The working principle of magnetic encoders！

The purpose of magnetic drum magnetization is to make a small magnetic pole on the drum is magnetized, so that when the drum with the motor rotation, the drum can produce periodic magnetic flux leakage, the role of the magnetic resistance on to achieve coding . The number of magnetic poles determines the resolution of the encoder, drum magnetic pole uniformity and remanent magnetic strength is to determine the encoder structure and output signal quality important parameters. The following figure: magnetic encoders drum surface distribution

Magnetoresistive sensor is made of magnetoresistive sensor, magnetoresistive devices can be divided into semiconductor magnetoresistive devices and ferromagnetic devices. In order to improve the sensitivity of signal sampling, taking into account the compensation effect of the differential structure on the temperature characteristics of the sensitive components, two stripes with a phase difference of 2/2 are usually etched to form a half-bridge series network. As shown below

Magnetoresistive sensor is made of magnetoresistive sensor, magnetoresistive devices can be divided into semiconductor magnetoresistive devices and ferromagnetic devices. In order to improve the sensitivity of signal sampling, taking into account the compensation effect of the differential structure on the temperature characteristics of the sensitive components, two stripes with a phase difference of 2/2 are usually etched to form a half-bridge series network. As shown below:
     At the same time, in order to improve the resolution of the encoder, a plurality of magnetoresistive sensitive elements can be arranged side by side on the magnetic head, and the magnetoresistive element rotates the drum to output the corresponding sine wave in the case of applying voltage. The principle can be explained simply: NS drum magnetic drum for circular motion, magnetoresistive sensor made with the magnetic field changes in the resistance also changes, and sensing SinA, SinB two voltage waveforms. Magnetoresistive sensor structure as shown in Figure, divided into two groups by the 8 magnetic spacing of 1/4 NS spacing. In Mr1, Mr2 and Mr3, Mr4 can be detected at the junction of Sin voltage waveform, the same principle in Mr1 ', Mr2' and Mr3 ', Mr4' can be detected at the junction of SinB voltage waveform

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