AnsweredAssumed Answered

Totalizer vs. PI AF

Question asked by PernilleSilberg on Sep 18, 2018
Latest reply on Sep 21, 2018 by Dan Fishman

Hi There,

We want to replace our current totalizer tags with PI AF - if this is possible..

I have the challenge that i want to calculate an average of a tag/or attribute over a given period, lets say 30 min, but i want the timestamp to be set to the start of the period.

Using totalizer this is a no brainer - but i would rather avoid totalizers as we somtimes have delay in data and therefore we sometimes get wrong calculated totalizers.

 

What i so far have tried is to use PI AF (we are using version 2017 R2) - but we get no data into our database.

my expression is Tagavg('attribute','*-30m','*'), periodic triggered every 30 min and with the "output time stamp" set to relative to triggertime: *-30m. Here i'm thinking that i want the timestamp for the avg to be in the start of the period and not in the end... Am i thinking wrong ?

The system gives me in the preview results a nice table and trend - that shows me the data i want - and I can create the tags - but no data is written to the tag. The tag just is freezed at pt created.

Please assist

Cheers Pernille

Outcomes