The Quality of a Data Value in the OPC UA Server is represented as a StatusCode.
The COM UA Proxy maps the Severity, Subcode and the limit bits of the OPC UA Status code to the lower 8 bits of the OPC DA Quality structure (of the form QQSSSSLL). Figure A.6 illustrates this mapping.
Figure A.6 – OPC UA Status Code to OPC DA quality mapping
The Severity field of the Status code is mapped to the primary quality. The SubCode is mapped to the Sub Status and the Limit Bits are mapped to the Limit field.
Table A.7 shows a mapping of the OPC UA status code to OPC DA primary quality
|
OPC UA Status Code |
OPC DA Primary Quality (Quality & Sub status QQSSSS) |
|
Good |
GOOD |
|
Good_LocalOverride |
LOCAL_OVERRIDE |
|
Uncertain |
UNCERTAIN |
|
Uncertain_SubNormal |
SUB_NORMAL |
|
Uncertain_SensorNotAccurate |
SENSOR_CAL |
|
Uncertain_EngineeringUnitsExceeded |
EGU_EXCEEDED |
|
Uncertain_LastUsableValue |
LAST_USABLE |
|
Bad |
BAD |
|
Bad_ConfigurationError |
CONFIG_ERROR |
|
Bad_NotConnected |
NOT_CONNECTED |
|
Bad_NoCommunication |
COMM_FAILURE |
|
Bad_OutOfService |
OUT_OF_SERVICE |
|
Bad_DeviceFailure |
DEVICE_FAILURE |
|
Bad_SensorFailure |
SENSOR_FAILURE |
|
Bad_WaitingForInitialData |
WAITING_FOR_INITIAL_DATA |