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Rank: Newbie
Groups: Member
Joined: 11/11/2008
Posts: 4
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I need help with writing code in VB.Net to display values of a point starting from when another value equals zero until that value equals zero again. In other words, I am trying to view "batch data" without setting up PIBatch. We have a cycle time counter so when the counter goes to zero, that is the end of the batch. I'd then like to view data such as max, min, etc for various points. If anyone can help, I'd be extremely thankful.
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OSIsoft vCampus is a subscription-based, online offering that consists of providing everything people need to develop applications on the PI System. We invite you to take a "tour" of the OSIsoft Virtual Campus - also feel free to consult the FAQ or contact OSIsoft vCampus for more details.
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 617
Location: Cheshire, United Kingdom.
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Hello jib2000, So you would like to know the timestamp when the PI tag was 0 (End Time) and then search back in time until a 0 is encountered once again (Start Time)? Those timestamps will then be used for other PI tags to get your data - essentially an Event Frame. Let me know if this is correct and I will post up an example for you. Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 617
Location: Cheshire, United Kingdom.
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Here are 2 example functions that you could use to extract the data:
Code: Private Function RetrievePIValues(ByVal PITag As String, ByVal StartTime As String, ByVal EndTime As String) As PISDK.PIValues
Dim Ret As PISDK.PIValues
If ConnectToPI() Then
Dim PIPnt As PISDK.PIPoint = PIServer.PIPoints(PITag)
Ret = PIPnt.Data.RecordedValues(StartTime, EndTime)
If Not Ret.Count > 0 Then Throw New Exception("No values retrieved for supplied time.")
Else
Throw New Exception("Cannot connect to PI!")
End If
Return Ret
End Function
Private Function RetrieveSummary(ByVal PITag As String, ByVal StartTime As String, ByVal EndTime As String, ByVal SummType As PISDK.ArchiveSummaryTypeConstants) As PISDK.PIValue
Dim Ret As PISDK.PIValue
If ConnectToPI() Then
Dim PIPnt As PISDK.PIPoint = PIServer.PIPoints(PITag)
Ret = PIPnt.Data.Summary(StartTime, EndTime, SummType)
If Not Ret.IsGood Then Throw New Exception("No good value returned for summary.")
Else
Throw New Exception("Cannot connect to PI!")
End If
Return Ret
End Function
And examples of how to implement them:
Code: Dim PIVals As PISDK.PIValues = Me.RetrievePIValues("sinusoid", "*-7d", "*-5d")
Dim PIVal As PISDK.PIValue = Me.RetrieveSummary("sinusoid", "*-7d", "*-5d", PISDK.ArchiveSummaryTypeConstants.astAverage) Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Administration
Groups: Administration
Joined: 6/20/2008
Posts: 617
Location: Cheshire, United Kingdom.
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To find when your PI tag had 0 as a value you would need to use a filter on a date range search to find all archive events when your filter match is true.
So you could do:
Code: Private Function RetrievePIValuesWithFilter(ByVal PITag As String, ByVal StartTime As String, ByVal EndTime As String, [b]ByVal Filter As String[/b]) As PISDK.PIValues
Dim Ret As PISDK.PIValues
If ConnectToPI() Then
Dim PIPnt As PISDK.PIPoint = PIServer.PIPoints(PITag)
Ret = PIPnt.Data.RecordedValues(StartTime, EndTime, PISDK.BoundaryTypeConstants.btAuto, Filter)
If Not Ret.Count > 0 Then Throw New Exception("No values retrieved for supplied time.")
Else
Throw New Exception("Cannot connect to PI!")
End If
Return Ret
End Function
And to implement:
Code:Dim PIVals As PISDK.PIValues = Me.RetrievePIValuesWithFilter("sinusoid", "*-7d", "*-5d", "'sinusoid'=0")
For Each PIVal As PISDK.PIValue In PIVals
Dim TheTime As String = PIVal.TimeStamp.LocalDate.ToString()
Next
Hope this helps!
Rhys.Principal Consultant
Real-Time Data Management @ Wipro Technologies
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Rank: Newbie
Groups: Member
Joined: 11/11/2008
Posts: 4
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Thanks. I'll try it out and let you know if it works.
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Rank: Newbie
Groups: Member
Joined: 6/28/2011
Posts: 3
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Can u give the code to extract data from "PI system" using VB
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Rank: Newbie
Groups: Member
Joined: 8/2/2011
Posts: 1
Location: India
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Sir, I am new to PI application. I am developing a system in VB.net where I want to check a condition/expression at current time say TagVal('TagName')<480 and if this condition is true then a messagebox should pop up Message("Condition evaluated to true"); I have tried the codes provided here but  Please Help!! Thanks in advance
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