| 摘要 |
PURPOSE: To accurately display the position number of a lamp, in which a fault is generated, by providing each lamp with a detecting element, and utilizing a lamp feeder line connected in series so as to transmit and receive a signal. CONSTITUTION: Each detecting element is connected in parallel with a lamp by cramps MA, MB, and feeds out the signal from a crystal oscillator 56 to a feeder line through a transmitter 54 and a power source circuit 60 with a timing set by counters 48-51. When a lamp is failed, an over-voltage detecting element 61 detects the generation of fault, and stops an oscillator 56 through an AND circuit 55, and while generate a short-circuit in cramps MA, MB through an electrifying voltage restraint unit 62 and an electrifying voltage restraint bypass circuit 63. In a control device, a pick-up is connected to one of the feeder lines without generating a contact, and the feeder waveform of the lamp and an envelope of the response signal is read out. When the lamp is failed, since the generation of response signal is stopped, position number of the failed lamp such as the lighting of air port can be accurately detected for display by counters synchronized with the detecting element. |
