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Concept testing of Low-Speed/Fault-Tolerant CAN

Hi,

I have a board on the way where I am going to test LS/FT CAN. In preparation, Im trying to get a loop traffic with a 2 port PXI-8513 software selectable CAN transceiver and the CAN breakout box. With some trial and error I managed to get LS/FT going with the XNET library, but encountered some trouble when testing the different failure modes.

Currently I have the following LS/FT modes working.

  • Normal traffic (simple frames) (Confirmed in MAX Bus monitor)
  • CAN_H shorted to ground (no problems) (Confirmed in MAX Bus monitor)
  • CAN_L shorted to ground (termination can only be connected on the receiving side (?)) (Same termination issue in MAX Bus monitor)

I want to test shoring them individually to 12V and also shorting them together so that I can continue writing the tests.

From what I understand the bus should still be functioning under these conditions.

I am scoping the signals and decoding them. I can see that the signals somewhat behave as expected, but the transceiver doesn't seem to pick it up. Its been difficult to find examples on how this is supposed to look. If anyone have any ideas, I would appreciate it greatly.

 

Maybe there is some termination issue? Do I need more than two nodes? I am using the internal termination on each node (PXI-8513)


Here are some scope-shots of the frames.
http://imgur.com/a/Wmsbd

 

Here's my LV code. Im just sending out on one and receiving on the other. Maybe there are some properties that I have missed?

http://imgur.com/a/pjoBV

Best regards,
Erik

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I made a new cable and now everything works as expected! 

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