| 摘要 |
PURPOSE:To check a terminal equipment wiring state by processing a voltage based on a current flowing to a current limiting resistance, by two comparing circuits to which a different prescribed reference voltage is supplied, and controlling a display and an alarm. CONSTITUTION:A limited current by which terminal equipments 31-3n whose impedance is remarkably smaller than an impedance of a terminating set 4 are not operated is supplied to a current limiting resistance Rx from a signal generating circuit 2 through a continuity test control part 1. A voltage generated across the resistance Rx by a supply of this current is amplified by an amplifying circuit 5, and applied to inversion and non-inversion terminals of comparing circuits 6a, 6b in which different prescribed reference voltages V1, V2 are applied to the inversion and non-inversion terminals, respectively. Also, when a wire l is short-circuited, and when it is disconnected, an output of the circuit 6a and an output of the circuit 6b are inverted to H, respectively, a display alarm circuit 8 is operated, a wiring state of the apparatuses 31-3n, 4 etc. for controlling a shutter, etc. through a relay contact r0 switched by a fire sensitive signal can be checked without operating the apparatuses 31-3n, 4, etc., and the reliability of an exhaust gas-proof controlling system is improved. |
