This content is not available in your preferred language.

The content is shown in another available language. Your browser may include features that can help translate the text.

USB Connection Keeps Disconnecting

Updated May 3, 2024

Reported In


  • CompactRIO Chassis
  • PXI Chassis
  • myRIO Student Embedded Device
  • Stratom myRIO X-HUB Adapter

Issue Details

  • I have a USB cDAQ Chassis connected to a USB hub which is plugged into a PXI controller. The cDAQ disconnects randomly after days or weeks of continuous operation. What could be the cause of this issue?
  • I have a myRIO connected to my computer using a 10 m USB cable. Sometimes I cannot connect to my myRIO. What can I do to improve the situation?
  • I want to expand the one USB port on my myRIO using external USB hubs. What should I watch for?


There are several caveats you can run into when using USB:
  • Respect the maximum specified length for a USB cable of 5 meters for high-speed data rates.
  • If possible use externally-powered USB hubs.
  • Use shielded USB cables to minimize interference from surrounding equipment or cables.
  • Do not use USB extension cables, they often break connections due to signal reflections.
  • Do not use USB signal repeaters, use self-powered USB hubs instead.
  • Do not daisy-chain more than five USB hubs serially.
  • Take into account the bandwidth of your USB port. Depending on how many devices you connect to it you might run into its limit.