Relating DNP3 Status Flags to OPC Qualities

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ClearSCADA sets corresponding OPC quality in point objects based on ClearSCADA status (e.g. Objects in service, outstation healthy, etc) and the DNP3 object status flags.

Mapping from DNP3 status flags to OPC quality is as follows:

DNP3 Flag	OPC Quality
Online flag = 0	Bad - Out of Service
Restart flag = 1	Bad - Waiting for Initial Data
Comms Lost = 1	Bad - Comm Failure
Chatter Filter = 1	Uncertain - Sensor Cal (Binary Input)
A/D Reference Check=1	Uncertain - Sensor Cal (Analogue Input)
Overrange = 1	Uncertain - Engineering units exceeded (Analogue).
Discontinuity	Uncertain - Sensor Cal (Counter and Frozen Counter)
Local Forced	Good - Local Override*
Remote Forced = 1	Good - Local Override*
Rollover = 1	No equivalent (now deprecated in DNP3)

Multiple DNP3 flags can be asserted at the same time but only one OPC quality can be represented. SCX6 processes the flags in the order listed above and will stop processing further flags if a test succeeds.

ClearSCADA configuration for DNP3 point objects may have processing for the Override Flag disabled. (Default is Process Override Flag enabled). Disabling processing of this flag is particularly useful for Control Microsystems E-Series outstations that set the "Remote Forced" flag to indicate a point that is "under ISaGRAF control".

When a DNP3 object without status is received, it is assumed to be "Online" with no other flags set, as per the DNP3 standard. ClearSCADA indicates Good quality on these objects if all other ClearSCADA quality constraints are met.

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