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How to count intervals within sample period where tag value over threshold

Question asked by troyh on Sep 3, 2015
Latest reply on Sep 3, 2015 by Dan Fishman

Hi,

 

I am using PI DataLink to calculate the % time (within a specified window) a tag is greater than a threshold value.

I have found approaches to this using both the PITimeFilterVal function, and the PIAdvCalcExpFilVal function.

 

I would now like to perform a similar comparison (tag value to threshold), on an interval basis, but return a count of the intervals where the tag value exceeds the threshold for more than half of the interval (i.e. I would like to return a single value only.

 

I have managed to calculate the % time exceeded for each interval (using the PIAdvCalcExpFilDat function), but this returns an array (i.e. one value for each interval).

 

Logically I want something like:

 

returned value = count of intervals in timespan, where tagvalue > threshold value, for > 50% of interval

   

 

Is this kind of query possible?

 

Thanks in advance.

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