I am trying to get a better understanding of your use case:
- Since you mentioned "Time Filtered formula", I assume you are using the PI DataLink add-in to Microsoft Excel. Is that correct?
- Do you want to just calculate the average of some tags (while filtering zeros and negative values) or are you doing further calculation on top of this average?
- Where do you need to exhibit the results of this calculation?
In any case, f you want to just filter zeros and negative values in a Performance Equation (be it in PI DataLink, a Performance Equation calculated tag, PI Totalizer Subsystem tag, etc), this expression might be helpful:
Avg(if('sinusoid'>0) then 'sinusoid' else NoOutput(), if('cdt158'>0) then 'cdt158' else NoOutput())
This returns the average of tags SINUSOID and CDT158, but filters zeros and negative values.