What are the types of encoders for servo motors?

Encoder is a device that converts angular displacement or linear displacement into electrical signals. The former becomes a code wheel and the latter is called a yardstick. Encoders can be divided into contact type and non-contact type according to the read mode. The contact type uses an electric brush to output. A brush touches the conductive area or the insulating area to indicate whether the status of the code is "1" or "0"; the non-contact type receiving sensitive element is a photosensitive element or a magnetic sensitive element. The light-transmitting area and the opaque area indicate whether the state of the code is "1" or "0". According to the working principle, encoders can be divided into two types: incremental and absolute. The incremental encoder converts the displacement into a periodic electric signal, and then converts this electric signal into a counting pulse, and the number of pulses is used to indicate the magnitude of the displacement. Each position of the absolute encoder corresponds to a certain digital code, so its indication is only related to the start and end positions of the measurement, and has nothing to do with the middle process of the measurement.