CAN wiring with separate PSU for each ODrive

Hi. Could someone help me with correct wire connections for case when each ODrive is powered with its own PSU. Entry point for CAN network will be isolated CAN to USB board(CANable Pro)

Do not want tu burn any of components

Are you using ODrive Pro, ODrive S1, or ODrive v3?

V3.6 version

For ODrive v3.6:

1 Like

CAN does not require ground to function. The H and L wires are differential, meaning that the receiver only needs to measure the difference between those two and doesn’t care about the difference to ground.

However, there is a limit on the maximum difference between H, L and ground. That’s because nobody builds their CAN interface to handle a thousand volts - a spark will simply jump over the circuit board to ground. You will find that your “isolated” device has a limit somewhere buried in the specifications. In practical terms, you really would never want that difference to exceed a hundred volts. It would not be hard to accidentally exceed that difference if your two power supplies are incorrectly connected to mains power - they work fine on their own but a spark might jump when you connect grounds together.

That’s why most CAN cables have 3 wires. They need to tie the grounds together to stop sparks. If there was a significant fault in the power supplies, that’s going to burn out that skinny wire pretty quickly and you will go looking for the problem. It might set fire to other things though.

I would start with a “power ground”. Some thick wire or a single grounding point that all the power supplies are grounded to. Then you can use 3-wire CAN cables or 2 wires, whatever you prefer.