6032A operation under LWCVI

[Greg Knight]

I have a 6032A power supply (GPIB Address 3) and an NI-GPIB (GPIB Address 0) and both show up under NI measurement and explorer under Devices and interfaces.  I downloaded the driver for the 6032A and ran the following simple function to see if it would reset:

                    hpxxxa_init ("GPIB::3", VI_ON, VI_ON, 2, ViSession_ID);

The program compiles.  Vi Session_ID is defined in main as a ViPSession, the 6032A powers up as address 3, and the parameter 2 in the above function indicates 6032A.

I get a fatal run time error --> Null pointer to a Library function.  The file that it points to is HP6XXXA.c.  The function is

if ((hp6xxxa_status = viOpen (rmSession, resourceName, VI_NULL< VI_NULL< instrSession)) <0)

It points to the parameter instrSession as being the problem.

Your help is most appreciated to get me going.  Please respond by email to greg_k_knight@raytheon.com

[markus kossmann · Accepted solution]

The last parameter is intended to be an output parameter and expects a pointer pointing to allocated memory.  

Try

[...] 

ViSession  ViSession_ID

[...]

hpxxxa_init ("GPIB::3", VI_ON, VI_ON, 2, &ViSession_ID);

[...] 

instead.