| 摘要 |
PURPOSE:To attain smooth supervisory control for a terminal device without causing large rise in cost and to detect instantly its change in state, by supervising cyclicly plural terminal devices at all times. CONSTITUTION:A central device 1 is connected to the plural terminal devices R1-Rn via a single transmission line, and the device 1 is provided with a transmission/receiving circuit 11 transmitting a supervisory and control signal to the terminal devices R1-Rn and receiving a supervisory return signal from the terminal devices R1-Rn to the supervisory and control signal. Further, the device 1 is provided with a sequential supervisory control circuit 21, which controls the transmission and receiving circuit 11 to read out sequentially the terminal devices R1-Rn so as to supervise and control cyclicly and continuously the terminal devices R1-Rn. Then, the constitution of the supervisory controller is simplified, the terminal devices R1-Rn are supervised and controlled smoothly and the change in state is detected instantly. |
