Encoders are generally divided into incremental and absolute encoders, and they have the biggest difference: in the case of incremental encoders, the position is determined by the number of pulses calculated from the zero mark, while the position of absolute encoders is Determined by the reading of the output code. In a circle, the reading of the output code of each position is unique; therefore, when the power is disconnected, the absolute encoder is not separated from the actual position. If the power is turned on again, the position reading is still current and valid; unlike incremental encoders, you must search for the zero mark.