Precise and robust hall effect gap sensor with common electrical and magnetic noise reduction technique

Precise Hall effect gap sensor with differential and shielding structure for effective reduction of common electrical and magnetic noise is reported. Applied to a transport system with magnetic levitation, resolution of the sensor resulted in 2 μm while with 2 mV/μm sensitivity at main sensing range of 1.5mm. Less than 1 μm variation is observed despite the ambient magnetic field. Levitation error of the transport system with the gap sensor satisfied a given specification of less than 10 μm.