Encoder working principle

A photoelectric code disc with an axis in the center, on which there are circular and dark engraved lines, is read by photoelectric transmitter and receiver, and obtains four sets of sine wave signals combined into A, B, C, D, each sine wave A phase difference of 90 degrees (360 degrees relative to a cycle), the C and D signals are reversed and superimposed on the A and B phases to enhance the stable signal; in addition, a Z-phase pulse is output every revolution to represent the zero reference Bit.

　　 Since A and B phases differ by 90 degrees, the encoder's forward and reverse rotation can be judged by comparing the A phase or the B phase. The zero reference position of the encoder can be obtained through the zero pulse. The materials of the encoder code disc are glass, metal, plastic. The glass code disc is deposited on the glass with very thin scribe lines, which has good thermal stability and high precision. The metal code disc is directly engraved with through and impassable lines and is not fragile. However, due to the certain thickness of metal, the accuracy is limited, and its thermal stability is one order of magnitude worse than that of glass. Plastic code discs are economical, and their cost is low, but accuracy, thermal stability, and life are worse. .

　　 Resolution—The number of open or dark engraved lines provided by the encoder per 360 degree rotation is called resolution, which is also called resolution division, or directly called the number of lines, generally 5 to 10,000 lines per revolution.