The working principle of photoelectric encoder！

1) optical encoder consists of: a central shaft of the optical encoder on the disc is regularly engraved with translucent and opaque lines on both sides of the disk, the light emitting element and a photosensitive member placed. When the disk rotates, the photosensitive member varies in synchronism with the received light quantity of light-transmitting lines of the photosensitive member after shaping the output waveform into a pulse, a sine wave signal to obtain four combinations: A, / A, B, / B, each sinusoidal wave by 90 degrees out of phase (with respect to a cycle of 360 degrees) used to determine the direction of rotation. There Phase Z flag (refer to mechanical zero) on the code disc, each revolution of a Z-phase pulse output to represent the zero reference position.
2) Since the A, B two-phase difference of 90 degrees, by comparison with the previous A or B the first phase, in order to determine the encoder forward and reverse, if the A-phase pulse than the B-phase pulse ahead of the photoelectric encoder forward, otherwise reverse; the zero pulse can be obtained encoder zero reference position.
3) When the number of pulses has been fixed and the need to improve the resolution, you can use 90 ° phase A, B two signals, the original pulse count is 2-fold or 4-fold.
Each ring 4) rotation of the shaft, incremental encoders provide a certain number of pulses. Measured periodically or the pulses per unit time can be used to measure the speed of movement. If it is accumulated in a reference point behind the number of pulses, the calculated value represents the angle of rotation or stroke parameters. 90º phase difference between two-channel encoder output pulses. Rotation sensing signal to make the received pulse of the electronic device receiving the shaft, and therefore can be used to achieve bi-directional positioning control; In addition, the three-channel incremental rotary encoder pulse per revolution is called a zero signal.

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