| 摘要 |
<p>A time difference type ultrasonic flowmeter measurement method based on zero point analysis, being a method for accurately determining concurrent and countercurrent transmission time by zero point analysis, the method comprising: (1) after sending a pulse drive signal, starting A/D conversion to collect data; (2) searching for a zero point value; (3) selecting at least three neighboring zero crossing points, and determining whether the three neighboring zero crossing points are ultrasonic signal zero crossing points; (4) selecting a first zero crossing point in an ultrasonic receiving signal to determine the arrival time of an ultrasonic signal, and calculating the concurrent and countercurrent transmission time; (5) calculating the instantaneous flow rate of a measured cross section according to the concurrent and countercurrent transmission time. The ultrasonic signal zero point of the present invention is not affected by the external environment, so even in the case of weak signals, large fluctuation and strong interference, a zero point can be detected, and the concurrent and countercurrent transmission time of an ultrasonic signal in fluid can be accurately measured, thus greatly improving the measurement accuracy of a time difference type ultrasonic flowmeter.</p> |
