Little help with IPICalculation

Discussion created by cguimaraes Employee on Dec 22, 2010
Latest reply on Jan 3, 2011 by cguimaraes

Hi Everyone,


This is my first post, so first of all, thanks for the help.


What I`m trying to perform I believe that is simple, the idea is to work with 3 float 32 tags. ("_Raw"," _Comp" and " _Error")


The Tag  "_Comp" is the tag "_Raw" with a greater compression parameter.


I Want to perform the calc "_Raw" - "_Comp" (interpolated) and store the diference at tag _Error.


I have tried:


Dim _point1 As PISDK.PIPoint = _server.PIPoints("_Raw")
Dim _point2 As PISDK.PIPoint = _server.PIPoints("_Comp")
Dim _point3 As PISDK.PIPoint = _server.PIPoints("_Error")
Dim x As IPICalculation
Dim Calc As PIValues
x = myPIServer
Calc = x.Calculate("y","t", "'_Raw' - '_Comp'", SampleTypeConstants.stRecordedValues, "")
_point3.Data.UpdateValues(Calc, DataMergeConstants.dmReplaceDuplicates)


The problem is that when I double check the calculated data at excel, I don't have the same results.


Any Ideas what I'm doing wrong?