| 摘要 |
PURPOSE:To improve control reliability by reading the control output state of a controlled unit again, by making a check on whether its contents are in an expected output state or not, and by sending an output ready signal when normal. CONSTITUTION:The contents of memory 2 stored with a program needed for control are decoded by CPU1 and then executed. Input signal 4 is processed by CPU1 after passing through digital input circuit 5 and input control circuit 6 and then supplied to output control circuit 7 and digital output circuit 8 in sequence to output signal 9. Signal 9 is fed back to re-read circuit 10 and then read into CPU1. Then, the read contents are collated with output contents in CPU1 and when the both agree each other, circuit 8 sends out output ready signal 11 and signal 11 and output signal 9 AND-ed by AND circuit 12 to generate control output 13. Since an output is sent out on reconfirming the output from circuit 8, error control is eliminated and reliability improves. |
