| 摘要 |
<p>PURPOSE:To eliminate difficulty and uncertainty in the decision of a threshold value to detect the fault of a sensor due to the steep change in a measuring signal by operating and setting a rate of change limiting value in the output of an input part from the response characteristic of a controller input part for sensor output, and setting it as a factor to judge the fault of the sensor. CONSTITUTION:A PV signal based on the measuring signal is fetched from the sensor to a controller control and arithmetic part 13 at every constant cycle, and a differential signal DELTAPV(a) with the PV signal of a preceding cycle and furthermore, a rate of change limiting value DLs found from the response characteristic of the controller input part 11 for sensor input are calculated, respectively. The rate of change limiting value is compared with the differential signal of the PV signal at every control cycle, and when the differential signal exceeds the rate of change limiting value, it is judged as the fault of the sensor due to the steep change of the PV signal, and thereby, the threshold value to detect the fault of the sensor is set uniformly and automatically.</p> |
