Agilent Technologies Model A.08.xx manual 122

Programming Examples

Reading Trace Data Using 32-bit Real Format (GPIB)

/*Program Variables*/ ViStatus viStatus= 0;

ViChar _VI_FAR cResult[5000] = {0};

ViReal32 dTraceArray[401] = {0};

char cBufferInfo[6]= {0}; long lNumberBytes =0L; long lOpc =0L;

unsigned long lRetCount = 0L; int iSize = 0;

/*BytesPerPoint is 4 for Real32 or Int32 formats, 8 for Real64, and 2 for Uint16*/ int iBytesPerPnt = 4;

int iSwpPnts = 401; int iDataBytes=1604; int iHeaderBytes=6; FILE *fTraceFile;

/* Open a GPIB session at address 18*/ viStatus=viOpenDefaultRM(&defaultRM); viStatus=viOpen(defaultRM,"GPIB0::18",VI_NULL,VI_NULL,&viESA); if(viStatus)

{

printf("Could not open a session to GPIB device at address 18!\n"); exit(0);

}

/*Clear the instrument */ viClear(viESA);

/*Reset the instrument. This will set number of sweep points to default of 401*/ viPrintf(viESA,"*RST\n");

/*Display the program heading */

printf("\n\t\t Read in Trace Data using 32-bit Real Format (using GPIB) \n\n" );

/* Set the input port to the 50MHz amplitude reference*/ Route50MHzSignal();

/*Query number of sweep points per trace (firmware revision A.04.00 and later)*/ /*For firmware revisions prior to A.04.00, the number of sweep points is 401*/ iSwpPnts=401; viQueryf(viESA,"SENSE:SWEEP:POINTS?\n","%d",&iSwpPnts);

/*Calculate number of bytes in the header. The header consists of the "#" sign*/ /*followed by a digit representing the number of digits to follow. The digits */ /*which follow represent the number of sweep points multiplied by the number */

/*of bytes per	point. */
iHeaderBytes =	3;	/*iDataBytes >3, plus increment for "#" and "n"*/

122 Chapter 3