BNC 645 - Manual (Page 187)

187
triggers
.Output = "Init" ' Place dmm in 'wait-for-trigger' state
.Output = "*OPC" ' Set 'operation complete' bit in standard
' event registers when measurement is complete
End With
'""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
' enable the timer to poll gpib once per second
tmrPollForSRQ.Enabled = True
' give message that meter is initialized
' give message that configuration is done
txtData.Text = "Meter configured and " & vbCrLf & _
"Initialized"
Exit Sub
StartReadingsError:
Debug.Print "Start Readings Error = "; Err.Description
End Sub
Private Sub tmrPollForSRQ_Timer() 'Timer1
' This timer when enabled will poll the GPIB
' and return the status byte to indicate if SRQ is set
On Error GoTo pollerror
Continued on next page
' this will also change the timeout
statusValue = Model 645.WaitOnSRQ(100) ' WaitOnSRQ(100ms)
' Set the timeout back to 10 sec,
Model 645.TimeOut = 10000
If statusValue = 64 Then ' SRQ from Operation complete
' Turn off the timer and stop polling.
tmrPollForSRQ.Enabled = False
Debug.Print "SRQ is set, getting data"
' Get the Data, the meter is ready
ReadData
End If
Exit Sub
pollerror:
Debug.Print "No SRQ yet, Poll error = "; Err.Description
End Sub
Private Sub ReadData()
' Once the SRQ is detected, this routine will
' get the data from the meter
' Called by: PollForSRQTimer_Timer
'
Dim readings() As Double
Dim i As Long
On Error GoTo ReadDataError
' dimension the array for the number of readings
With Model 645
.Output = "Fetch?" ' Query for the data in memory
readings = .Input ' get the data and parse into the array
End With