| 摘要 |
PURPOSE:To detect the oil level accurately by setting a threshold value of an upper limit level comparator from an output of a lower limit level comparator from an output of a lower limit level photodetecting device and also setting a threshold value of a lower limit level comparator from an output of an upper limit level photodetecting device. CONSTITUTION:A threshold value of an upper limit level comparator 19 is set to be 1.5 times an output L of a lower limit level photodetecting device 14, while a threshold value of a lower limit level comparator 21 is set to be 0.75 times an output H of an upper limit level photodetecting device 12. The comparator 19 compares an output of a current-voltage converter 16 with the upper limit thresold value 1.5L, and the comparator 21 compares an output of a current-voltage converter 17 with the lower limit threshold value 0.75H. When the oil level in an oil container 10 is not larger than the lowest level, outputs of the comparators 19, 21 become 'H'. When the oil level exceeds the lowest level and is not larger than the uppermost level, the output of the comparator 21 is reveresed from 'H' to 'L'. Thereafter, if the oil level exceeds the uppermost level, the comparators 19, 21 generate 'L' outputs. Accordingly, when the output of the comparator 19 is 'L' and the output of the comparator 21 is 'H', the proper oil level is detected. |
