In the field of automation, the rotary encoder is used to detect the angle, speed, length, displacement and acceleration sensors.

Rotary shaft encoder rely, gear, ropes or measuring wheel control, linear movement can be detected. The rotary encoder also converts the mechanical parameters of the actual value to electrical signals, these electrical signals can be counter, tachometer, PLC and industrial PC processing.

The rotary encoder conversion receiving pipe the angle of the code wheel and the phase relationship between the timing by two internal photosensitive give its angular displacement of the code plate angle increases (positive direction) or decreased (negative direction).

Especially after joining the digital circuit is a single chip, incremental rotary encoder measures the angle and angular velocity measurements comparing absolute rotary encoder is more cheap and easy advantage.

The method according to the scale and form of the output signal, the rotary encoder can be divided into incremental, absolute and mixed three.

Incremental encoder features:

Incremental encoder is the direct use of the photoelectric conversion principle square wave pulse output three groups A, B and Z phase; A, B pulse phase difference of 90 groups, which can easily determine the direction of rotation, and a Z-phase per revolution pulse for homing. The advantage is that the principle of simple structure, mechanical average life of more than tens of thousands of hours, anti-interference ability, high reliability, suitable for long distance transmission. The disadvantage is that the absolute position information can not be output shaft rotation.

When the incremental encoder shaft rotation, there is a corresponding pulse output, the start of counting in any setting, multi-ring unlimited accumulation and measurement. Encoder shaft revolution will output a fixed pulse number of pulses is determined by the number of line encoder grating. When the need to increase the resolution, you can use 90 degrees out of phase A, B two-way signal multiplier or replacement of the high-resolution encoder.

Absolute encoder features:
Absolute encoders have the position corresponding to the generation of Mary output, typically binary or BCD code. From the change of code size can distinguish positive and negative directions and the location of displacement, absolute zero-bit code can also be used to power position memory. Absolute encoders conventional measuring range of 0-360 degrees.