Introduction to Encoders

Encoders are devices that are used in the closed loop control of motors. Encoders provide the control system the feedback on where the motor is positioned. Encoders can be linear, or radial. If the encoder is physically connected to the motor shaft in some way, then the encoder is generally circular containing some type of transparency that would provide a pulse if turned. The pulse is generated by a light on one side of the encoder and a sensor on the other side of the encoder. If the encoder is not physically connected to the motor shaft, then the encoder may be a linear strip (commonly called a code strip). The light and sensor would be connected near the motor and the code strip would be tied the extremes of where the motor will travel.