Design Of Ultrasonic Flowmeter Based On DSP

Flow is an important parameter of industrial measurement. Ultrasonic flowmeter, which has the advantages of non-contact measuring, non pressure loss, easy installation and maintenance, is a very popular flow measuring instrument in the last few years. Flow rate is calculated by measuring the time of ultrasonic passing through the fluid. But ultrasonic flowmeter is too expensive and its accuracy needs to be improved.On the basis of studying and analyzing relevant theories of ultrasonic flowmeter, a kind of ultrasonic flowmeter is designed based on the TMS20VC5509A(VC5509A for short), which is a high performance, low power 16 bits fixed-point DSP processor.The key of this design is obtaining the time difference. In this paper, the time difference is calculated by SCOT weighted generalized cross-correlation, which can guarantee the precision and has a sharp correlation peak. The system hardware consists of the following parts:signal processor-VC5509A, ultrasonic signal transmitter and receiver circuits, signal acquisition circuit based on ADS805, etc. Software of the system includes the DSP initializing program, ultrasonic transmitting and receiving program, implementation of Generalized Cross-Correlation algorithm.Finally, an experimental platform was built to test the designed ultrasonic flowmeter. Results show that the ultrasonic flowmeter has the features of good real-time performance, high precision, low power and low cost. This paper provides powerful foundation for further development and improvement of the ultrasonic flow measurements.