Using PWM allows precise current control in the windings. Hence, the output torque, which is linearly proportional to the average winding current, can be correctly controlled in coreless motors.

This DC servo motor controller can also be used with an external potentiometer or the integrated on board potentiometer. For applications with existing PWM signals available this can also be used ...

What Are PWM Pins? The Arduino Mega's PWM pins are digital output pins located on D2 to D13 and D44 to D46, coming to a total of 15.

The machine uses a ‘grbl’ controller, which has an Arduino-based circuit that includes multiple outputs, including a powerful 24V pwm signal that is generally used to drive a 60-80W spindle motor.