7.3.2 Operation level result codes

Certain conditions under which a Variable value was generated are only valid for automation data and in particular for device data; they are similar, but are slightly more generic than the description of data quality in the various fieldbus specifications.

Table 61 contains codes with BAD severity which indicates a failure.

Table 62 contains codes with UNCERTAIN severity which indicates that the value has been generated under sub-normal conditions.

Table 63 contains GOOD (success) codes.

Note again, that these are the codes that are specific for Data Access and supplement the codes that apply to all types of data which are defined in OPC 10000-4.

Table 61 – Operation level result codes for BAD data quality
Symbolic Id Description
BadDefined in OPC 10000-4. It shall be used when there is no special reason why the Value is bad.
Bad_ConfigurationErrorThere is a problem with the configuration that affects the usefulness of the value.
Bad_NotConnectedThe variable should receive its value from some data source, but has never been configured to do so.
Bad_DeviceFailureThere has been a failure in the device/data source that generates the value that has affected the value.
Bad_SensorFailureThere has been a failure in the sensor from which the value is derived by the device/data source.
The limits bits are used to define if the limits of the value have been reached.
Bad_NoCommunicationDefined in OPC 10000-4. It shall be used when communications to the data source is defined, but not established, and there is no last known value available.
Bad_OutOfServiceThe source of the data is not operational.
Bad_LastKnownOPC UA requires that the Server shall return a Null value when the Severity is Bad. Therefore, the Fieldbus code “Bad_LastKnown” shall be mapped to Uncertain_NoCommunicationLastUsable.
Bad_DeadbandFilterInvalidThe specified PercentDeadband is not between 0.0 and 100.0 or a PercentDeadband is not supported, since an EURange is not configured.
Bad_WaitingForInitialDataDefined in OPC 10000-4
Table 62 – Operation level result codes for UNCERTAIN data quality
Symbolic Id Description
UncertainDefined in OPC 10000-4. It shall be used when there is no special reason why the Value is uncertain.
Uncertain_ NoCommunicationLastUsable

Communication to the data source has failed. The variable value is the last value that had a good quality and it is uncertain whether this value is still current.

The server timestamp in this case is the last time that the communication status was checked. The time at which the value was last verified to be true is no longer available.

Uncertain_LastUsableValue

Whatever was updating this value has stopped doing so. This happens when an input variable is configured to receive its value from another variable and this configuration is cleared after one or more values have been received.

This status/substatus is not used to indicate that a value is stale. Stale data can be detected by the client looking at the timestamps.

Uncertain_SubstituteValueThe value is an operational value that was manually overwritten.
Uncertain_InitialValueThe value is an initial value for a variable that normally receives its value from another variable. This status/substatus is set only during configuration while the variable is not operational (while it is out-of-service).
Uncertain_SensorNotAccurateThe value is at one of the sensor limits. The Limits bits define which limit has been reached. Also set if the device can determine that the sensor has reduced accuracy (e.g. degraded analyzer), in which case the Limits bits indicate that the value is not limited.
Uncertain_ EngineeringUnitsExceededThe value is outside of the range of values defined for this parameter. The Limits bits indicate which limit has been reached or exceeded.
Uncertain_SubNormal The value is derived from multiple sources and has less than the required number of Good sources.
Uncertain_SimulatedValueThe value is simulated.
Uncertain_SensorCalibrationThe value possibly is not accurate due to a sensor calibration fault.
Uncertain_ConfigurationErrorThe value possibly is not accurate due to a configuration issue.
Table 63 – Operation level result codes for GOOD data quality
Symbolic IdDescription
GoodDefined in OPC 10000-4. It shall be used when there are no special conditions.
Good_LocalOverrideThe value has been Overridden. Typically, this means the input has been disconnected and a manually-entered value has been "forced".