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About Rotary Encoder！
Changchun Rongde Optics Co.,Ltd. Release time：2016/3/7 Browse：810Introduction
The rotary encoder is used as the angular position sensor electromechanical switches. Its output is a digital coding usually a relative or absolute position, there are some, though rotary encoder sinusoidal output. Typically, rotary encoders plus a microprocessor and can be found in industrial applications (motor control) and a variety of human-computer input devices (computer mouse).
Type rotary encoder
Rotary encoders There are two main forms: absolute or incremental.
Absolute rotary encoder
Absolute rotary encoder to determine the absolute angular position. Each position encoder is unique, so if coupled position microcontroller failure will not be lost. In addition, each complete cycle of multi-turn absolute rotary encoder counts as opposed to a single rotation. Any type of absolute rotary encoder resolution is determined by the number of output bits may be. For example, an 8-bit single-turn absolute rotary encoder per revolution 256 unique location. In order to avoid race conditions interface digital logic output is typically implemented over gray encoding. Compared to rotary incremental encoders, absolute encoders are more expensive rotation, and the need to communicate with the microcontroller greater bandwidth. However, absolute rotary encoders combined system does not need to be re-initialized position loss due to power failure.
Incremental rotary encoder
Incremental rotary encoders (also called a relative rotary encoder) is used to measure the change in angular position. Bandwidth requirements are much lower. When using an absolute rotary encoders, only because they determine the direction and angle variation compared. Completion of this step, the two digital outputs in quadrature. To determine the direction of rotation, the relative phase between the quadrature output needs to be determined. A special way to do this is to check the value of each edge of the second quadrature outputs appearing first quadrature outputs. If the first signal is a high edge is detected, then we know that the first signal is leading by a quarter period. Taiwan, overseas Chinese, in the opposite direction of movement is detected when the second output rising edge is detected, the first signal is low.
Relative rotation of the encoder often have additional output, inverted: as quadrature output and a command and press the (logical XOR quadrature output signals).
Other Changes
, Optical, magnetic, or mechanically generated output waveform.
Mechanical coding from the past a pair of contacts of the rotating disk etched. Optical encoder is more powerful than mechanical, the use of replacement LED and a phototransistor contacts. By eliminating the need for mechanical contact with the disk of etching, higher resolution can be achieved with the optically encoded. Finally, the elimination of the magnetic encoding axis and located inside the sensor needs, therefore, they are not easy to wear and tear or bearing seals. Instead, the magnet (s) attached to the shaft and rotate directly past the magnetic sensor (s). Typically, this sensor relies on the Hall effect or variable reluctance either.
The rotary encoder can be equipped with a positioning location. These are usually found in the man-machine interface, digital mixer such as dial-up.
Product Specifications
Rotary encoder, the maximum speed, pulses per revolution by their environmental sealing, axial and radial forces ratings and output logic types (CMOS, TTL, etc.) distinction. See typical rotary encoder device specifications section below.
Yield
Absolute encoder, the output is an n-bit Gray code. The relative encoder, is required at least a pair of quadrature output. And a rotary encoder microcontroller is negligible, usually require a voltage divider and / or a maximum buffer circuit. When using a high-resolution rotary encoders, it is important to ensure that the buffer circuit and the microcontroller interrupt input can be solved by the fastest speed required for the application of the pulse.
The rotary encoder is used as the angular position sensor electromechanical switches. Its output is a digital coding usually a relative or absolute position, there are some, though rotary encoder sinusoidal output. Typically, rotary encoders plus a microprocessor and can be found in industrial applications (motor control) and a variety of human-computer input devices (computer mouse).
Type rotary encoder
Rotary encoders There are two main forms: absolute or incremental.
Absolute rotary encoder
Absolute rotary encoder to determine the absolute angular position. Each position encoder is unique, so if coupled position microcontroller failure will not be lost. In addition, each complete cycle of multi-turn absolute rotary encoder counts as opposed to a single rotation. Any type of absolute rotary encoder resolution is determined by the number of output bits may be. For example, an 8-bit single-turn absolute rotary encoder per revolution 256 unique location. In order to avoid race conditions interface digital logic output is typically implemented over gray encoding. Compared to rotary incremental encoders, absolute encoders are more expensive rotation, and the need to communicate with the microcontroller greater bandwidth. However, absolute rotary encoders combined system does not need to be re-initialized position loss due to power failure.
Incremental rotary encoder
Incremental rotary encoders (also called a relative rotary encoder) is used to measure the change in angular position. Bandwidth requirements are much lower. When using an absolute rotary encoders, only because they determine the direction and angle variation compared. Completion of this step, the two digital outputs in quadrature. To determine the direction of rotation, the relative phase between the quadrature output needs to be determined. A special way to do this is to check the value of each edge of the second quadrature outputs appearing first quadrature outputs. If the first signal is a high edge is detected, then we know that the first signal is leading by a quarter period. Taiwan, overseas Chinese, in the opposite direction of movement is detected when the second output rising edge is detected, the first signal is low.
Relative rotation of the encoder often have additional output, inverted: as quadrature output and a command and press the (logical XOR quadrature output signals).
Other Changes
, Optical, magnetic, or mechanically generated output waveform.
Mechanical coding from the past a pair of contacts of the rotating disk etched. Optical encoder is more powerful than mechanical, the use of replacement LED and a phototransistor contacts. By eliminating the need for mechanical contact with the disk of etching, higher resolution can be achieved with the optically encoded. Finally, the elimination of the magnetic encoding axis and located inside the sensor needs, therefore, they are not easy to wear and tear or bearing seals. Instead, the magnet (s) attached to the shaft and rotate directly past the magnetic sensor (s). Typically, this sensor relies on the Hall effect or variable reluctance either.
The rotary encoder can be equipped with a positioning location. These are usually found in the man-machine interface, digital mixer such as dial-up.
Product Specifications
Rotary encoder, the maximum speed, pulses per revolution by their environmental sealing, axial and radial forces ratings and output logic types (CMOS, TTL, etc.) distinction. See typical rotary encoder device specifications section below.
Yield
Absolute encoder, the output is an n-bit Gray code. The relative encoder, is required at least a pair of quadrature output. And a rotary encoder microcontroller is negligible, usually require a voltage divider and / or a maximum buffer circuit. When using a high-resolution rotary encoders, it is important to ensure that the buffer circuit and the microcontroller interrupt input can be solved by the fastest speed required for the application of the pulse.
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