JPS6446195A - Automatic fire alarm system - Google Patents

Abstract

PURPOSE:To eliminate the restriction of the number of the bits of fire data due to the return of classification data by providing a classification output part at a sensor and a classification detecting part at a receiver respectively and returning the classification data to the receiver as fire data at the time of the leading edge of a power source. CONSTITUTION:In an ordinary condition, an analog fire signal amplified by an amplifier 11 is inputted in an A/D converting part 12, and A/D converted fire data FD are returned in a prescribed returning sequence to a receiver 2. Next, after a supply voltage impressed to a signal line 3 is turned off for a constant period T1, when the voltage is turned on again, the leading edge is detected by a line voltage detecting part 14, the identifying signal of a level Vm in accordance with the classification of a sensor 1 is inputted from a constant voltage generating part 16 to the converting part 12 for a constant period T2 at the time of the return. Consequently, when polling is executed for the period T2, the A/D converted classification data are returned as data DC. At the receiver 2, a classification detecting device 21 detects and registers the data FD. At a signal processing part 22, the decision of the succeeding data FD is executed based on the registered data and a fire alarm at the time of the occurrence of the fire is executed.