| 摘要 |
<p>PROBLEM TO BE SOLVED: To quickly detect the malfunction due to foreign matter, etc., by performing the diagnosis of the transmission/reception operation of a sensing part and to always sense a vehicle with stable sensitivity. SOLUTION: On a vehicle stopper provided on a parking lot, a sensing part 5 is provided. A transmission part 5b transmits an ultrasonic wave S1 and the presence of the vehicle is sensed by depending on whether the reflected ultrasonic wave S 2 reflected on a vehicle 10 is detected by a reception part 5c or not. At the time of a self-diagnosis, the leaked ultrasonic wave S3 when the ultrasonic wave S1 is transmitted, is fetched by a fetching means 5h. When the ultrasonic wave S2 is not detected, an operation diagnosis part 5j outputs an abnormal signal.</p> |
