How Servo Motors are used in Process Control

Servo motors are continuous motion mechanisms that use feedback signals to provide position and velocity control in a closed loop system.

Servo motors can rotate to a given position be stopped and reversed. The angular position and speed can be precisely controlled by a servo loop, which uses feedback from the output to the input.  For example the position of the output shaft is monitored by a potentiometer which then provides an analog feedback voltage to the control electronics (in digital system, an encoding disc would be used).

The control electronics uses the feedback information to power the output motor, and stop it in any desired position or reverse the motor.