| 摘要 |
PURPOSE:To properly execute a system switching operation by providing a system switching control means to switch a control system based on a first instruction from a first or second controller in a standby. CONSTITUTION:A high order device 1 issues a second instruction to a second or first controller 4 or 2 in the standby by the chance of the reception of error generation information from the first or second controller 2 or 4 in the middle of operation or an instruction from an external part. The first or second controller 2 or 4 issues a first instruction to a system switching control means 3 by the chance of the second instruction, and it starts the system switching operation. Thus, the execution of the system switching operation to be mistaken due to the malfunction of the first or second controller 2 or 4 can be surely prevented. |
