| 摘要 |
<p>A fire sensor apparatus is provided with a fire sensor which has a built-in microcomputer and in which fire detection levels can be varied according to changes in environmental conditions (noise level) in the area in which it is installed. A signal from a sensor (1) is digitized in an A-D converter (3) and is input to a comparator (12). A CPU (5) determines the current time from a clock (4) and removes from a memory accumulated data on operating leveland noise level at the corresponding time in the past. The CPU (5) sets an operating level for the time concerned by executing a predetermined calculation, and compares this operating level with the signal from the sensor (1). An abnormal state is indicated at (14) or the accumulated data is renewed, according to the result of the comparison. Thus it is possible to set an appropriate operating level according to changes in noise level, and fire detection can be effected with a suitable detection sensitivity. </p> |
