Encoder/Power noise feedback

I have worked to recreate the Hoverboard example given here:


and have worked to follow it closely.

Have another system working to measure the position (Pos) and velocity (Vel), so it is tapped into the encoder lines and share them with the Odrive.
To limit any kind of loading of the other system on the Odrive I have 11.3k resistors inline with what is split off for that system.

I am able to read Pos and Vel with the Odrive on and motors in idle.
As soon as the Odrive engages a Motor I’m not able to read Pos anymore (it gives me ~zero) while I’m still able to get Vel

looking at the encoder lines I can see nice clean pulses with the exception of a 2volt peak-to-peak ringing type of noise that happens once every 5 seconds for about 50ms.

My 2 questions:
What is causing the ringing?
The ringing does not seem, to me anyway, to be enough to stop from reading Pos, so what is?

I have been working on this for a few days now and I can’t seem to work it out.
I have tried replacing the Odrive but the noise and Pos issue are still present.
There are no errors reported on the Odrive.
The ringing can be observed out on the Odrive DC input. where the battery is feeding the Odrive.

Any help would be awesome, thanks for your time.
I can provide pictures if needed.

Can you post some pictures? I’m curious to see what this looks like. It is known that ODrive can really dump a lot of noise into the encoder lines - they tend to run next to the phase wires, and ODrive is running quite a lot of current. PWM frequency is 24kHz, btw. Use shielded, twisted wire for everything and it’ll help.