Hey Vasant:

I learned how to do that browsing these forums (i believe you can do something like below, with the proper pi-sdk library references).

There is a method/function called summary inside PIData that takes as arguments StartTime, EndTime, and SummaryType.

for e.g.

dim PiServerVar as pisdk.server
set PiServerVar = PISDK.Servers("Your_Server_Name")

dim myPiPoint as pisdk.pipoint
set myPiPoint = PiServerVar.PIPoints("Your_Tag_Name")

dim pval as pisdk.pivalue
set pval = myPiPoint.Data.Summary(StartTime, EndTime, astAverage)

' pval.value is a number representing the average value of your tag over the StartTime to EndTime interval


Wait for Rhys to truly help you :] but I think the Summary method will work for tag averages in pi-sdk

Edit:

http://www.rjksolutionsl..._Find-MinMax-Value.aspx

(scroll down to post #5 , by Rhys , and there's a nice function he wrote entitled GetSummary which should do the trick)