encoderIt is a device that converts angular displacement or linear displacement into electrical signals. The former becomes a code wheel, while the latter is called a code ruler. According to the reading method, encoders can be divided into two types: contact type and non-contact type. Contact type uses electric brush output, where one electric brush contacts the conductive or insulating area to indicate whether the code state is "1" or "0"; The non-contact receiving sensitive element is a photosensitive element or a magnetic sensitive element. When using a photosensitive element, the state of the code is represented by a transparent area and a non transparent area to indicate whether it is "1" or "0".

According to the working principle, encoders can be divided into two categories: incremental and linear. An incremental encoder converts displacement into a periodic electrical signal, which is then converted into count pulses to represent the magnitude of displacement in terms of the number of pulses. Each position of the encoder corresponds to a specific digital code, so its indication is only related to the starting and ending positions of the measurement, and not to the intermediate process of the measurement.

Incremental rotary encoderBy converting the timing and phase relationship of its angle encoder through two internal photosensitive receivers, the increase (positive direction) or decrease (negative direction) of its angle encoder displacement can be obtained. After integrating digital circuits, especially microcontrollers, incremental rotary encoders have the advantages of being cheaper and simpler in angle measurement and angular velocity measurement compared to conventional rotary encoders.

Incremental encoderWhen the shaft rotates, there is a corresponding pulse output, and the counting starting point can be set arbitrarily, which can achieve infinite accumulation and measurement of multiple turns. One revolution of the encoder shaft will output a fixed number of pulses, which are determined by the number of lines in the encoder grating.

Type encoderThere is a Daima output corresponding to the position, usually in binary code or BCD code. The change in the size of the code can be used to determine the direction and position of the displacement, and the zero position code can also be used for power outage location memory.

optical encoder, is a sensor that converts mechanical geometric displacement on the output shaft into pulses or digital quantities through photoelectric conversion. This is a widely used sensor currently.

*The Nanjing Astronomical Instrument Development Center was founded in 1958 and is the largest research and development base in China, mainly focusing on the development of large and medium-sized astronomical instruments, while also taking into account other integrated instruments of optoelectronics, electromechanics, and computer technology. In December 2001, the company was transformed into a technology enterprise (limited liability company) directly under *, with research and design advantages in comprehensive disciplines such as instrumentation, optics, precision machinery, automatic control, and computer technology; It is the awarding point for doctoral and master's degrees in disciplines such as astrophysics, astronomical technology and methods; There are rare large and medium-sized optical cold processing equipment (optical workshop), precision mechanical processing equipment, and detection devices in China; It holds a domestic position in optical processing techniques such as birefringent crystals, non spherical surfaces, especially off-axis non spherical surfaces, and millimeter wave panel technology for radio telescopes.