USB Loop Back Test setup with NI-VISA 3.0?

[Justox]

Can Labview be setup to do a Loop Back test using USB? I'm running one USB output to a 4-Port Hub which then returns back to the PC. Since the hub is not seen as a device can Labview still be setup to recognize the USB ports to output and input information?

[ScottieB]

Hello,

It seems that you are trying to test LabVIEW to VISA support by connecting 2 USB ports on your computer to a USB Hub, sending data out one USB port and receiving it on the other.

This is not a supported configuration with NI-VISA, the underlying communications protocol that will support USB in LabVIEW. Generally, to communicate with a device via USB you need to generate an INF file for that device that specifies VISA as the driver using the VISA Driver Development Wizard which will require the Vendor ID and Product ID from the device to which you will eventually communicate.

More information about NI-VISA and USB Support can be found in the following KB's:

http://zone.ni.com/devzone/conceptd.nsf/webmain/6792BAB18242082786256DD7006B6416?opendocume
nt

http://digital.ni.com/public.nsf/websearch/044FA220F32774ED86256DB3005850CA?OpenDocument

Scott B.
National Instruments
Applications Engineer