Odrive Pro CANbus not working

1

Hi, following the “CAN Bus Guide — ODrive Documentation 0.6.8 documentation” guide i set up the odrive pro, connected a CAN USB Connector “https://www.waveshare.com/wiki/USB-CAN-A” as well as a Oscilloscope, but no signal is send or even generated after completing the guide. The same Setup on an Odrive V3.6 works like a charm. Is there something not mentioned in the guilde?

Greetings, Sebastian Benkel,
(Framework Robotics GmbH)

2

Hi there,

Have you connected CAN_GND to your system star point?

3

We followed the schematic here: “CAN Bus Guide — ODrive Documentation 0.6.8 documentation”. Our Oscilloscope and Logic analyser couldn’t even detect anything resembling a CAN signal, is there a requirement before the odrive starts submitting? we tried a newly flashed odrive as well as one set up with a motor.
Thanks for your reply.

4

Just to confirm - the CAN_GND is connected to DC- at a single point, correct? This is a requirement for CAN to work. Note that explicitly this isn’t just connecting CAN_GND to the ground of your scope/logic analyzer, but DC- as well.

And the ODrive is running firmware v0.6.8?

After setting the CAN parameters in the GUI/ODrivetool, the ODrive’s configuration was saved (with odrv0.save_configuration() in ODrivetool and the save_configuration button in the GUI inspector)?

5

Yes, we used the ground from FEEDBACK IO, after checking that is has no resistance to ground on the powersource(Pin 11). Should be the like this:
Odrive wiring

(GND3 has no resinstance to power supply GND)

We tried two newly updated Odrive Pro with 0.6.8, without a motor, and one odrive pro we prepared last year, so Odrive 0.6.5.

When trying to send a message from another CAN device(Raspberry Pi shield) we got this weird inverted signal:

image
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while the same Pi shield got readable messages from Odrive 3.6 that looked like this:
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6

So CAN_GND is connected to GND on FEEDBACK_IO? While there isn’t steady-state resistance, there’s filtering components between FEEDBACK_IO GND and DC-. There’s a good chance that’s what’s causing the strange inverted readings you’re getting.

Just checking - both sides of the bus have a 120 ohm termination resistor? Is the ODrive powered? The ODrive Pro requires either power from DC+/DC- (above 12V) or an external 12V input over CAN_12V/CAN_GND for the CAN transceiver to come online.

7

Thank you for your help, we found a faulty cable used for ground :face_with_peeking_eye:. Now everything is working as expected.

8

That would do it! Glad to hear it’s working out!