viOpenDefaultRM fails on USB but not GPIB

[mbrooks]

We are changing over our VXI chassis and power supplies in an application to run over USB instead of GPIB.

I have 2 power supplies and 2 VXI chassis that we've previously used GPIB addressing to communicate.  I've changed these device to USBs.  The power supplies get detected properly by the system as USB measurement devicse and Visa Interactive control recognizes the devices properly. My application succesfully talks to the 2 power supplies.

However, my VXI chassis won't talk USB until I load the latest VXI drivers.  When I do this, I can talk to my VXI chassis but my power supply suddenly gives me a failure on the 

viOpenDefaultRM call, of "The specified configuration doesn't exist, defaults will be used". This is before I've even tried to open the power supply. 

I know the VISA32.dll is being found properly otherwise the4 viOpenDefaultRM would fail with an unresolved reference. What and where is the default Resource Manager? Is this a running service or a dll? 

-thanks,
Michael

[Mr.F]

Hi Micheal,

Is there an error number associated with that error message? Also, are you running Resman in Measurement and Automation Explorer and does that give you errors as well?

Regards,

[mbrooks]

I'm not easily in a position to get the error number again.  I found that the code for viOpenDefaultRM was

 if (viOpenDefaultRM != VI_SUCCESS)

I changed it to

 if (viOpenDefaultRM < VI_SUCCESS) and got a bit further. In the end what I've found is that dropping back to the VISA 3.2  and vxi3.5 got me past this trouble.  I was using VISA 4.2.   So the question now is, is there incompatibility with VISA 4.2 and vxi3.5?

On vacation for the rest of the week.  

-Thanks,

Michael 

[Mr.F]

Hi Micheal,

What operating system are you using? I see that using VISA 3.2 and VXI 3.5 is getting you no errors, and I don’t’ want to cause your system to stop working, but have you considered upgrading to VISA 4.5 and VXI 3.5.2? As far as I could tell the isn’t a particular issue with VXI 3.5 and VISA 4.2, but that particular combination may not have been tested in depth.

[mbrooks]

Matt,

We are using WindowsXP.   I can try upgrading.  Where do I find the latest of both the VISA and VXI

-thanks,

Michael

[Mr.F]

The newest drivers are available for download at ni.com/support click drivers and updates and search for VXI and VISA, and then select a version that is compatible with your operating system.