Research Of The Measure Of Flow Velocity On Ultrasonic Flow Meter

The measurement of the flow is to guarantee the safe economical operation of the production process , improve product quality , reducing the foundation that the material consumes , increases economic efficiency , realizes scientific management. And the new electronic technology and introduction of the signal processing method in recent years, the momentum that is accelerating constantly is appearing in the development of this field, technology brings in constant renewal in, the range of application is being expanded constantly. What this text selects for use is ultrasonic flow meter. Ultrasonic flow meter contact-type instrument there is extensive application in order to his inherent advantage in the fields of petroleum , medicine , water resource management etc. its key parameter is the systematic precision of measurement.The article is on the basis of analysing the principle of the flow meter of ultrasonic wave and domestic and international products disparity at first, provide a kind of ultrasonic flow meter scheme based on bad law of phase place of improvement of DSP. The bad law of phase place is a kind of measurement method of the ultrasonic flow meter. This method requires that it should be accurate to pass the wave form constantly of the zero point by the signal of examining, in order to raise the precision that the system measures, this text has proposed calculating with the relevant algorithm that the phase place is bad, and make use of software inserting value to raise the time resolution ratio. Having introduced the inserting value principle, relevant principle, and how to raise the time resolution ratio with the inserting value algorithm and relevant algorithm. And then confirmed ultrasonic frequency , the choice of A/D , the speed that A/D samples, parameter of the respect of counting etc. that concrete to calculate out the point of sampling and inserting value. Main research work is as follows: Proceeding from relevant theory at first, programming has verified its exactness in MATLAB; Secondly has designed the hardware circuit of the whole system on this basis, among them the hardware system regards DSP chip TMS320VC5402 of TI Company as the core, because the signal processing speeds of DSP chip are quick , guarantee this precision of measurement with high system, the hardware including signal receive and amplifying, gather, store, show and DSP processor system in data; Then according to the systematic hardware circuit, have written the systematic software procedure under the enviroment of CCS again.The systematic hardware makes up including ultrasonic wave header , the circuit of the ultrasonic signal amplifies, the circuit of the digital signal deals with and the circuit of back end and serves. The part of the software realizes various kinds of algorithms with DSP.Result of software emulation verify feasibility of this scheme. The measurement to two sine wave that have certain phase difference have certain error at the experiment. The article provides the improvement suggestion of this system finally.