Programming Guide

SIGLENT
SVA1000X Programming Guide 73
Existing Item. Search for the visa32.bas file in the include folder under the NI-VISA
installation path and add the file.
This allows the VISA functions and VISA data types to be used in a program.
3、 Add codes:
1) USBTMC access code:
Write a function Usbtmc_test:
Private Function Usbtmc_test() As Long
' This code demonstrates sending synchronous read & write commands
' to an USB Test & Measurement Class (USBTMC) instrument using
' NI-VISA
' The example writes the "*IDN?\n" string to all the USBTMC
' devices connected to the system and attempts to read back
' results using the write and read functions.
' The general flow of the code is
' Open Resource Manager
' Open VISA Session to an Instrument
' Write the Identification Query Using viWrite
' Try to Read a Response With viRead
' Close the VISA Session
Const MAX_CNT = 200
Dim defaultRM As Long
Dim instrsesn As Long
Dim numlnstrs As Long
Dim findList As Long
Dim retCount As Long
Dim status As Long
Dim instrResourceString As String * VI_FIND_BUFLEN
Dim Buffer As String * MAX_CNT
Dim i As Integer
' First we must call viOpenDefaultRM to get the manager
' handle. We will store this handle in defaultRM.
status = viOpenDefaultRM(defaultRM)
If (status < VI_SUCCESS) Then
resultTxt.Text = "Could not open a session to the VISA Resource Manager!"
Usbtmc_test = status
Exit Function
End If
' Find all the USB TMC VISA resources in our system and store the
' number of resources in the system in numInstrs.