Issue Details

When a USB or SD flash drive is removed and replaced the controller keeps assigning them a new letter instead of reusing the old ones (letter U: for the first drive, V: for the second, and so on).

This causes issues when the controller switches to storing data on the local drive when it runs out of letters to assign.

 

Solution

There are a few suggestions to try and resolve this issue:

• Reboot the controller.
• Update the controller to the newest firmware. Currently firmware updates are distributed with the specific device driver (e.g. a cRIO-9068 will have any firmware updates distributed with the NI CompactRIO Driver).
• Ensure the USB is directly connected (without USB Hubs etc.)
• Check the file format and size is compatible. All NI Real-Time devices support FAT32, and this format is recommended for ease of transfer to Windows. FAT16 has a 4GB limit on partition size, whereas FAT32 has a 2TB limit on partition size. OS specific compatibilities are below:
  • For PharLap systems, external USB drives can use either FAT32 or Reliance file formats.
  • On VxWorks, the only supported format is FAT32.
  • For LinuxRT, external USB drives should be formatted as be FAT32. For raw NAND devices UBIFS is accepted.

Additional Information

A suggested workaround:

Save the name of each USB to an INI file present in a consistent location in the USB. Use an INI file check in order to identify the USB drives.