UNI-T UTG900E Series - Page 26

Programming Manual UTG900E Series
Instruments.uni-trend.com
26 / 41
* results using the write and read functions.
* Open Resource Manager
* Open VISA Session to an Instrument
* Write the Identification Query Using viPrintf
* Try to Read a Response With viScanf
* Close the VISA Session*/
ViSession defaultRM;
ViSession instr;
ViUInt32 numInstrs;
ViFindList findList;
ViStatus status;
char instrResourceString[VI_FIND_BUFLEN];
unsigned char buffer[100];
int i;
status = viOpenDefaultRM(&defaultRM);
if (status < VI_SUCCESS)
{
printf("Could not open a session to the VISA Resource Manager!\n");
return status;
}
/*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);