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Using an Expression to Identify Spikes In Data

Question asked by CarissaG on Jan 25, 2019
Latest reply on Jan 28, 2019 by Eugene Lee

Question Using Expressions:

Hello PI World! I’m trying to use expressions on Excel in conjunction with my PI Historian to filter data and identify spikes in a tag value. Specifically, there is a KW Import tag that spikes heavily but only for a second and then returns to a value very close to what it was just before the spike. My goal is to identify the spike and pull a report that shows its value and the timestamp.

It’s tricky because (1) there are multiple spikes within a 24 hour period, (2) each “spike” does not exceed a particular value ( i.e I can’t apply a filter at say 10,000 KW) and (2) the percentage of the “spike” isnt always the same.

I’d like to try to put as little stress on the Historian as possible – I can do it manually by scouring the trend report but it’s so manually intensive that it’s not cost effective for the customer if I tackle it this way. Is there an effective method to do this?

Any information would be greatly appreciated!

Best,

Carissa G.

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