A-2 Visual Basic Appendix A — Examples
A-4 PN: 10580-00322 Rev. F S331L PM
A-2 Visual Basic
This function can be called in a Visual Basic program. It sends the *IDN? query to the
instrument and returns the byte count and ASCII response string.
Rem This example is based on Example 2-1 from the NI-VISA User Manual.
Public Sub IdnMain(ByVal address As String, ByRef byteCount As String,
ByRef returnBytes As String)
Const BUFFER_SIZE = 200
Dim stat As ViStatus
Dim dfltRM As ViSession
Dim sesn As ViSession
Dim retCount As Long
Dim buffer As String * BUFFER_SIZE
Rem ***Include visa32.dll as a reference in your project.***
Rem Begin by initializing the system
stat = viOpenDefaultRM(dfltRM)
If (stat < VI_SUCCESS) Then
Rem Error initializing VISA...exiting
MsgBox “Can't initialize VISA”
Exit Sub
End If
Rem Open communication with Device
Rem NOTE: For simplicity, we will not show error checking
Rem TODO: Add error handling.
stat = viOpen(dfltRM, address, VI_NULL, VI_NULL, sesn)
Rem Set the timeout for message-based communication
Rem TODO: Add error handling.
stat = viSetAttribute(sesn, VI_ATTR_TMO_VALUE, 120000)
Rem Ask the device for identification
Rem TODO: Add error handling.