An inductive proximity sensor has a resonant circuit including a sensing coil and driven by an oscillator at a predetermined frequency. To sense selectively ferrous and non-ferrous objects, the excitation frequency is a subcritical excitation frequency and discriminator logic is provided to process a...http://www.google.fr/patents/US5519317?utm_source=gb-gplus-shareBrevet US5519317 - Inductive proximity sensor for detecting ferrous and non-ferrous objects
Inductive proximity sensor for detecting ferrous and non-ferrous objects
