Pot signal becomes erratic when power is supplied to drivers

I’ve been working on my 2 dof rig and trying to test the motors and drivers
I’m using 2 ibt2 with adruino uno r3 and 2 1500wat 24v psu
When I start smc everything is as it should be. Pot signals are solid lines.
When I supply power to the motors the pot signals become slightly noisy and do not produce a solid line when left in position.
When changing the settings to test motor movement (motors move correctly) the erratic signal makes the motors oscillate back and forth with very small movements when the pot is recentered as they are moving to the unstable signal of the pot.
When I turn the power off to the motors the pot signal becomes stable and solid.
I’ve tried adjusting all the settings in smc to reduce this affect with limited success.
I can reduce the noise to a point but it only effects the motor movement and doesn’t completely eliminate the noise and effect and the pot signal stays noisy constantly until the psu are powered off

Sounds like noise. Did the pots cost more than 25 cents? Are the wires to the pots anywhere near the motor wires? Are they routed near the motors?

They are cheap basic pots, 10 for like $10
I have solved the problem by adding a 10nF ceramic capacitor to the pots ground and wiper poles. This stopped the erratic motor motion but the signal was still slightly noisy from a lack of shielding
I shielded the pot and bit of wires extending out of the casing with electrical tape and noise cleared up
I also noticed the pots where picking up signals when being touched is what led me to try it and it fixed the issue

Great! I actually have a low pass filter on my inputs mostly because I use a Hall Effect transducer which outputs a PWM signal but also because it lets me be lazy about the wiring.

A low pass filter also has a resister in addition to the cap. The values are hardly relevant since you only care about a very low frequency.

The capacitor fixed the majority of the feedback noise but a small amount was still present, I added a filter code to the smc.ino to filter out the rest.
https://www.electroniclinic.com/arduino-analog-signal-filter-analog-sensor-value-fluctuates-a-lot/
I used the short simple code after testing on a print sketch to verify it helped.

As I'm not proficient with coding, I would very much like to see the changes you made to your smc.ino code.

I don’t have access to the pc with the code file atm
What I did was this
Fine the lines in the code that read like this
const int PotInputPin = A5; // User adjustable POT used to scale the motion (if enabled)

int DeadZone1 = 0; // feedback deadzone

click in the empty space be these two commands and hit enter
Then paste this between


int PotData = 0;

int filteredValue = 0; // Initialize filtered value
float alpha = 0.1; // Filter coefficient (0 < alpha < 1)

I left a blank space above this code and below

I don’t know if it’s the ideal place to place it and if there is a better/proper place for it but I haven’t experienced any issues and can confirm that it cleared up the last bit of signal fluctuations
I am an amateur at code and can edit and make changes but I am by no means proficient at creating code.

perhaps someone more experienced can help and determine the best way to implement this filter code into the file for others to benefit as it does clearly clear up the pot signal and eliminate small fluctuations that cause the motors to try and constantly adjust to the small fluctuations of the signal resulting in audible noise of the motor rapidly adjusting position in very small increments resulting in a crackling noise that kind of sounds like bacon frying. Visual inspection of the exposed end of the motor shaft show the shaft rapidly changing directions back and forth as a result of the signal fluctuations

these codes can be found here
https://www.electroniclinic.com/arduino-analog-signal-filter-analog-sensor-value-fluctuates-a-lot/
It is the more simple of the 2 codes and gives the better filtering of the 2 as well

Thank you for your help. I'll give that a try.

here is my smc file with the code installed.
it is set to mode 2

Awesome! Thank you for that.