Wrong Log data stored
I am using a log configuration with the following configuration:
Min Time: 490msec
Max Time 2 Sec
I am using this log for a bool-signal.
But when I see trend display and also if I read the points in the Log Configuration Aspect, that log is not reflecting the real signal.
Normally the value is stored in the log history as a Raw-Value on an event (True-> False). The other values between the events are extrapolated.
So after every 1-Raw-Signal there should be a 0-Raw-Signal.1 Raw
In my log, there are two 0-Raw-Signals in a row, and this is a fault. See print screen attached. All the yellow marked data are wrong in this storage.
Are you really sure the Value is wrong? Because the Raw Value is stored when received from the OPC Server not depending on a change, it can still happen that a new Raw Value is stored if the OPC Server does transmit it - so what you really want to say is that the OPC Server sent a Value update even if the Value didn't change.
Now if actually the Value was still 1 during that time, then my first guess is that you have a problem with Time Synchronization in your System.
If value transitions are faster than Min Time, two equal raw values may follow each other.
When avoiding Deadband Compaction (Basic History's Achilles Heel) it usually reflects pretty well what the OPC server is emitting.
I'd turn off Max Time while fault tracing (then, only true OPC server output is recorded).
Having a secondary client connected may also help to shed light on the problem.