Uart arduino timing out

[kragon]

Hello,

I’m getting an issue with the uart between two odrives and an Arduino mega.

After a trigger/event all serial communication to one or both odrives results in a timeout.

The event that triggers it has something to do with reading data while the motors are enabled and moving, but I can’t pin down an exact cause.

• The only way to re-establish communication is by cycling power to the odrives.
• The odrive can be read from or the motors controlled with only occasional issues, but not both.
• the odrive and Arduino are connected with short jumper wires that are as far as reasonably practical from everything noisy.
• Vibration, either from myself or the motors doesn’t seem to influence anything.
• temporarily disconnecting rx/tx doesn’t cause any issue outside the obvious loss of data.

Anyone got any ideas?

[Wetmelon]

Noise or improper grounding. Make sure all of the logic grounds are grounded on J3. You may have trouble with communication anyway if you’re powering everything off the same battery…

[kragon]

thanks for the reply.
the arduino and odrive have a common ground.
the arduino is powered from a seperate sorce to the odrive. (separate battery or pc)
i cant do much more about noise unless your recommending a shielded cable for the ~100mm between boards?

how reliable is the step/dir input method?
does anyone have code i can work off of that’s more feature complete than the example code?

[kragon]

replaced the serial line with shielded cable and grounded the heat-sink. seems to have solved the issue.
thanks for pointing it out, wouldn’t have thought it would be that noisy at such low speeds/power on such a short cable.
its all happy running from a common battery now too.

[danbowen95]

Hi,

I think i am experiencing the same issues as you. I’ve got some shielded cable on order which i’m hoping should help.

Would it also be safe/helpful to join the two grounds of the different PSUs? Here’s what the circuit set up looks like:

Thanks!
Dan