| 摘要 |
PURPOSE:To accurately detect the failure of analog output circuit being the final output section in a short time, by providing the processing circuit which compares the signal converting analog output signal into digital amount with the original digital signal of the analog output signal. CONSTITUTION:An analog input circuit 3 fetches the analog input signal 2 detected at the sensor 1 and converts it into a digital signal 4. A central processor 5 fetches the digital signal 4 from the analog input circuit 3 and outputs the digital signal to the analog output circuit 7 after operation. A digital output circuit 10 fetches the signal 6 and gives an output 11 to the processing circuit 12. On the other hand, the selector 13 is switched with the switching signal 16, the analog output signal 8 is fetched to a digital converter 14d and outputted to the processing circuit 12 as a digital signal 15. The circuit 12 compares the signal 11 and 15 and makes decision of failure through the rate of change of the signal 15. |
