| 摘要 |
A photoelectric barrier grid comprises several juxtaposed light sources (5) each associated with a photoreceptor (6). A light source control (9) and a photoreceptor control (10) are provided to control the light sources and photoreceptors, to ensure emission and reception respectively of separate, consecutive light pulses. To permit synchronization with the light sources (5), the photoreceptors (6) can be controlled by the photoreceptor control (10) in function of the light pulses received. |
