We are creating totalizer points to calculate Avg, Min, Max and Total at every 15min, 30min and 1hour, archive is enabled for all of these points. We have following doubts about these totalizer points

1. For 30min we would like to have 15min data as the input and make sure it runs after the 15min data is collected. This means the 30min should have two 15min data as the input. Can we configure this in PI server?

2. The 15min calculated data should consider only the previous 15min values stored for the specified tag source and not the entire data.

3. Suppose if we override any old value in the PI Archive, can we force these Totalizer points to recalculate the Avg, Min, Max and Total upto the last calculated time?

Thanks & Regards,

Kavita

Hi Kavita

Just like to clarify what you mean by "have 15min data as the input", are you referring to a Totalizer tag that closes every 15mins?

When we configure Totalizer tag, we usually refer the input as another PI tags that we are performing calculation on. Totalizer does accumulation calculation, meaning that once it is configure, it would use the new snapshot values of the input tags to perform calculation. From what you described, you just need to use the PI tag that gets the 15min data as the input (or source tag if you are using the PI SMT3 plugin to configure).

As to answer your 2nd question, if you configure totalizer to close a calculation every 30 minutes, it would use the new snapshot that is collected for the Input tag for calculation within 30 minutes period for calculation. When 30 minutes is up, it would close the calculation (writing a final result at the end of the 30 minute period) and reset the calculation for the next 30 minutes period. So the final result would be based data collected in the last 15 minutes only.

Because PI Totalizer does accumulation calculation based on snapshot values, there is no recalculation mechanism to perform calculation when the archive data is backfilled or overrided. Recalculation would be available if you are using Performance Equation (PE) and PI ACE.

If you just want to get a summary calculation results at fixed interval, PE can do the same for you. There is a difference using PE and Totalizer to perform such calculations though: