Programming Guide

SIGLENT
SVA1000X Programming Guide 71
/* Find all the USB TMC VISA resources in our system and store the number of resources in the system in
numInstrs.*/
status = viFindRsrc (defaultRM, "USB?*INSTR", &findList, &numInstrs, instrResourceString);
if (status<VI_SUCCESS)
{
printf ("An error occurred while finding resources.\nPress 'Enter' to continue.");
fflush(stdin);
getchar();
viClose (defaultRM);
return status;
}
/** Now we will open VISA sessions to all USB TMC instruments.
* We must use the handle from viOpenDefaultRM and we must
* also use a string that indicates which instrument to open. This
* is called the instrument descriptor. The format for this string
* can be found in the function panel by right clicking on the
* descriptor parameter. After opening a session to the
* device, we will get a handle to the instrument which we
* will use in later VISA functions. The AccessMode and Timeout
* parameters in this function are reserved for future
* functionality. These two parameters are given the value VI_NULL.*/
for (i=0; i<int(numInstrs); i++)
{
if (i> 0)
{ viFindNext (findList, instrResourceString);
} status = viOpen (defaultRM, instrResourceString, VI_NULL, VI_NULL, &instr);
if (status<VI_SUCCESS)
{
printf ("Cannot open a session to the device %d.\n", i+1);
continue;
}
/* * At this point we now have a session open to the USB TMC instrument.
* We will now use the viPrintf function to send the device the string "*IDN?\n",
* asking for the device's identification. */
char * cmmand ="*IDN?\n";
status = viPrintf (instr, cmmand);
if (status<VI_SUCCESS)
{
printf ("Error writing to the device %d.\n", i+1);
status = viClose (instr);
continue;
}
/** Now we will attempt to read back a response from the device to
* the identification query that was sent. We will use the viScanf
* function to acquire the data.
* After the data has been read the response is displayed.*/
status = viScanf(instr, "%t", buffer);
if (status<VI_SUCCESS)
{ printf ("Error reading a response from the device %d.\n", i+1);
}
else
{ printf ("\nDevice %d: %s\n", i+1, buffer);
}status = viClose (instr);
}
/** Now we will close the session to the instrument using
* viClose. This operation frees all system resources. */
status = viClose (defaultRM);
printf("Press 'Enter' to exit.");
fflush(stdin);
getchar();
return 0;
}
int _tmain(int argc, _TCHAR* argv[])
{
Usbtmc_test();
return 0;
}