Visa USB refresher

[gdargaud]

Hello all,

years ago I developped a CVI program that communicates with custom hardware via VISA USB. I no longer use VISA, prefering LibUsb for Linux/Win compatibility. And now someone is trying to install it but I no longer remember how to install that thing (I haven't developped for Windows since then).

Do you need to do something with .inf file ? Install VISA drivers ?

At the time I did build a CVI installer with Visa included. I just rebuilt it using the latest CVI since I had doubts wether the old one would work on Win7. Apparently the VISA device still doesn't work.

We get the following message:

Seeking: USB[0-9]*::0x04D8::?*
Visa Error: Les informations concernant la position sont insuffisantes ou bien soit le périphérique soit la ressource n'est pas présent dans le système.
Warning: no USB VISA device found, . . .

[tstanley]

I assume this is a USB RAW device?  The target PC would need NI-VISA installed, or at the very least the NI-VISA Runtime.  It should have a version at least as new as the version on the development machine used to create the driver and application.  To install the driver you would have to manually point the device in Windows Device manager to the directory with the .inf file.   If the .inf file was created a while ago for Windows 2000/XP you may need to create a new one for Windows Vista/7/8 using the NI-VISA Driver Wizard.  If it installs correctly the device would show up in Device Manager under NI-VISA USB Devices (or similar).  It will also show up in NI-MAX.  

To use the device in CVI you will need to open the device with viOpen(..) the resource string from NI-MAX which would be something like "USB0::0x04D8::0x0001::00000001::RAW", though you can also assign an alias in NI-VISA which can be used to open the deivce.  Hope this helps.

[gdargaud]

OK, thanks. My devel machine is still on XP, and the target in Win8 or something, so the .inf generation might be problematic. I'll point them to you message if the old .inf doesn't work. Maybe they can generate it. Thanks

[tstanley]

The requirments on Windows 8 are a bit more strict than they are for previous versions of Windows.  You may need to restart the Windows 8 machine in unsigned driver mode to get your .inf file to install.  One nice thing about Windows 8 is that once installed you can keep using the unsigned driver whereas in Vista/7 you have to restart in unsigned driver mode everytime you wanted to use the driver.  In order to sign the driver in Windows 8 you have to generate a .cat file and sign it with a certificate.  NI has a pretty good description of how to do that here:

http://digital.ni.com/public.nsf/allkb/36DB8D6AC385052786257A940066A421

Note that this may not be requried if the deployed machine is 32-bit, though I haven't played around wirh 32-bit Windows 8 recently.

[gdargaud]

Thanks, we got the visa driver problem working. Now if only the hardware would work as in the past...