Knowledge function of rotary encoder

Common types of rotary encoders include incremental encoders, absolute value encoders, photoelectric encoders, magnetic encoders, capacitive encoders.What is the difference between these types of encoders?

1. Incremental encoder

When the incremental encoder shaft rotates, there is a corresponding phase output. The determination of the direction of rotation the increase decrease of the number of pulses need to be realized with the help of the direction circuit counter at the rear. The counting starting point can be set arbitrarily, it can realize unlimited accumulation measurement of multiple turns. It is also possible to use the Z signal of each pulse transmitted as a reference mechanical zero position. When the pulse is fixed the resolution needs to be improved, two signals with a 90 degree phase difference A B can be used to multiply the original pulse number.

2. Absolute value encoder

In the case of absolute encoder shaft rotator, there is a code (binary, BCD code, etc.) output corresponding to the position, the positive negative direction the position of the displacement can be determined the change of the code size, without the need for a direction determination circuit. It has an absolute zero code. When the power is cut off turned off then turned on re-measured, the code of the power cut shut down position can still be read accurately, the zero code can be found accurately. -Under normal circumstances, the measuring range of absolute encoder is 0 to 360 degrees, but special models can also achieve multi-turn measurement.

3. Optical electric encoder

The photoelectric encoder is a sensor that converts the mechanical geometric displacement on the output shaft into pulses digital quantities through photoelectric conversion. It is a sensor with many applications at present. The general photoelectric encoder is mainly composed of a grating disc a photoelectric detection device. The grating disc is a circular plate with a certain diameter. A number of rectangular holes are equally opened on the upper part. Because the photoelectric code disc is coaxial with the motor, when the motor rotates, the grating disc the motor rotate at the same speed. The detection device composed of electronic components detects the output Several pulse signals. The current motor speed can be reflected by calculating the number of output pulses of the photoelectric encoder per second. In addition, in order to determine the direction of rotation, the code wheel can also provide two-channel optical code output with a phase difference of 90°, determine the rotation of the motor according to the state change of the dual-channel optical code.

Photoelectric encoders generally have relatively high detection accuracy, but require higher protection requirements when used outdoors in harsh environments, are suitable for use in condensation environments.

4. Magnetic encoder

The main part of the magnetic encoder is composed of a magnetoresistive sensor, a magnetic drum, a signal processing circuit. The magnetic drum is recorded into small magnets at equal intervals. After the magnets are magnetized, they generate periodic spatial leakage magnetic fields when rotating. The magnetic sensor probe converts the changing magnetic field signal into the change of the resistance value through the magnetoresistance effect. Under the action of the applied electric potential, the changed resistance value is converted into the change of the voltage, which is processed by the subsequent signal processing circuit to simulate the voltage signal. It is converted into a digital signal that can be recognized by the computer to realize the encoding function of the magnetic rotary encoder. The purpose of magnetic drum magnetization is to magnetize each of the small magnets on the drum, so that when the drum rotates with the motor, the drum can produce cyclically varying spatial magnetic flux leakage act on the magnetic resistance. Realize the coding function. Compared with the optical detection principle, the magnetoelectric detection principle has the characteristics of anti-vibration anti-pollution, which can be applied to the traditional photoelectric encoder.

DEUPREE (Qingdao) Industrial Technology Co., Ltd. is an integrated enterprise focusing on the research development of automated industrial technology equipment manufacturing. The company’s products mainly include rotary motion sensors, linear displacement sensors, object recognition sensors, laser rangefinders, process control measurement Class instruments, signal detection systems, signal transmission systems, immature drive systems, UPS safety power supply systems, automation equipment energy-saving cleaning auxiliary equipment systems are limited to this, we can also customize flexibly customize according to customer needs to meet different Different needs of customers.