EventPipe Example


This example, during the Form_Load, populates the edit boxes with tags whose events will be collected.  A PI-SDK control (server pick list) allows selection of the desired server.  When the "Begin collecting" button is hit, the application connects to the selected server, grabs an EventPipe for each tag and sets the pipe's MaxCount property to the value in the corresponding text box.  A timer is enabled at this point to periodically check the pipes for values.  On each timer event the app gets the count from each event pipe and graphically displays how full the pipe is.  When the "Take All" button is clicked under any tag, EventPipe.TakeAll is called and the value of the most recent event (highest index) is dispayed below the button. with the timestamp shown just below.  

Build the EventPipe example as follows:

1. Create a new project and add a reference to the PISDK library.

2. Add a reference to the PI-SDK Control under the Project | Components menu.

3. Add the visual elements as shown in the picture. Name the objects as follows

Object Name
Begin Collecting button btnBegin
Stop Collecting button btnStop
Tagname edit boxes txtTagName1 control array
Max edit boxes txtMax1 control array
Rectangles for % full display ShapeFill1control array
Take All buttons btnTakeAll1 control array
Value display labels lblValue1 control array
Timestamp display labels lblTime1 control array
Timer Timer1

4. Cut and paste the code below into the project.

Dim srv As Server
Dim evp1(3) As EventPipe
Private Sub btnBegin_Click()
   Set srv = PISrvPickList1.SelectedServer
   If Not srv.Connected Then
      Dim cnxn As New Connections
   End If
End Sub

Private Sub MonitorPipes()
On Error GoTo eh
   Dim i As Integer
   Dim pt As PIPoint
   For i = 0 To 2
      Set pt = srv.PIPoints(txtTagName1(i).Text)
      Set evp1(i) = pt.Data.EventPipe
      evp1(i).maxCount = CInt(txtMax1(i).Text)
   Next i
   Timer1.Enabled = True
   Timer1.Interval = 1000
Exit Sub
   MsgBox Err.Description
End Sub

Private Sub btnStop_Click()
   Dim i As Integer
   Timer1.Enabled = False
   For i = 0 To 2
      Set evp1(i) = Nothing
   Next i
End Sub

Private Sub btnTakeAll1_Click(Index As Integer)
Dim evobjs1() As Object
On Error GoTo eh
   If evp1(Index).Count = 0 Then
      Exit Sub
   End If
   Dim endIndex As Long
   endIndex = evp1(Index).Count
   ReDim evobjs1(1 To evp1(Index).Count)
   Dim vtEvents As Variant
   vtEvents = evp1(Index).TakeAll
   evobjs1 = vtEvents
   Dim pievobj As PIEventObject
   Set pievobj = evobjs1(endIndex - 1)
   Dim pv As PointValue
   Set pv = pievobj.EventData
   lblValue1(Index).Caption = CStr(pv.PIValue.Value)
   lblTime1(Index).Caption = CStr(pv.PIValue.TimeStamp.LocalDate)
Exit Sub
   MsgBox Err.Description
End Sub

Private Sub Timer1_Timer()
   ' update bar display
   Dim maxCount As Single
   Dim currentCount As Single
   Dim dblBarHeight As Single
   Dim dblPercentFull As Single
   Dim arrRGB(5) As Long
   arrRGB(0) = RGB(0, 255, 0)
   arrRGB(1) = RGB(128, 255, 0)
   arrRGB(2) = RGB(255, 255, 0)
   arrRGB(3) = RGB(255, 128, 0)
   arrRGB(4) = RGB(255, 0, 0)
   For i = 0 To 2
      maxCount = evp1(i).maxCount
      currentCount = evp1(i).Count
      dblPercentFull = currentCount / maxCount
      If dblPercentFull <= 0.2 Then
         colorIndex = 0
         If dblPercentFull <= 0.4 Then
            colorIndex = 1
            If dblPercentFull <= 0.6 Then
               colorIndex = 2
               If dblPercentFull <= 0.8 Then
                  colorIndex = 3
                  colorIndex = 4
               End If
            End If
         End If
      End If
      ShapeFill1(i).FillColor = arrRGB(colorIndex)
      dblBarHeight = dblPercentFull * Shape1(i).Height
      ShapeFill1(i).Left = Shape1(i).Left
      ShapeFill1(i).Width = Shape1(i).Width
      ShapeFill1(i).Height = dblBarHeight
      ShapeFill1(i).Top = Shape1(i).Top + (Shape1(i).Height - ShapeFill1(i).Height)
      lblCurrent1(i).Caption = CStr(evp1(i).Count)
   Next i
End Sub
Private Sub Form_Load()
   txtTagName1(0) = "sinusoid"
   txtTagName1(1) = "cdm158"
   txtTagName1(2) = "cdt158"
   txtMax1(0) = "10"
   txtMax1(1) = "20"
   txtMax1(2) = "15"
End Sub
Private Sub ClearDisplay()
   For i = 0 To 2
      ShapeFill1(i).FillStyle = vbFSSolid
      ShapeFill1(i).FillColor = RGB(128, 128, 128)
      ShapeFill1(i).Left = 0
      ShapeFill1(i).Top = 0
      ShapeFill1(i).Height = 0
      ShapeFill1(i).Width = 0
      lblValue1(i).Caption = ""
      lblTime1(i).Caption = ""
   Next i

End Sub

Enabling Operational Intelligence