How should I clear a CANbus (NI-9853) error code?

[Confused CANr]

I am successfully using both ports of a NI-9853 on the cRIO 9104 backplane, unit one port is disconnected.  The disconnected port gives me the error 65538 (Op failed) while the still functionally connected port generates the error 65539 (Input missed 1 or more data points).  I can detect the disconnect using these error codes but I'm not sure what are the best steps to:

 1) Continue to use the connected port

while

 2) Polling the disconnected port to see when it is reconnected

[StephenB · Accepted solution]

It sounds like you have the IO nodes of each port in the same FPGA loop.

If one IO node is failing, it is going to have at least a 4 second timeout before it fails, and the default timeout is 14 seconds (configured in properties). There are two timeouts involved: One is the output timeout, configured by the user in the 'Advanced' dialog box of the module properties dialog, and another is a fixed 4 second timeout in LV-FPGA waiting for a response from the CAN module.

If the nodes are in the same loop, the disconnected port will block the loop over and over causing the still connected port to sample at a crawl. Try moving them to their own loops.

Message Edited by Stephen B on 03-16-2009 10:50 AM

[Confused CANr]

Thanks Stephen...

I did have them in the same loop so I'm trying to make it fit once I split the 2 handlers... Only had 1 slice to work with 😞

I'll let you know as soon as I can test a fitted FPGA.

[Confused CANr]

Thanks Stephen...

Yes splitting the channel read/write into seperate loops seems to have resolved the problem.