China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Magnetic encoder is a sensor that measures rotational angle or position based on changes in magnetic fields. In automated moving bed positioning in nuclear magnetic resonance imaging equipment, there are mechanical gearbox-type absolute multi-turn encoders. For the azimuth, elevation, and magnetic pole position positioning of large communication transmission antennas, anti-interference encoders are also required. So why are they not affected by strong magnetic fields?
Magnetic encoders are able to resist interference from strong magnetic fields mainly due to their internal design and measurement methods. The following are the main reasons.
Structural diagram of Shaft End configured magnetic encoder, The advantage of the shaft-end configuration is that by combining radially magnetized magnets and Hall elements that detect transverse magnetic field strength, it is easy to achieve an encoder that is resistant to shaft eccentricity.
1. Magnetic encoders typically use transverse Hall elements, which are sensitive to magnetic fields perpendicular to the chip surface (orthogonal to the chip surface) but insensitive to magnetic fields in the horizontal plane. Therefore, external magnetic fields have little effect on them.
2. The magnetic encoder uses a differential measurement method, which means that it can only sense the difference in the magnetic field between the two sets of Hall sensors. Although an external DC magnetic field may affect the absolute value of the overall magnetic field, it does not affect the differential signal measured by the sensor. Thus, even if there is a strong external magnetic field, it will not cause the encoder to produce misreadings.
3. Hall sensors have low sensitivity, which makes them less responsive to external magnetic fields. Since the magnetic field of the magnet in the encoder's working environment is usually strong enough, and the magnetic field around the sensor is also strong enough to remain stable, it is not easily affected by external strong magnetic fields.
4. In particular, magnetic encoders that output absolute value signals are designed to be less susceptible to external magnetic fields. This allows this type of encoder to operate stably even in strong magnetic field environments.
In summary, magnetic encoders are ingeniously designed to effectively avoid interference from external strong magnetic fields, ensuring their reliability in complex environments. Currently, several magnetic encoders with excellent anti-interference capabilities, including resistance to strong magnetic fields, include the ROQ425 from German company HEIDENHAIN, the ATM60 from German company SICK, the GMX60 and GMX425 from GEMPLE Jingpu, and the CEM58 from German company TR.
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