I am trying to control a motor unit (with its own control circuit and microcontrollers) using Arduino MKR ZERO. The control signals are acquired through a voltage sensor using analogReadFast(A1), which control the motor through the MKR CAN shield. The motor unit is powered by 230V electrical supply.
When the Arduino board was powered by the PC, the system worked totally fine. However, 25Hz noise occurs on the analog input signals (A1) when I powered the Arduino by a power bank instead. The noise disappeared when I turned off the motor unit.
May I ask if anyone knows the reasons for this issue or has any suggestions to fix it? Is it possible if the input signals are affected by the CAN bus?