| 摘要 |
PURPOSE:To detect humidity without error all the time, by judging a fault based on the result of comparison from a comparing part, which finds the difference degree between the heating cleaning characteristic of a humidity detecting element and an initial value. CONSTITUTION:A detecting part 1 is heated by a cleaning heater for a time period specified by a timer part 2. The maximum resistance value and the minimum resistance value, which are shown by the detecting part 1 for a specified time after the heating, are held by a peak holding part 3 and a low-value holding part 4. These held values are added to an operating part 5 and the difference is computed. Said difference is compared with the difference between the maximum value and the minimum value, which are to be generated if the detecting part 1 and the cleaning part do not fail, by a comparing part 6. Based on the signal sent from the comparing part, fault is judged by a fault judging part 7. Warning is issued by a fault warning part 8 based on the signal from the part 7, and the fault in the detecting part 1 can be reported. |
