NI-XNET Port LED Blinks Red

Updated Jun 16, 2021

Reported In


  • USB-8501
  • USB-8502
  • USB-8506
  • PCI-8511
  • PCI-8512
  • PCI-8513
  • PCI-8516
  • PCI-8517
  • PCIe-8510
  • PXI-8511
  • PXI-8512
  • PXI-8513
  • PXI-8516
  • PXI-8517
  • PXIe-8510
  • TRC-8542
  • TRC-8543
  • TRC-8546
  • NI-9861
  • NI-9862
  • NI-9866


  • LabVIEW
  • VeriStand



Issue Details

The port LED on my XNET device when I start the communication blinks red. 


The port LED blinks red if a NI-XNET catastrophic error occurs as indicated in the NI-XNET manual.

There are several reason for this issue:
  1. Verify that the cabling is working properly.​
  2. Check the termination resistors section in the device Getting Started Guide to verify that the termination resistors match the nominal impedance of the CAN cable. The termination resistance may become out of tolerance to support both devices.
  3. Monitor the traffic on your bus using the NI-XNET Bus Monitor and ensure that Bus Error Frames are enabled in the Interface and Database Settings. You may see a Bus Error Frame which will have ERR as the frame type. You can reference the data in the frame payload against the Bus Error Frame chart  on page 4-553 of the NI-XNET Manual to see the type of Bus Error that is occurring. If you can using CAN FD, it could be related to Error or Incorrect Frames When Using NI-XNET in CAN FD & BRS .
  4. Verify that you are writing the right XNET messages.
  5. Perform a loop-back test by using the Loopback, located in the NI Example Finder in Hardware Input and Output >> CAN >> NI-XNET >> Loopback Test to verify correct cabling.
  6. If none of the above helps, contact NI Support.