm instance of the BACnetOutOfRangeAlgorithmType the BACnet property High_Limit is mapped to pHighLimit, the BACnet property Low_Limit is mapped to LowLimit, the BACnet property Deadband is mapped to pDeadband and the BACnet property Limit_Enable is mapped to LimitEnable.
The FaultEvaluation Object contains status and configuration information for the fault evaluation of the BACnetAnalogType. The BACnetFaultEvaluationType is defined in 8.23. The Object is optional and is not present if fault evaluation is not activated for the BACnet object.