FlexRay Interface Does Not Respond After the Bus Sleeps

Updated Apr 3, 2023

Reported In


  • PXI-8517
  • PCI-8517


  • VeriStand



Issue Details

  • My test halts the FlexRay bus and then wakes up the bus again, but my XNET card does not respond after.
  • The values on my FlexRay channels in VeriStand are not changing.
  • If my XNET FlexRay card gets disconnected, I have to redeploy my VeriStand project to use it again.
  • The red LEDs flash on the FlexRay interface 


To help identify the status of your NI-XNET card, check the LED status of the interface to understand what the card is doing.

Below are some steps specific to VeriStand, but for more general troubleshooting of FlexRay, please refer to the NI-XNET Troubleshooting Guide.

The FlexRay implementation in VeriStand does not have the bus recovery built-in once an established connection has been broken or the bus has entered the POC:Halt state. There are 2 ways to recover the bus once it has reached a halted state in VeriStand: 
  • Use the example FlexRay Sleep custom device attached to this Knowledgebase
  • Make your own custom device that implements a bus reset or logic to manage the state transitions back from POC:Halt state to POC:Normal Active. Please refer to the FlexRay state diagram below.
FlexRay State Diagram

Additional Information

The FlexRay Sleep custom device calls the NI-XNET Stop and NI-XNET Start functions to stop and start the interface referenced. Be aware that this will reset the whole interface and related sessions.