The absolute value encoder is a sensor that directly outputs digital quantities. There are several concentric code tracks along the radial direction on its circular code disc. Each track is composed of light-transmissive and opaque sectors. The number of sectors is a double relationship. The number of code channels on the code disc is the number of binary digits. On one side of the code disc is the light source, and the other side corresponds to each code track. There is a photosensitive element; when the code disc is in different When in position, each photosensitive element converts a corresponding level signal according to whether it receives light or not to form a binary number