I am trying to monitor my PLC for setpoint changes which don't occur very often.
I am using the "Only evaluate when values have changed" without a "Trigger on Item".
I have about 30 setpoints so this feature works well without having to write PLC code.
The trigger always works when the values change.
Issue:
My issue is sometimes it inserts a record even though the values haven't changed. This seems like maybe it is somekind of OPC disconnect but I'm not really sure. I get a few random inserts happening at night when the machine is idle but no one is at the machine. I end up with essentially duplicate records (even though no changes occur) every morning when I check.
Solution:
Not sure what to do to eliminate this (or if its possible). I was thinking about writing code in SQL db to delete these duplicate values via Rollback. Any body else come across this and have any good solutions?
Thanks