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USB Device Not Recognized by NI-VISA on NI Linux Real-Time Target

Updated Jan 12, 2023

Reported In

Software

  • LabVIEW Real-Time Module

Driver

  • NI-VISA

Operating System

  • NI Linux Real-Time

Other

Secure Shell (SSH Protocol)

Issue Details

NI-VISA does not recognize my USB device when I plug it into a NI Linux Real-Time target:
  • It doesn't show up under my Real-Time target in NI-MAX
  • I cannot select it as an option for my VISA resource in LabVIEW 
What can I do to resolve this issue?

Solution

The NI Linux Real-Time OS may already have a driver for your particular device that prevents NI-VISA from claiming the device. Complete the following steps to disassociate a driver from a particular device:
  1. Connect to the target using Secure Shell (SSH Protocol). This can be accessed from Windows using any terminal command such as PuTTY.
  2. Login as an administrator.
  3. With the device unplugged, run lsmod
  4. Plug the device back in
  5. Run lsmod again
  6. If Linux recognizes the device with its own driver, a new module will show up under the second iteration of lsmod
  7. Enter the command rmmod <driver name> . For a CDC ACM class device, this command would be rmmod cdc-acm.
If the USB device does not load a new module with lsmod, there is no driver and NI-VISA should be able to connect and recognize your USB device.

Additional Information

Power cycling the device or unplugging and re-plugging the USB device will reload the driver module, causing the same conflict with NI-VISA. You will have to re-run the rmmod command in each of these cases, either manually or programmatically . 

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