Agilent Technologies E4438C - Generating a CW Signal Using VISA and C

Programming Examples
GPIB Programming Examples
Chapter 2 47
Generating a CW Signal Using VISA and C
This example uses VISA library functions to control the signal generator. The signal
generator is set for a CW frequency of 500 kHz and a power level of
−
2.3 dBm. Launch
Microsoft Visual C++ 6.0, add the required files, and enter the code into your .cpp source file.
The following program example is available on the ESG Documentation CD-ROM as
visaex4.cpp.
//****************************************************************************************
// PROGRAM FILE NAME: visaex4.cpp
//
// PROGRAM DESCRIPTION: This example demonstrates query commands. The signal generator
// frequency and power level.
// The RF state of the signal generator is turn on and then the state is queried. The
// response will indicate that the RF state is on. The RF state is then turned off and
// queried. The response should indicate that the RF state is off. The query results are
// printed to the to the display window.
//
//****************************************************************************************
#include "StdAfx.h"
#include <visa.h>
#include <iostream>
#include <stdlib.h>
#include <conio.h>
void main ()
{
ViSession defaultRM, vi; // Declares variables of type ViSession
// for instrument communication
ViStatus viStatus = 0; // Declares a variable of type ViStatus
// for GPIB verifications
char rdBuffer [256]; // Declare variable to hold string data
int num; // Declare variable to hold integer data
viStatus=viOpenDefaultRM(&defaultRM); // Initialize VISA system
// Open session to GPIB device at address 19
viStatus=viOpen(defaultRM, "GPIB::19::INSTR", VI_NULL, VI_NULL, &vi);
if(viStatus){ // If problems then prompt user
printf("Could not open ViSession!\n");
printf("Check instruments and connections\n");
printf("\n");
exit(0);}
viPrintf(vi, "*RST\n"); // Reset the signal generator
viPrintf(vi, "FREQ 500 kHz\n"); // Set the source CW frequency for 500 kHz
viPrintf(vi, "FREQ:CW?\n"); // Query the CW frequency
viScanf(vi, "%t", rdBuffer); // Read signal generator response
printf("Source CW frequency is : %s\n", rdBuffer); // Print the frequency