I am using the tagmax and tagmin PE functions in a PI AF analytics to calculate the difference between the max and min values for a PI tag over a set time period. I am outputting the difference as a PI tag. If I backfill and preview the PI tag data it shows the expected differences. If I look at the trend for the data it appears interpolated and averaged between the data points. When I pull the data into excel with PI Datalink the data is interpolated. Here is an example:
|Date||PI datalink||preview data|
|7/26/2018||30 257||25 607|
I was wondering what the issue is. Do I need to change something fundamental about the PI tag so that it only displays discreet data and doesn't try to interpolate it?