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The following example builds upon the Tutorial Using in VB6. Private Sub Form_Load()
Simple Read Example
'define the webclient object
Dim opcwebclient As New EasyDA3
'define our object to receive the read
Dim valueTimeQuality As VTQ3
'read the tag
Set valueTimeQuality = opcwebclient.ReadItem("", "OPCLabs.KitServer.2", "Simulation.Random")
'now to check the status of the instruction
If Err.Number = 0 Then
'now to check the quality of the tag
If valueTimeQuality.Quality >= 192 Then
MsgBox valueTimeQuality.Value +
& " (" & valueTimeQuality.Quality & ") " _
& " @ " & valueTimeQuality.TimeStamp
Else
MsgBox "Quality not good: " _
& "quality: " & valuetimeQuality.Quality
End If
Else
MsgBox "An error occurred: " & Err.Number
End If
End Sub
Reading Multiple Tags within a single transaction:
Private Sub Form_Load()
'define our opcwebclient object
Dim EasyDA As New
EasyDA3
'define our array of tags within the call to read them
Dim Values
Values = EasyDA.ReadMultipleItems("", "
OPCLabs.KitServer.2", _
Array("Simulation.Random", "Trends.Ramp (1 min)", "Trends.Sine (1 min)", "Simulation.Register_I4"))
'now to check what was read by iterating thru the received collection
Dim I
For I = LBound(Values) To UBound(Values)
'check if the data-type of the object in the collection is of type "error"
If VarType(Values(I)) <> 10 Then
'everything is ok
Text1.Text = Text1.Text & "Element " & I & ": " & Values(I) & vbCrLf
Else
'an error has occured, so lets handle it
On Error Resume Next
EasyDA.RaiseError Values(I)
'display a message indicating the error
Text1.Text = Text1.Text & vbCrLf & "** " & Err.Source & ": " & Err.Description & " (0x" & Hex(Err.Number
) & ")" & " **"
On Error Goto 0
End If
Next
End Sub
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