| 摘要 |
PURPOSE:To reduce the cost of the hardware and to realize a fail-safe system, by multiplexing a central arithmetic processing unit and having a software-like process for switch of a normal output. CONSTITUTION:A double structure is secured for a central arithmetic processing unit CPU. Both CPU-A system 5 and CPU-B system 6 perform the processes on the basis of the data given from analog input devices 3 and 4 and digital input devices 11 and 12 respectively. Each CPU always has a self-diagnosis. If a fault is detected through the self-diagnosis, the fault signal is set at ''1''. A logic circuit 90 performs a logic operation based on the fault signal and controls the digital input device. As a result, the normal CPU is selected at all times, and no output is produced when both systems A and B are faulty. |
