The Development Of Dynamic And Correcting By Itself Ultrasonic Liquid Level Measuring System

Liquid level measuring is related with robotization closely, and almost spreads over all fields of producing and living. In recent years, because of the development and application of new measure principle and micro-electronics technique, the liquid level measuring instruments become more miniature and more intelligentized. They gradually realize fault diagnosis and alarm, high precision, high reliability, high safety and multi-function.Ultrasonic liquid level measurement is a kind of traditional but having potential's methods. At present, domestic ultrasonic liquid level measurings mostly adopt air-medium principle, partly too adopt liquid-medium principle. Because of the limit to frequency or velocity correcting, their application field and measure precision are not very ideal. Moreover, these traditional methods can not be applied in the circumstance with gradient liquid surface, especially the dynamic and narrow-space equip, such as airplane and tank. But the agility due to mobile and the vacuum efficiency due to narrowness are very important to military.Opposite to the traditional static ultrasonic liquid level measurement, one dynamic and correcting by itself ultrasonic liquid level measurement technique, which is introduced in this thesis, has performance such as: small near limit, high precision, easy communicating, and so on. This thesis emphasizes the measuring principle. Through adopting the special pipe to retrain and manage liquid, it has solved the liquid inclining and speed correcting by oneself from the measuring principle. One hand, it extends the ultrasonic measure to dynamic; On the other hand it can roundly correct velocity in all kinds of liquid medium.Due to these correcting devices, the signal of ultrasonic echo waves becomes relatively complicated. Compare to the traditional threshold method to distinguish the signal and detect the time, complete data sampling is adopted. And in this thesis, these follow content are introduced in detail. On the aspect of hardware, they include: narrow pulse and high frequency ultrasonic sensor's design, high frequency signal generator and receiver's design, high speed data completed sampling's design. And on the aspect of software, they include: identifying the correcting signal and surface signal, then real-time calculate the velocity by these data of correcting signal, and final accurate calculating the liquid level. Moreover, serial communication and analog current transmission are adopted to meet the need of buildup measuring network.