Rotary encoders are electromechanical devices that provide feedback on the rotational movement of an axle or shaft. Comprising two parts – a reader and a scale – rotary encoders typically accomplish this task either by either “absolute encoding” or “incremental encoding”: Absolute encoders measure the precise angular position of the reader relative to the scale, while incremental encoders sense the motion of the scale relative to the reader.1
Whether incremental or absolute, rotary encoders are vital in virtually all automation or robotics applications that involve precisely controlled rotational movement. Conveyor systems, for example, commonly use rotary encoders on drive wheels to control the speed and position of the belt. Likewise, rotary encoders are used in elevators to ensure that elevator cars start and stop smoothly and in the right place. Any rotational robotic joints will also contain rotary encoders to ensure movement is accurately controlled.