Programming instructions

Programming Examples
GPIB Programming Examples
Chapter 2 43
Queries Using NI-488.2 and C++
This example uses the NI-488.2 library to query different instrument states and conditions.
Launch Microsoft Visual C++ 6.0, add the required files, and enter the following code into
your .cpp source file.
The following program example is available on the PSG Family Documentation CD-ROM as
niex3.cpp.
//*************************************************************************************
// PROGRAM NAME: niex3.cpp
//
// PROGRAM DESCRIPTION: This example demonstrates the use of query commands.
//
// The signal generator can be queried for conditions and instrument states.
// These commands are of the type "*IDN?" where the question mark indicates
// a query.
//
//*************************************************************************************
#include "stdafx.h"
#include <iostream>
#include "windows.h"
#include "Decl-32.h"
using namespace std;
int GPIB0= 0; // Board handle
Addr4882_t Address[31]; // Declare a variable of type Addr4882_t
int main()
{
int sig; // Declares variable to hold interface descriptor
int num;
char rdVal[100]; // Declares variable to read instrument responses
sig = ibdev(0, 19, 0, 13, 1, 0); // Open and initialize a device descriptor
ibloc(sig); // Places the signal generator in local mode
ibclr(sig); // Sends Selected Device Clear(SDC) message
ibwrt(sig, "*RST", 4); // Places signal generator in a defined state
ibwrt(sig, ":FREQuency:CW?",14); // Querys the CW frequency
ibrd(sig, rdVal,100); // Reads in the response into rdVal
rdVal[ibcntl] = ’\0’; // Null character indicating end of array
cout<<"Source CW frequency is "<<rdVal; // Print frequency of signal generator
cout<<"Press any key to continue"<<endl;
cin.ignore(10000,’\n’);
ibwrt(sig, "POW:AMPL?",10); // Querys the signal generator
ibrd(sig, rdVal,100); // Reads the signal generator power level
rdVal[ibcntl] = ’\0’; // Null character indicating end of array
// Prints signal generator power level
cout<<"Source power (dBm) is : "<<rdVal;
cout<<"Press any key to continue"<<endl;