What kinds of encoders are commonly used in motors?

First, incremental encoder

Directly use the principle of photoelectric conversion to output three sets of square wave pulse A, B and Z phases. The phase difference between the two groups of A and B is 90o, which can conveniently determine the direction of rotation; one pulse per revolution of the Z phase is used for the positioning of the reference point. The advantages are as follows: the principle structure is simple, the average mechanical life can be more than tens of thousands of hours, the anti-interference ability is strong, the reliability is high, and it is suitable for long-distance transmission. Disadvantages: The absolute position information of the axis rotation cannot be output.

Second, the absolute encoder

Directly output digital sensor, the sensor circular code disk has a number of concentric code channels in the radial direction, each track is composed of a transparent and opaque sector, and the number of sectors of adjacent code channels is doubled. The number of code channels on the code disc is the number of bits of its binary digit. The light source is on one side of the code disc, and the other side has a photosensitive element corresponding to each code channel; when the code disc is in different positions, each photosensitive element is based on The corresponding level signal is converted by illumination or light to form a binary number.

The feature of this type of encoder is that it does not require a counter, and a fixed digital code corresponding to the position can be read at any position of the rotary shaft. Obviously, the more code channels, the higher the resolution. For an encoder with N-bit binary resolution, the code wheel must have N code channels. At present, there are 16 absolute encoder products in China.