/*
* This example assumes the user's PC has a National Instruments GPIB board. The example is comprised of three basic parts:
*
* 1. Initialization
* 2. Main Body
* 3. Cleanup
*
* The Initialization portion consists of getting a handle to the VNA and then doing a GPIB clear of the VNA.
*
* The Main Body consists of the VNA SCPI example.
*
* The last step, Cleanup, releases the VNA for front panel control.
*/
#include <stdio.h>
#include <stdlib.h>
/*
* Include the WINDOWS.H and DECL-32.H files. The standard Windows
* header file, WINDOWS.H, contains definitions used by DECL-32.H and
* DECL-32.H contains prototypes for the NI GPIB routines and constants.
*/
#include <windows.h>
#include "decl-32.h"
#define ERRMSGSIZE 1024 // Maximum size of SCPI command string
#define ARRAYSIZE 1024 // Size of read buffer
#define BDINDEX 0 // Board Index of GPIB board
#define PRIMARY_ADDR_OF_PNA 16 // GPIB address of VNA
#define NO_SECONDARY_ADDR 0 // VNA has no Secondary address
#define TIMEOUT T10s // Timeout value = 10 seconds
#define EOTMODE 1 // Enable the END message
#define EOSMODE 0 // Disable the EOS mode
int pna;
char ValueStr[ARRAYSIZE + 1];
char ErrorMnemonic[21][5] = {"EDVR", "ECIC", "ENOL", "EADR", "EARG",
"ESAC", "EABO", "ENEB", "EDMA", "",
"EOIP", "ECAP", "EFSO", "", "EBUS",
"ESTB", "ESRQ", "", "", "", "ETAB"};
void GPIBWrite(char* SCPIcmd);
char *GPIBRead(void);
void GPIBCleanup(int Dev, char* ErrorMsg);
int main()
{
char *opc;
char *result;
char *value;
/*
* =========================================
* INITIALIZATION SECTION
* =========================================
*/
/*
* The application brings the VNA online using ibdev. A device handle,VNA, is returned and is used in all subsequent calls to the VNA.
*/
pna = ibdev(BDINDEX, PRIMARY_ADDR_OF_PNA, NO_SECONDARY_ADDR,
TIMEOUT, EOTMODE, EOSMODE);
if (ibsta & ERR)
{
printf("Unable to open handle to PNA/nibsta = 0x%x iberr = %d/n",
ibsta, iberr);
return 1;
}
/*
* Do a GPIB Clear of the VNA. If the error bit ERR is set in ibsta, call GPIBCleanup with an error message.
*/
ibclr (pna);
if (ibsta & ERR)
{
GPIBCleanup(pna, "Unable to perform GPIB clear of the PNA");
return 1;
}
/*
* =========================================
* MAIN BODY SECTION
* =========================================
*/
// Reset the analyzer to instrument preset
GPIBWrite("SYSTem:FPRESET");
// Create S11 measurement
GPIBWrite("CALCulate1:PARameter:DEFine:EXT 'My_S11',S11");
// Turn on Window #1
GPIBWrite("DISPlay:WINDow1:STATe ON");
// Put a trace (Trace #1) into Window #1 and 'feed' it from the measurement
GPIBWrite("DISPlay:WINDow1:TRACe1:FEED 'My_S11'");
// Setup the channel for single sweep trigger
GPIBWrite("INITiate1:CONTinuous OFF;*OPC?");
opc = GPIBRead();
GPIBWrite("SENSe1:SWEep:TRIGger:POINt OFF");
// Set channel parameters
GPIBWrite("SENSe1:SWEep:POINts 11");
GPIBWrite("SENSe1:FREQuency:STARt 1000000000");
GPIBWrite("SENSe1:FREQuency:STOP 2000000000");
// Send a trigger to initiate a single sweep
GPIBWrite("INITiate1;*OPC?");
opc = GPIBRead();
// Must select the measurement before we can read the data
GPIBWrite("CALCulate1:PARameter:SELect 'My_S11'");
// Read the measurement data into the "result" string variable
GPIBWrite("FORMat ASCII");
GPIBWrite("CALCulate1:DATA? FDATA");
result = GPIBRead();
// Print the data to the display console window
printf("S11(dB) - Visual C++ SCPI Example for PNA/n/n");
value = strtok(result, ",");
while (value != NULL)
{
printf("%s/n", value);
value = strtok(NULL, ",");
}
/*
* =========================================
* CLEANUP SECTION
* =========================================
*/
/* The VNA is returned to front panel control. */
ibonl(pna, 0);
return 0;
}
/*
* Write to the VNA
*/
void GPIBWrite(char* SCPIcmd)
{
int length;
char ErrorMsg[ERRMSGSIZE + 1];
length = strlen(SCPIcmd) ;
ibwrt (pna, SCPIcmd, length);
if (ibsta & ERR)
{
strcpy(ErrorMsg, "Unable to write this command to PNA:/n");
strcat(ErrorMsg, SCPIcmd);
GPIBCleanup(pna, ErrorMsg);
exit(1);
}
}
/*
* Read from the VNA
*/
char* GPIBRead(void)
{
ibrd (pna, ValueStr, ARRAYSIZE);
if (ibsta & ERR)
{
GPIBCleanup(pna, "Unable to read from the PNA");
exit(1);
}
else
return ValueStr;
}
/*
* After each GPIB call, the application checks whether the call succeeded. If an NI-488.2 call fails, the GPIB driver sets the corresponding bit in the global status variable. If the call failed, this procedure prints an error message, takes the VNA offline and exits.
*/
void GPIBCleanup(int Dev, char* ErrorMsg)
{
printf("Error : %s/nibsta = 0x%x iberr = %d (%s)/n",
ErrorMsg, ibsta, iberr, ErrorMnemonic[iberr]);
if (Dev != -1)
{
printf("Cleanup: Returning PNA to front panel control/n");
ibonl (Dev, 0);
}
}