DEVICE FOR MONITORING EXPLOSION-PROOF AREA ABNORMALITY

摘要

PURPOSE:To provide an explosion-proof area abnormality monitoring device where every system is the input system by light with perfect explosion-proof structure. CONSTITUTION:An input side optical fiber 4 is connected to the laser light source equipment 11 of an input monitoring device 6 and an output side optical fiber 5 is to a light receiver 12. A photosensors 1, 2 and 3 are branch-connected to both fibers 4 and 5 so as to be arranged in an explosion-proof area. A light pulse is emitted from the input monitoring device arranged in a non-explosion- proof area. The input monitoring device 6 executes synchronization with pulse light irradiation so as to control a gate in accordance with the pulse light responce time of the respective optical switches 1, 2 and 3 and the ON/OFF state of the respective optical switches area judged from received pulse light strength.