Magnetic sensing allows for large gaps between sensor and material measure (usually magnetic ring or center magnet). This way they can be positioned separately from each other, eliminating the need for precision ball bearings usually deployed with rotary encoders.
In parallel, this allows for high mounting tolerances. This provides more flexibility in design and installation. As there is no need for bearings, there is no conventional wear either. This makes the encoders immune to dust, dirt or textile fibers, immune to shaft currents or bearing loads, and robust against vibration and shock.
Technical Report – EB200E