PNA - Getting Sweep data

Hi,

I'm an electronics student working for a electronic filters company over the summer programming.

I'm currently trying to writing a program in C for the PNA-L N5230C; that will set the start & stop frequency, set the number of sweep points, perform a single sweep and then get the result of sweep.

Everything is going well until I want to get the data from the Analyzer, as the text file made that should have the sweep data in doesn't have any.

I've looked Google to try and find a solution but not had much luck. I'm connecting to the analyzer via a USB B.

Any help would be much appreciated. Thanks.

#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <visa.h>

#define PROG    "AgilentTest.c\0"
#define V       "0.02\0"

char pna[26][6] = {
          "pna1", "pna2", "pna3", "pna4", "pna5",
          "pna6", "pna7", "pna8", "pna9", "pna10",
          "pna11", "pna12", "pna13", "pna14", "pna15",
          "pna16", "pna17", "pna18", "pna19", "pna20",
          "pna21", "pna22", "pna23", "pna24", "pna25"
          };

int main( void )
{
    int h1 = 0;
    ViSession defaultRM, vi;
    ViStatus viStatus = 0;
    char buff[256] = {0};
    ViChar _VI_FAR cResult[2000] = {0};
    FILE *fTraceFile;
    static ViChar *cToken;
    int iNum = 0, lCount = 0;
    int iSwpPnts = 401;
    int addr = 0;
    double startF = 1e9, stopF = 5.2e9;
    int count1 = 0;

    /*Welcome statements*/
    printf("\n\nAgilent PNA test program %s %s \n\n", PROG, V);
    printf("----------------------------------------------------\n");
    printf("Do not use for actual measurements\nThis program is for testing\n\n");
    printf("Press any key to connect to an analyzer\n");
    h1 = getch();

    /*Special Skip Statement*/
    if(h1 == 104)
    {
      printf("Please enter an address:\n");
      scanf ("%d",&addr);
      viStatus = viOpenDefaultRM(&defaultRM);
      viStatus = viOpen(defaultRM, pna[addr] ,VI_NULL,VI_NULL, &vi);

      if(viStatus)
      {
        system("CLS");
        printf("Could not make a conection at this addr\n");
        getch();
        exit(1);
      }
        printf("\n\n\n\tSkipping search Connection as addr %d => %s \n\n\n\n",addr, pna[addr]);
        goto exit1;
    }

    /*Loop through ID strings to conect the analyzer*/
    for(addr = 0; addr < 25; addr++)
    {
      printf("addr = %d\n", addr );
      printf("Pna = %s\n", pna[addr] );

      /*Attempt to connect to analyzer*/
      viStatus = viOpenDefaultRM(&defaultRM);
      viStatus = viOpen(defaultRM, pna[addr] ,VI_NULL,VI_NULL, &vi);

      /*check opening session sucess*/
      if(viStatus)
      {
        /*If there are still more ID strings to check reset viStatus*/
        if( addr < 24)
          viStatus = 0;

        /*If all ID strings have been checked*/
        else
        {
  		    system("CLS");
          printf("Could not open a session to the device at any location, last check was at:\n\n\t%s\n\n", pna[addr]);
          printf("Press any key to exit program\n");
          getch();
          viClose(vi);
          viClose(defaultRM);

          /*exit 1 => failure*/
          exit(1);
        }
      }
      else
        goto exit1;
    }

exit1:
      system("CLS");
      /*Turn off automatic sweeps*/
      printf("continuous sweeps are off\n");
      viPrintf(vi, "INIT:CONT OFF \n");

      /*Set up the analyser with values*/
      printf("Setting strat frequancy\n");
      viPrintf(vi, "SENS:FREQ:START %f\n", startF);

      printf("Setting stop frequancy\n");
      viPrintf(vi, "SENS:FREQ:STOP %f\n", stopF);

      printf("Setting the number of points in a sweep\n");
      viPrintf(vi,"SENSe1:SWEep:POIN %d\n", iSwpPnts);

      /*Display Off*/
      /*Should help increase time it takes to complete sweep*/
      viPrintf(vi, "DISP:ENAB OFF\n");

      /*Set analyzer trace data format to ASCII Format*/
      viPrintf(vi,"FORM:DATA ASC \n");

      /*Preform one sweep*/
      printf("Running a single sweep\n");
      viPrintf(vi, "SENS:SWE:MODE SINGle\n*OPC?\n");

      /*Get the data frome trace1*/
      viQueryf(vi,"%s\n", "%#t","TRAC:DATA? TRACE1" , &iNum , cResult);
      cToken  = strtok(cResult,",");

      fTraceFile=fopen("SweepReadings.txt","w");

      while (cToken != NULL)
      {
        lCount++;
        cToken =strtok(NULL,",");
        if (lCount != iSwpPnts)
          fprintf(fTraceFile,"\tAmplitude of point[%d] = %s dBm\n",lCount+1, cToken);
      }

      fprintf(fTraceFile,"\nThe Total trace data points of the spectrum are :[%d] \n\n",lCount);
      fclose(fTraceFile);

      printf("Get data finished, press any key to disconnect from the analyzer\n");
      getch();
      /*Turn the display on, reset the analyzer and close the session*/
      viPrintf(vi, "DISP:ENAB ON\n");
      viPrintf(vi, "INIT:CONT ON\n");
      viPrintf(vi, "*RST\n");
      viPrintf(vi, "HCOPY:FILE PNATempImage.png \n");
      printf("Closing the session\n");
      viClose(vi);
      viClose(defaultRM);

      return 0;
}