Pendulum CNT-90 - USB Communication (Ex. #4)

USB Communication (Ex. #4)
#include “stdio.h”
#include “visa.h”
#include <time.h>
#define MAX_CNT 200
void Sleep( clock_t Wait );
int main(void)
{
ViStatus Status; // For checking errors
ViUInt32 RetCount; // Return count from string I/O
ViChar Buffer[MAX_CNT]; // Buffer for string I/O
ViFindList fList;
ViChar Desc[VI_FIND_BUFLEN];
ViUInt32 numInstrs;
ViSession defaultRM, Instr;
inti=0;
// Begin by initializing the system
Status = viOpenDefaultRM(&defaultRM);
if (Status < VI_SUCCESS) {
printf (“Failed to initialise NI-VISA system.\n”);
return -1;
}
// Look for something made by Pendulum
Status = viFindRsrc(defaultRM,
“USB?*INSTR{VI_ATTR_MANF_ID==0x14EB}”,
&fList, &numInstrs, Desc);
if (Status < VI_SUCCESS) {
printf (“No matching instruments found.\n”);
return -1;
}
// Open communication with GPIB Device
Status = viOpen(defaultRM, Desc, VI_NULL, VI_NULL, &Instr);
if (Status < VI_SUCCESS) {
printf (“Cannot communicate with instrument.\n”);
return -1;
}
// Set the timeout for message-based communication
Status = viSetAttribute(Instr, VI_ATTR_TMO_VALUE, 1000);
// Ask the device for identification
Programming Examples
USB Communication (Ex. #4) 4-11