| 摘要 |
<p>PURPOSE:To turn a control signal OFF quickly upon retreat of a person from a detection area while preventing erroneous function by turning the control signal ON when detection signals of the person, entering into or retreating from the detection area, are outputted a plurality of times within a predetermined time while furthermore setting the OFF delay time of the control signal. CONSTITUTION:An infrared detector outputs positive and negative detection signals, respectively, when a human body enters into and retreats from the coverage of detecting beam. When the detection signals exceeds a positive or negative threshold level, a control signal is turned ON and OFF delay time thereof is updated to be lengthened or shortened. If the OFF delay time is not updated again within some time interval, an OFF signal is outputted. A single shot detection time is set longer by a predetermined time interval than each OFF delay time concurrently with updating of setting. During single shot detection time, control signal is turned ON for every output of detection signal and similar updating of setting is performed. In the initial state, control signal is turned ON for the first time when detection signals are outputted a plurality of times within a predetermined time interval and updating of setting is performed similarly.</p> |
