3 Replies Latest reply on Dec 13, 2011 2:26 PM by andreas

    Sum of Tag values in Processbook

    sigurdsen

      I have a question which I thought was elementary.

       

      A tag has values every now and then (say every day, but incidentally two values on the same day and some days without values). 

       

      I need to know the sum of these values from a given time untill now in Processbook, without ODBC or PI Totalizer, ACE, VBA or Datalink. Can I do this with PI Calculation?

       

      I tried TagMean*EventCount, but I have a hard time getting the correct answer.

       

      Anyone tried this?

       

      Best regards,

       

      Torbjørn Sigurdsen

        • Re: Sum of Tag values in Processbook
          hanyong

          I would have thought that TagMean * EventCount using PI Calculation would have given you what you want. Can you share a bit more of your PI Calculation configuration and how you are attempting to verify the result? 

            • Re: Sum of Tag values in Processbook
              sigurdsen

              Well, that was what I thought as well. I created a new tag and set it up with 2 values: 10 and 100. I got 220 as a result. And it didn't improve with more values.

               

              I think it is connected to counting snapshot and substituted values as events. And substituted events is potentially a problem for me.

               

              The PI Calculation was something like this TagMean('<tagname>','01-jan','*') * EventCount('<tagname>','01-jan','*').

                • Re: Sum of Tag values in Processbook
                  andreas

                  I see - there is an issue with EventCount. Eventcount does return 1 or 2 values more as expected in certain circumstances. You may contact techsupport to open a call for this. The issue you are experiencing is listed as 17126OSI8. By taking this to techsupport you will get notified if this issue gets fixed.