Is also called photoelectric photoelectric encoder angular position sensor, is a collection of optical, mechanical and electrical/speed sensor in the integration of digital Angle, it adopts photoelectric technology will shaft Angle information is converted into digital signals, after connected with the computer and display device which can realize dynamic measurement and real-time control. It includes optical technology, precision processing technology, electronic technology, etc. , its technology link directly affects the comprehensive performance of the encoder. Compared with other similar USES sensors, it has high precision, wide measurement range, small volume, light quality, and the advantages of reliable operation, easy to maintain, are widely used in the ac servo motor speed and position detection.