| 摘要 |
PURPOSE:To enable proper fail-safe by putting the fall-safe of outdoor illumination in proper fail-safe conditions in accordance with daytime and nighttime based on the light receiving signals of a photosensor and the signals of a failsafe detection part. CONSTITUTION:Even if it becomes the condition of fail-safe and a fail-safe detection part 13 detects it, in the place where there is bright day light, the outdoor illumination is put out by a gate circuit G1 which received the light receiving signal of a photosensor 10 that sensed day light. If it is dark when the fail-safe detection part 13 detected the fail-safe condition, the signal level of the photosensor 10 becomes reverse, and outdoor illumination is lighted by the output of a gate circuit G2. Also, if it is in the case of normal condition without becoming fail-safe, the transmission level at this time becomes H level, and the fail-safe detection part 13 detects it, and lighting control at normal time is done. Hereby, proper failsafe can be done. |
