Study On A Measurement System To Oil Tanks Level Based On Ultrasonic And Virtual Instrument

The virtual instrument is a new way of development of measuringinstruments. Level measurement by ultrasonic is a kind of traditional andpotential methods. But, the high frequency of ultrasonic signal is required forhigh-speed data acquisition system. It can be well solved through high-speeddata acquisition system designed by LabVIEW the representative software ofvirtual instrument. In this paper, a measurement system to oil tanks level basedon ultrasonic and virtual instrument is researched. The design of emission andreceiving circuit, the weak signal detecting system and high-speed dataacquisition system is proposed.At the beginning, the development and characteristic of virtual instrumentas well as the status of level measurement technique are summarized. Thenvirtual instrument and the representative software LabVIEW are particularlyintroduced and virtual instrument designed method is studied.Secondly, the spreading character of ultrasonic signal is discussed. Theappropriate ultrasonic sensor is selected according to requirement, and thedesign of ultrasonic generation circuit and received circuit is proposed.Concerning about the characters of high frequency of ultrasonic signal, thedrive of data acquisition chip based on LabVIEW is studied, and a kind ofhigh-speed, multi- channel data sampling system with PC and its software aredesigned.Considering about the impact of the noise in the course of signalsreceiving, the chaotic oscillator and Duffing equation are studied in this paper.And the dynamical properties of the forced Duffing oscillator disturbed bysmall signal near the critical point of the non-equilibrium phase change isdiscussed, then the phase condition of the phase-change occurring is deduced.The weak signal detecting technology using intermittent chaotic theory ispresented. The experiment presented in this paper demonstrates that the usefulsignal from environmental noise can be distinguished clearly by this technology,and the feature can be extracted from the received signal. It has highersignal-to-noise ratios.Finally, a measurement system to oil tanks level based on ultrasonic andLabVIEW is developed. The software and hardware of system are designed.Then the error in system is analyzed, and the feasible methods are presented.