HP 53150A Series, Programming Manual

Page: 98 / 186

Chapter 3 Programming Your Counter for Remote Operation
Programming Examples
3-58 Programming Guide
3
Making a Frequency Measurement (C)
/* This program configures the counter to make 10 frequency measurements
on channel 1 followed by 10 on channel 2.
The results are displayed on the computer monitor.
The program comments discuss the meaning of each command.
ASCII result format is used to preserve resolution. */
#include <stdio.h
#include <string.h
#include “CHPIB.H”
#include “CFUNC.H”
void sendhp(char *);
/* function to send command to counter */
/* global data */
long ctr=703;
/* Counter is at address 03. HP-IB is at select code 7 */
int error;
void main()
{
long isc=7;
/* Select code 7 */
int state=1; /* Used in IOEOI */
int i; /* Used for loop counter */
int samples=10; /* Number of measurements to take */
int length=23; /* Max number of bytes per measurements */
char freq[23]; /* Array to hold frequency string */
IORESET(isc); /* Clear the HP-IB interface */
sendhp(“*RST”); /* Reset the counter */
sendhp(“*CLS”); /* Clear event registers and error queue */
sendhp(“*SRE 0”); /* Clear service request enable register */
sendhp(“*ESE 0”); /* Clear event status enable register */
sendhp(“:STAT:PRES”); /* Preset enable registers and transition
filters for operation and questionable
status structures
*/
IOEOI(isc,state); /* Enable use of EOI */
sendhp(“:FUNC ‘FREQ 1’”);/* Measure frequency on channel 1
Note that the function must
be a quoted string. The actual
string sent to the counter is ‘FREQ 1’. */
for (i=1; i<=samples ;i++)
{
sendhp(“INIT”); /* Start a measurement */
sendhp(“DATA?”);
IOENTERS(ctr,freq,&length);
/* fetch the data */
length=strlen(freq); /* Get length of result so */
freq[length-1]=’\0’; /* the linefeed can be removed*/
printf (“Frequency %d = %s Hz\n”,i,freq);
}
printf(“Press a key to continue\n”);
getch();
sendhp(“:FUNC ‘FREQ 2’”);
/* Change channels */
for (i=1; i<=samples ;i++)
{
sendhp(“INIT;*WAI;:DATA?”); /* Start a measurement */
IOENTERS(ctr,freq,&length); /* fetch the data */
length=strlen(freq); /* Get length of result so */
freq[length-1]=’\0’; /* the linefeed can be removed*/
printf (“Frequency %d = %s Hz\n”,i,freq);
}
printf(“Press a key to continue\n”);