| 摘要 |
PURPOSE:To prevent the wrong actuation of the titled device due to instantaneous power failure from occurring by a method wherein commercial power source pulse information is superposed from an outdoor control device on multiplex transmission line independently of a microcomputer. CONSTITUTION:Pulsating current is obtained by rectifying commercial power source 13 stepped down by a transformer 14 by means of a diode bridge 15. Pulse (b), which indicate the zero-crossing point of commercial power source are issued from a transistor 19 by supplying said pulsating current through a resistor 16 to the gate of the transistor 19. The pulse (b) and the signal (c) outputted from the transmitting port 6a of a microcomputer 4a are ORed at an OR gate 20 in order to set the output signal of the OR gate 20 through a transmission circuit 5a to a multiplex transmission line 8. Accordingly, the pulse signals (b) indicating the zero-crossing point of commercial power source 13 is superposed on the multiplex transmission line 8 at all times. On the other hand, when each unit receives signals, the unit transmits signals in such a manner that the signals do not overlap with the pulses indicating the zero-crossing point of commercial power source. |
