I am seeking the opinion of my fellow PI Administrators and OSI Professionals regarding choosing which PI Calculation technique to use under which circumstances. With 13 years of PI Administrative experience I do have some opinions of my own. But thought I would get yours. I understand that this is a broad topic and not intended to address how to solve any problem. Of the three calculating tools offered, PI-Performance Equations, PI-Totalizer, and PI-ACE what guidelines would you use for determining when to use each?

Additionally, with PI-ACE is it preferrable to use one large Module with many calculations or a separate module for each calculation? (Assuming many contexts per calculation in either case.)

If there is already a good blog or discussion topic on this, please let me know.

Hi David,

Do you only need to perform a calculation, or do you also need to persist the calculations? And are these persisted calculations then timeseries data?

In most cases, i prefer to use AF and not to persist the calculations. But that´s not always an option due to performance. It is impressive though how fast AF can produce data for a trend plot using large sets of calculations, table lookups, etc., so don´t dismiss this too quickly.