| 摘要 |
The optical barrier 1 detects objects in motion and in particular identifies vehicles moving along a track, and it comprises a transmission unit 4 placed at one side of the track and having a plurality of diodes 5 emitting infrared light, multiplexed and modulated at a predetermined frequency; a reception unit 6 placed at an opposite side of the track and having a plurality of infrared photoreceivers 7; and an electronic device 8 for managing the electric signals generated by the photoreceivers 7. The apparatus 8 comprises means 31, 32 of evaluating the degraded functionality of the transmission unit 4, and two signal units 33, 16 to indicate the functionality of the transmission unit 4 and of the barrier, activated by the evaluation means 31, 32. <IMAGE> |
