Incremental encoder internal structure material2021

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. The incremental encoder rotates a circle to send out a pulse signal, and the user is equipped with a corresponding device to calculate the distance, displacement, speed, and angle according to the pulse data.

Encoder is a device that converts angular displacement or linear displacement into electrical signals. The former is called a code wheel, and the latter is called a yardstick. Encoders can be divided into contact type and non-contact type according to the reading 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".

The incremental encoder consists of a photoelectric code disc with a shaft in the center, on which there are circular and dark engraved lines, and is read by photoelectric transmitting and receiving devices to obtain four groups of sine wave signals combined into A, B, C, D , Each sine wave has a phase difference of 90 degrees (relative to a cycle of 360 degrees), 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 per revolution To represent the zero reference position. Since the phases A and B are 90 degrees apart, the positive and negative rotations of the encoder can be judged by comparing whether the A phase is the first or the B phase. The zero reference position of the encoder can be obtained through the zero pulse.

The materials of the rotary encoder code discs on the market include glass, metal, and plastic. The glass code disc is made of thin engraved lines deposited on the glass, which has good thermal stability and high precision. The metal code disc is directly engraved with and without pass. , Not fragile, but because the metal has a certain thickness, the accuracy is limited, and its thermal stability is an order of magnitude worse than that of glass. The plastic code disc is economical, and its cost is low, but the accuracy, thermal stability, and life Both are worse.

The resolution of the rotary encoder is called the resolution by the number of open or dark engraved lines provided per 360 degrees of rotation, also known as the resolution index, or directly called the number of lines, generally in the range of 5 to 10,000 lines per revolution.