Errata exists for this version of the document.
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 Figure A.7:
Figure A.7 - 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.33 shows a mapping of the OPC COM DA primary quality mapping to OPC UA status code
|
OPC DA Primary Quality (Quality & Sub status QQSSSS) |
OPC UA Status Code |
|
GOOD |
Good |
|
LOCAL_OVERRIDE |
Good_LocalOverride |
|
UNCERTAIN |
Uncertain |
|
SUB_NORMAL |
Uncertain_SubNormal |
|
SENSOR_CAL |
Uncertain_SensorNotAccurate |
|
EGU_EXCEEDED |
Uncertain_EngineeringUnitsExceeded |
|
LAST_USABLE |
Uncertain_LastUsableValue |
|
BAD |
Bad |
|
CONFIG_ERROR |
Bad_ConfigurationError |
|
NOT_CONNECTED |
Bad_NotConnected |
|
COMM_FAILURE |
Bad_NoCommunication |
|
DEVICE_FAILURE |
Bad_DeviceFailure |
|
SENSOR_FAILURE |
Bad_SensorFailure |
|
LAST_KNOWN |
Bad_OutOfService |
|
OUT_OF_SERVICE |
Bad_OutOfService |
|
WAITING_FOR_INITIAL_DATA |
Bad_WaitingForInitialData |