| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a smoke sensor which can improve accuracy of smoke detection and can perform stable smoke detection. <P>SOLUTION: According to a smoke sensor, initial values of output signals from first and second amplifiers 5 and 6 are stored as first and second initial values in a storage unit 16B. The initial values are stored in the storage unit 16B on a stage of e.g., shipping from a factory. A value V2(0)/V2(k) is obtained by dividing a second initial value V2(0) with a value V2(k) of the output signal from the second amplifier 6 measured at a certain time after installation. By multiplying a value V1(k) of the output signal from the first amplifier 5 measured at that time with the value V2(0)/V2(k), influences exerted upon the value V1(k) of the output signal by variation caused by the ambient temperature during the measurement or aging of a light-emitting element are corrected and reduced. When a determination value obtained by subtracting the first initial value V1(0) from a value V1(k)×V2(0)/V2(k) of the output signal after the correction exceeds a detection threshold value, a signal processing circuit 16A then outputs a smoke detection signal. <P>COPYRIGHT: (C)2012,JPO&INPIT |
