A.3.2.3 Quality

The Quality of a Data Value in the DA server is represented as a 16 bit value where the lower 8 bits is of the form QQSSSSLL (Q: Main Quality, S: Sub Status, L: Limit) and higher 8 bits is vendor specific.

The COM UA Wrapper maps the DA server to the OPC UA Status code as shown in Figure A.15:

Figure A.15 – Status Code mapping

The primary quality is mapped to the Severity field of the Status code. The Sub Status is mapped to the SubCode and the Limit is mapped to the Limit Bits of the Status Code.

Please note that the Vendor quality is currently discarded.

Table A.3 shows a mapping of the OPC COM DA primary quality mapping to OPC UA status code

Table A.3 – Quality mapping
OPC DA Primary Quality (Quality & Sub status QQSSSS)OPC UA Status Code
GOODGood
LOCAL_OVERRIDE Good_LocalOverride
UNCERTAINUncertain
SUB_NORMALUncertain_SubNormal
SENSOR_CALUncertain_SensorNotAccurate
EGU_EXCEEDEDUncertain_EngineeringUnitsExceeded
LAST_USABLEUncertain_LastUsableValue
BADBad
CONFIG_ERRORBad_ConfigurationError
NOT_CONNECTEDBad_NotConnected
COMM_FAILUREBad_NoCommunication
DEVICE_FAILUREBad_DeviceFailure
SENSOR_FAILUREBad_SensorFailure
LAST_KNOWNBad_OutOfService
OUT_OF_SERVICEBad_OutOfService
WAITING_FOR_INITIAL_DATABad_WaitingForInitialData