Magnetic encoder

The core technology of the encoder is the way it provides position information. Hengshiro provides two position signal detection technologies: optical principle (using mask and phase array technology) and magnetic principle. The main difference between the two encoders is the way the position signal is collected. Understanding how the two encoders work helps us decide which type of encoder to use.

Magnetic encoders are often referred to as magnetoelectric encoders. They are a new type of angle or displacement measuring device. Its principle is to use magnetoresistance or Hall elements to measure the angle or displacement of changing magnetic materials. The change of the angle or displacement of the magnetic material will cause a certain resistance or voltage change. The change is amplified by the amplifying circuit, and the pulse signal or analog signal is output after processing by the single-chip microcomputer to achieve the purpose of measurement. The structure of the magnetic encoder is divided into two parts: sampling detection and amplifying output. The detection is generally completed by a bridge circuit. There are two types of half bridge and full bridge. The amplifying output is generally realized by devices such as transistors and operational amplifiers.

Magnetic encoder technology

The photoelectric encoder uses light to identify the current position. The principle of a magnetic encoder is similar, except that a magnetic field signal is used. A magnetic turntable and magnetoresistive sensor are used inside the magnetic encoder. The rotation of the magnetic turntable will cause a change in the internal magnetic field strength. The magnetoresistive sensor detects the change in the magnetic field strength and then processes the signal to output the signal. The number of magnetic poles of the magnetic turntable, the number of magnetoresistive sensors and the way of signal processing determine the resolution of the magnetic encoder. The advantage of using the magnetic field principle to generate signals is that the magnetic field signals will not be affected by dust, humidity, high temperature and vibration.

Application of magnetic encoder

Compared with traditional photoelectric and grating encoders, magnetic encoders have the characteristics of anti-vibration, anti-corrosion, anti-pollution, anti-interference and wide temperature, and can be used in fields where traditional photoelectric encoders cannot adapt. Magnetic encoders are encoders specially designed for extremely harsh environments. These occasions generally require wide temperature characteristics, can withstand strong vibrations and shocks, and have a high degree of protection.

In addition, we also have a reliable signal output circuit, simple installation method, can greatly reduce the loss of downtime. Usually used in metallurgy, papermaking and woodworking machinery. High-performance magnetic encoders can be widely used in industrial control, machinery manufacturing, shipbuilding, textiles, printing, aviation, aerospace, radar, communications, military and other fields.

The difference between magnetic encoder and photoelectric encoder

Traditional photoelectric encoder code discs are made of glass, metal, and plastic. The glass code disc is a thin engraved line deposited on the glass. Its thermal stability and accuracy can meet common standards and requirements, but it is easy to break. The metal code disc is directly engraved with pass and not pass, and it is not fragile, but because metal has a certain width requirement, the accuracy is limited, and its thermal stability is one order of magnitude worse than that of the glass code disc. Plastic code discs are economical, their cost is low, accuracy and high temperature resistance cannot meet high requirements. The magnetic encoder adopts a magnetoelectric design, which generates and provides the absolute position of the rotor through magnetic induction devices and the change of the magnetic field. The magnetic device replaces the traditional code disc, which makes up for these defects of the photoelectric encoder and is more shock-resistant. , Corrosion resistance, pollution resistance, more reliable performance, simpler structure. The photoelectric incremental encoder calculates the accuracy by marking lines on the code disc, so the higher the accuracy, the larger the code disc, the larger the encoder volume, and the accuracy is not continuous. Magnetic encoders do not have such restrictions and can be very small.