How to connect CAN-gnd?

Hi

In the schematic in:

CAN Bus Guide — ODrive Documentation 0.6.11 documentation

It it shown that CAN-gnd should not be connected to common ground.

However it seems that is the case at the picture in:

Controlling ODrive from an Arduino via CAN — ODrive Documentation 0.6.11 documentation

What is correct?

I find the setup rather sensitive and suddently looses its calibration etc.

Hi! On the ODrive Micro and S1, CAN is referenced to the ODrive’s DC-, and the CAN connectors are just used for a convenient daisy-chain (the CAN GND is internally not connected, only passed between the connectors). On the ODrive Pro, CAN is referenced to CAN_GND (which must be connected to the system DC- at some point). Typically, you want to star logic and power grounds at a single location. In the Arduino docs, the passthrough CAN_GND is used as an easy way to get the Arduino on the same ground domain as the S1 – another option would be to just run a wire from Arduino GND to the S1 DC-, or preferably to do so near your power supply / battery / power distribution block. Note that it does show to connect grounds in the CAN bus guide:

I find the setup rather sensitive and suddently looses its calibration etc.

Hmm, that’s quite interesting. Can you share more? Which ODrive, encoder, motor, etc? That generally sounds more like an encoder issue.