| 摘要 |
PROBLEM TO BE SOLVED: To easily and speedily confirm fault contents by providing at least one of a light reception part and a light transmission part with a trouble lamp and selectively displaying which kinds of abnormality has occurred according to how many times the trouble lamp blinks. SOLUTION: A fire decision is made by using fire sensitivity set previously in an internal memory by operating a monitor distance changeover switch 16 and from a calculated dimming rate and it is judged that a fire is taking place when the dimming rate is larger than prescribed fire sensitivity and not when less than the fire sensitivity. Then it is decided whether an update time as a reference value is elapsed to make an abnormality decision, and it is decided whether or not the reference value or photodetection quantity is abnormal. In the case of abnormality, an abnormality is outputted and whether or not the photodetection quantity is excessive is decided as the kind of the abnormality; when so, namely, the photodetection quantity exceeds the reference value (photodetection quantity saturation), the trouble lamp 19 is turned on and also turned on again a prescribed time later. Namely, the trouble lamp 19 is blinked four times in the case of the photodetection quantity saturation.
|
