| 摘要 |
PURPOSE:To shorten the switching time of a system at the time of a fault and to perform the switching of the system, continuing a processing. CONSTITUTION:When there is no response to the output signal outputted by an A central processing part 2 within a preliminarily fixed period, a B central processing part 3 outputs the same signal as the A central processing part 2. Further, when there is no response, an information transmission control part 5 judges as the fault on the side of a station to be monitored, stops the transmission of control information to a station to be monitored 11 which does not response and moves the A central processing part 2 or the B central processing part to the polling of the next station to be monitored 11. When there is a right response to the signal of the B central processing part 3 when there is not a response to the signal outputted by the A central processing part 2, it is judged that a fault exist in the A central processing part 2, the information transmission control part 5 does not transmit a control signal to the A central processing part 2, the A central processing part is detached from a system and an operation is continued by the B central processing part 3. |
