GATE OPENING/CLOSING SENSOR AND GATE OPENING/CLOSING MONITORING SYSTEM

PROBLEM TO BE SOLVED: To provide a technology which can accurately monitor the opening/closing state of a gate in a gate opening/closing sensor and a gate opening/closing monitoring system using an optical contact. SOLUTION: The gate opening/closing sensor comprises: an optical contact for controlling (on/off-operations of) light emitted to an optical fiber according to the strength of a magnetic field; a magnetic field generating part (for example, a magnet) for imparting a constant magnetic field to the optical contact; and a magnetic field shielding part for shielding the magnetic field which is imparted to the optical contact by the magnetic field generating portion according to the opening/closing state of a gate such as a water gate and a sluice gate. The optical contact and the magnetic field generating part are installed so as to keep a fixed separation distance (distance within a range influenced by the magnetic force) regardless of the opening/closing state of the gate. COPYRIGHT: (C)2011,JPO&INPIT