Adjustable proximity switch using magnetic field sensor

摘要

The proximity switch has a magnetic field sensor arranged in the neutral zone of a two-pole permanent magnet, responding to a release element being brought close to the latter to detect a magnetic induction variation. The variation is evaluated to alter the switch state.The permanent magnet comprises two immediately adjacent partial permanent magnets (M1, M2) with different coercivity field strengths. The magnet with the lower coercivity field strength is partially demagnetised to shift the neutral zone.