Cytron Motor Controller goes Full speed if MCU (ESP) loses power

I have what I consider a high risk problem.
I am using a Cytron Motor Controller MDDS30 controlled by an ESP8266, if the power is lost to the ESP the motor controller goes Full speed.
This is a mobile robot!

I had expected the motors to simply stop as it is no longer receiving the PWM signal.

Any advice, suggestions etc would be greatly appreciated. Thanks.

Hello @JDParr and welcome to the RobotShop forum,

This might be because of the settings you have configured for the controller.

For reference:


Motor stops when the input signal is 2.5V. Motor moves in one direction when the input is < 2.5V (0 - 2.5V) and in another direction when the input is > 2.5V (2.5 - 5V).


AN1 and AN2 controls the speed of the motor. Motor stops when the input is 0V and run at full speed when the input is 5V. IN1 and IN2 is digital inputs and it controls the direction of the motor respectively.

You are probably using the Locked Anti-phase mode, however, if you want the motors to stop when the ESP8266 is not powered the Signed Magnitude mode might be a better option.