| 摘要 |
PURPOSE:To switch systems smoothly, by inputting output data of a control system to a standby system and comparing its calculated result with that of the standby system to check whether the standby system is satisfiable or not. CONSTITUTION:Not only input/output are performed between a CPU 10A of the control system and an input/output device 20A, but also an input image of a process 6 is inputted to a CPU 10B of the holding system also from the CPU 10A of the control system through a computer connecting device 3 and is subjected to the arithmetic processing, and output data of the CPU 10A of the control system is inputted to the standby system through an output changeover switch 9. The calculated result is compared with output data; and if the difference between them is larger than a set allowable deviation, the standby system is judged to be abnormal and an alarm is generated. |
