| 摘要 |
PURPOSE:To measure a water level with high accuracy by using two sparse and dense potentiometers in a float type water gauge. CONSTITUTION:By a potentiometer 1 of an (m) range, and a potentiometer 2 of a (cm) range, a water level variation of 0-10m is outputted as a resistance variation of 0-100%, and as a resistance variation of 0-100% by a turn-back method of 0-100cm, respectively. Outputs from the meters 1, 2 are converted to digital value, respectively through potentiometer converters 3, 4, and A/D converters 5, 6. In a selection control circuit 11, when a value of the (cm) range is within a range of 25-75cm, a selecting circuit 13 is allowed to select the output of a simple synthesizing circuit 7, and also, a selection reference value generating circuit 10 is allowed to derive the latest value of a difference between an output value of the circuit 7 and a value of the (m) range. On the other hand, when said value is out of the range, the circuit 10 is operated so as to add the difference between the output value of the circuit 7 and the value of the (m) range to the value of the latest (m) range, and to output it to a comparing and selecting circuit 12 as a selection reference value. In the circuit 12, from an output of a lead synthesizing circuit 8 and an output of a delay synthesizing circuit 9, that which is near the selection reference value is selected.
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