| 摘要 |
PURPOSE:To make a zero-point adjustment perfectly by processing the quantity of zero-point correction measured when a flow rate is zero and the quantity of zero-point correction measured during flow rate measurement according to a specific equation, and calculating the quantity of zero-point correction. CONSTITUTION:A key SW is slanted up to a broken-line position to measure frequencies f01 and f02 proportional to the reciprocal of ultrasonic wave propagation time in the zero flow-rate state and the quantity DELTAf0 of zero-point correction, and they are stored in the memory in an arithmetic means 9. Then, frequencies f1 and f2 proportional to the reciprocal of ultrasonic propagation time and their difference DELTAf are inputted in the memory while a medium flows, and an arithmetic means 9 performs arithmetic based upon the equation to calculate the flow rate V of the medium and then calculate the quantity of the flow. In the equation, V is the flow rate, L is the distance in the medium, and N is a counted value.
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