In optical encoders, environmental interference can have a significant impact on position sensing. Particles or fluids that make their way between the LED light source, disk, and photo sensors can easily interfere with the light source, which is critical to position sensing. One way around this is with environmental sealing, but this process adds cost to an already relatively expensive position sensing solution.
Contactless magnetic rotary encoders, on the other hand, are fully functioning even when such environmental contamination makes its way between the magnet and the sensor. The magnetic field can easily pass through these elements, allowing the sensors to determine absolute position even in relatively dirty environments. This also applies to applications that may experience wide temperature ranges resulting in condensation that could interfere with optical encoders.
In regard to temperature, contactless magnetic rotary encoders are typically designed for a range of -40° to +125°C, or higher in some cases. In comparison, optical encoders typically only operate up to 85°C without requiring an upgrade to a laser cut disk. While linear Hall sensors themselves are often rated to 150°C, this assumes that the magnet and sensor both meet this rating. Linear sensors typically do not have the same accuracy as either contactless magnetic rotary encoders or optical encoders.
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