Data Quality and NULL Handling

The Historian SDK interface requires that the OPC quality is provided for every value to be stored. The OPC quality should be equal to 192 (good) if the value is considered to be reliable.

If the Historian SDK application plays the role of an intermediate data collector, such as one receiving data values from some I/O Server that can connect and disconnect from the SDK application by itself, it is recommended to store values of OPC quality of 24 to indicate such disconnects, if necessary.

You can insert or update NULL values for original non-streamed data by setting the OpcQuality property value of the HistorianDataValue instance to 0. At retrieval time, that data value will have an OPC quality of 0 and a QualityDetail of 249.

For more information on data quality, see the AVEVA Historian Concepts Guide.