PLC 5000 trend problems

hmaree · Dec 8, 2017

We currently have Allenbradley PLC500 running in our factory. For some reason one PLC processor doesn't allow me to run trends. It keeps on saying "Warning: Data sample(s) discarded - Duplicate timestamps." Can anybody please help me with this problem.

Dravik · Dec 8, 2017

Well, if you are talking one of the Control or CompactLogic processors, I believe that error relates to the wallclock time changing backwards during trending.
Might see if you have any SSV or PTP things mucking w/ the time.

hmaree · Dec 8, 2017

Hi Dravik. Found these GSV/SSV logic and need to know if it's the requirement of the program to have them running or could it be disabled?

hmaree · Dec 8, 2017

SSv/GSV Logic

See attached SSV/GSV logic

Dravik · Dec 8, 2017

Well, i can't quite read that image. But I would check to see why it appears you are writing to the wall clock every scan?
I can't think of a good reason to be doing that, but I didn't write that program!

hmaree · Dec 8, 2017

Hi Dravik. You are correct, it is writing it to the WALLCLOCKTIME. Also not sure what the reason is behind it.

Operaghost · Dec 8, 2017

Usually the SSV writes the WALLCLOCK once a minute, once an hour, or once a day. It is not necessary to continuously write to it. Until there is something that conditions when the SSV writes to the WALLCLOCK, the Trend won't be able to run.

OG

PLC 5000 trend problems

hmaree

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