I have an indicator that is collected from an online data source. The indicator is collected on a polling schedule every 6 hours.
It is measured as an accumulated value and has a roll-over value of 1,000,000.
When the online source (PLC) is turned off for maintenance, a 0 can be recorded for the current value causing the accumulated value to rollover.
Once the PLC is turned back on, the counts are read but with the addition of 1,000,000 counts.
Any suggestions on how to correct this issue?
FYI.. this is APM V7.8.
Thanks for any ideas.
Thanks for response Giselle. Unfortunately I need something that is more automated. We use this counter as a trigger for maintenance and this can cause PM work requests/orders to be activated unnecessarily. Because it updates every 6 hours, this can be any time of night, weekends, etc...
If the PLC being offline is the only time you would expect a "0", then you could set a minimum reading on the indicator.
on my screen the limits you describe are greyed out. I assume that is because it is an accumulated value. I think by forcing the value to a minimum will have the same affect as entering a 0. It would still roll-over.
The minimum input would serve as a mask to prevent the reading from processing. I do see you are correct, it isn't available on a meter reading. My next experiment would be to use ODC to collect the meter reading, and then set up a calculated meter indicator and use a filter in the calculation to eliminate the zero's. Another thing we have done (although not on a meter) is have a second ODC indicator to check the status of the component, and use that in the rule or calculation to determine what to do with the data. We solved false alarms on ODC temperature and pressure indicators this way.