Relay Circuit Interfere with RF signal - How to improve?
From the comments, I gather I hit the right spot.

The problem lies in having a common ground between the contoller and the motors.

The idea behind optocouplers is to be able to send control signals with out the noise of the high power device causing problems to the controller.

What's happening is that switching the motor causes voltage surges on the ground.   Given that you are using 180VDC, those surges can be pretty large.  Switching motors can cause problems even at lower voltages (the spikes can easily be many times the supply voltage.) Since you are using such a high voltage, I would assume thhe motor is large - the larger the motor, the more energy it will store, and the more powerful the spikes will be.




Power the controller from its own 3.3V power supply.
Use the optocouplers to transmit the control signals to the motor.
Separate the motor ground from the controller ground.


That should improve things greatly.