ULTRASONIC FLOWMETER AND METHOD FOR MEASURING FLOW RATE
To suppress output of a wrong flow rate by an ultrasonic flowmeter.SOLUTION: A threshold value adjusting unit 107 calculates the degree of a measurement voltage Vin#i where a top zero-cross point measured first corresponds to a follow zero-cross point located before a target zero-cross point by a pr...
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| Format: | Patent |
| Sprache: | eng ; jpn |
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| Zusammenfassung: | To suppress output of a wrong flow rate by an ultrasonic flowmeter.SOLUTION: A threshold value adjusting unit 107 calculates the degree of a measurement voltage Vin#i where a top zero-cross point measured first corresponds to a follow zero-cross point located before a target zero-cross point by a predetermined cycle, and adjusts a threshold voltage Vs on the basis of the result of comparison between the degree and a preset threshold value. A determination unit 108 determines the presence of a peak lost where the target zero-cross point may not be specified when the degree is 0 or 1.SELECTED DRAWING: Figure 1
【課題】超音波流量計で誤った流量の出力を抑制する。【解決手段】閾値調整部１０７は、計測電圧Ｖｉｎ＃ｉのうち、最初に計測された先頭ゼロクロス点が、予め定めた周期分だけ目標ゼロクロス点の前に位置する追従ゼロクロス点に相当する、計測電圧Ｖｉｎ＃ｉの度合を計算し、度合と予め設定されている閾値との比較結果に基づいて閾値電圧Ｖｓを調整する。判定部１０８は、度合が０または１となると、目標ゼロクロス点の特定ができないピークロストと判定する。【選択図】 図１ |
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