Encoder working principle and function description

An encoder is a device that compiles and converts signals or data into a form that can be used for communication, transmission and storage. Encoder is a device that converts angular displacement or linear displacement into electrical signals, and is a logic circuit with encoding function. The encoder has several inputs, and only one input signal is converted into a binary code at a certain time. If an encoder has N input terminals and n output terminals, the relationship between the output terminal and the input terminal should satisfy the relationship N≤2n.

Below we briefly introduce the principles of several encoders.

2. Encoder principle-optical encoder

The optical encoder consists of a photoelectric code disc with a shaft in the center, on which there are circular and dark engraved lines. When the disc rotates by a pitch, the photosensitive element gets A and B signals with 90 degrees under the illumination of the light-emitting element. The phase difference sine wave, this group of signals is amplified and shaped by the amplifier, and the output square wave is obtained. When the phase A leads the phase B before the phase B, it is the positive direction rotation. The phase relationship between the phase A and the B phase can be used to distinguish the forward and reverse rotation of the encoder. A pulse C is generated at a fixed position when the shaft rotates once to obtain the encoder The zero reference position. After the AB phase pulse signal undergoes frequency-voltage conversion, a voltage signal proportional to the rotating shaft speed is obtained, and the speed value and displacement can be measured.

3. Encoder principle-magnetic encoder

The principle of the magnetic encoder is to form a pulse train by magnetic force to generate a signal. It is characterized by mixing rare earth magnetic powder in the unvulcanized rubber to form a magnetic rubber blank, which is vulcanized and adhered to the reinforcing ring to form a magnetic rubber ring. The ring alternates with magnetism in a circular shape, producing S poles and N poles. At the same time, a new SMR or Hall-effect sensor is used as the sensitive element, and the signal is stable and reliable.

4. Encoder principle-incremental encoder

　　 Incremental encoder outputs pulses when rotating, and the counting device determines its position. When the encoder does not move or the power is cut off, it relies on the internal memory of the counting device to remember the position. In this way, when the power is off, the encoder cannot move. When the power is on, the encoder cannot lose the pulse due to interference during the pulse output. Otherwise, the zero point of the counting device will shift, and this deviation There is no way to know the amount of shift, only after the wrong production results appear.