Proximity switch with continuously operable test circuit responsive to bipolar double pulses

摘要

PCT No. PCT/EP84/00231 Sec. 371 Date Mar. 27, 1985 Sec. 102(e) Date Mar. 27, 1985 PCT Filed Jul. 26, 1984 PCT Pub. No. WO85/00712 PCT Pub. Date Feb. 14, 1985.The invention relates to a self-testing proximity switch, wherein the testing is carried out with the aid of bipolar double pulses which, independently of the switching state of the trigger stage, each time cause a short-timed triggering thereof. At the output of the trigger stage, the superimposed pulses can be evaluated by the test circuit in order to monitor proper functioning of the proximity switch.