| 摘要 |
PURPOSE:To prevent a wrong display due to the noise, by using the difference of time behaviors of an output signal to judge whether the noise exists or not. CONSTITUTION:The output of a sensor is amplified by the amplifires 5 and 6 and converted into a DC signal through an AC/DC converter 7 to be fed to the comparatorsIand II as well as to an integral network 8. The high threshold value A0 showing the open state of a valve is applied to the comparatorI; and the threshold value Aa showing the leakage of the valve is applied to the comparators II and III respectively. These comparators deliver the binary signals to a logical circuit 9 when their inputs exceed each threshold value. The integral network 8 has an integral time constant whose output has virtually no change to the noise and rises up with a slight time delay when the leakage occurs and the valve is opened. The circuit 9 displays the normal state, the occurrence of leakage and the valve open signal respectively at a display 10. |
