152 Chapter 3
Programming Examples
Status Register–Determine When a Measurement is Done
/* Make sure it is an SRQ event, ignore if stray event*/
if (eventType!=VI_EVENT_SERVICE_REQ)
{
printf ("\n Stray event type0x%1x\n",eventType);
/*Return successfully*/
return VI_SUCCESS;
}
/* When an interrupt occurs,determine which device generated the interrupt
(if an instrument other than the ESA generates the interrupt, simply report
"Instrument at GPIB Address xxx Has Generated an Interrupt").*/
printf ("\n\n SRQ event occurred!\n");
printf ("\n ... Original Device Session = %t\n",viESA);
/*Get the GPIB address of the insrument, which has interrupted*/
viQueryf(viESA,"SYST:COMM:GPIB:SELF:ADDR?\n","%t", cBuf);
printf ("\n Instrument at GPIB address %s has generated an interrupt!\n",cBuf);
/*Get the status byte*/
/* If the ESA generated the interrupt, determine the nature of the interrupt;
did the measurement complete or an error message occur?*/
viQueryf(viESA, "*ESR?\n", "%d", &iStatusByte);
if ( (0x01 & iStatusByte))
printf("\n SRQ message:\t Measurement complete\n");
else if ( (0x02 | 0x10 | 0x20 & iStatusByte ))
printf ("\n SRQ message:\t Error Message Occurred\n");
/*Return successfully*/
iSrqOccurred =1;
viReadSTB(viESA,&iStatusByte);
return VI_SUCCESS;
}
/* Main Program*/
void main()
{
/*Program Variables*/
ViStatus viStatus = 0;
long lOpc=0;
/* Open a GPIB session at address 18*/
viStatus=viOpenDefaultRM(&defaultRM);
int address =18;
viStatus=viOpen(defaultRM,"GPIB0::18",VI_NULL,VI_NULL,&viESA);
if(viStatus)
{
