Agilent Technologies 11867A? Instrukcja Obsługi Pobierz pdf (Strona 142)

144 Chapter 9

Programming Examples

Programming in C Using the VISA

Programming Examples

Example Program

This example program queries a LAN device for an identification string

and prints the results. Note that you must change the address.

/*idn.c - program filename */

#include "visa.h"

#include <stdio.h>

void main ()

{

/*Open session to LAN device at IP address 192.168.0.2

ViOpenDefaultRM (&defaultRM);

ViOpen (defaultRM, "TCPIP0::192.168.0.2::inst0::INSTR",

VI_NULL,

VI_NULL, &vi);

/*Initialize device */

viPrintf (vi, "*RST\n");

/*Send an *IDN? string to the device */

printf (vi, "*IDN?\n");

/*Read results */

viScanf (vi, "%t", &buf);

/*Print results */

printf ("Instrument identification string: %s\n", buf);

/* Close sessions */

viClose (vi);

viClose (defaultRM);

}

Including the VISA Declarations File

For C and C++ programs, you must include the visa.h header file at

the beginning of every file that contains VISA function calls:

#include “visa.h”

This header file contains the VISA function prototypes and the

definitions for all VISA constants and error codes. The visa.h header

file includes the visatype.h header file.

The visatype.h header file defines most of the VISA types. The VISA

types are used throughout VISA to specify data types used in the

functions. For example, the viOpenDefaultRM function requires a

pointer to a parameter of type ViSession. If you find ViSession in the

visatype.h header file, you will find that ViSession is eventually

typed as an unsigned long.

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Agilent Technologies 11867A? Instrukcja Obsługi Strona 142