| 摘要 |
PURPOSE:To reduce circuit scale to be backed-up when input power supply is interrupted at a remote supervisory device itself and to reduce the electrostatic capacity of a capacitor for backup or to prolong backup time. CONSTITUTION:A buffer 4 is provided between a supervisory and control circuit 8 in the remote supervisory device and a communication interface circuit 2, and a one-chip microcomputer 3 is connected between the buffer 4 and the communication interface circuit 2. Since the circuit range to execute power supply backup with the capacitor after the interruption of power supply is limited only to the communication interface circuit 2, buffer 4 and microcomputer 3 and the microcomputer 3 executes control after the power supply interruption, the current consumption of circuits to back-up power supply is reduced. |
