The solid shaft encoder is connected to the motor shaft by means of a solid shaft with the aid of a flexible coupling and an external flange. This type of mounting coaxiality is lower, and the increased coupling and flange require more installation space, often in low resolution and low precision applications.

Encoder can be divided into absolute encoder and incremental encoder. Incremental encoder is relatively easier in realizing its function than absolute encoder. Its cost is lower than absolute encoder. The measuring range of incremental optical encoder is one turn(360 degree). After 360 degree, it will start from 0 again. Optical sensor has higher accuracy than magnetic encoder. The optical glass can provide the accurate position feedback.