CWVisa Open Failure

[EXS]

I am using CWVisa in several applications to search for installed resources in a system.  In fact, I am using most of the example code in the FindResource Method documentation to accomplish this.  It works quite well on several systems running Windows2000 SP4 and XP-Pro SP2. 

When installed on another system running Windows2000 SP4, the applications fail from the get-go.  Tracing VISA traffic using NI-SPY shows that ViOpenDefaultRM gets a 0x3FFF0077 status and the subsequent viOpen function fails with a 0xBFFF0011 status.  I made sure that the drivers and DLLs listed for CWVisa in the NI app note "Manually Installing your Program and Program Files" were installed and registered.  Any ideas on what's wrong would be appreciated. 

[MichaelChaney]

Hi EXS,

If your program is able to run sucessfully on other systems, then I doubt there's anything wrong with your code.  I've seen this error before with bad installations of VISA.  The explanation of the error is "The specified configuration either does not exist or could not be loaded. VISA-specified defaults will be used." 

One thing you can try is to open Measurement & Automation Explorer (MAX) while NI-Spy is capturing.  MAX calls ViOpenDefaultRM imediately upon launch to get a list of available resources.  See if you get this error when launching MAX and expanding Devices and Interfaces.  If you do get an error, then this indicates a bad installation of VISA.  Try uninstalling and reinstalling NI-VISA making sure that support for Measurement Studio is selected.

If you don't get an error when launching MAX, double check the resources and make sure they are identical to you other systems.  Verify that resource names and addresses are the same.  I hope this information helps.