Rotary Optical Encoder is a sensor, which converts rotary motion or position to electronic pulse numbers for phase change, speed and position detection. It is also used to detect the speed, position, angle, distance and counts information relating to mechanical machine.

Major applications include main hoist of crane (crane contro), elevator, industry sewing machine, textile machine, storage equipent, medical treatment related machine and servo motor. Therefore, Rotary Optical Encoder is a very important device in industrial automation field.