Research Of An Ultrasonic Flowmeter Based On SOPC

At present, flow-meter has wide applications in chemical industry, metallurgy, oil-transportation, civilian water meters and civilian gas utilization. With the further development of ultrasonic technology, ultrasonic flow-meter is applied to the products as a new kind of flow measurement technology.With the current SOPC (System On Programmable Chip) technology and the advanced ultrasonic flow measurement technology at home and abroad, this paper has designed a kind of ultrasonic flow-meter based on SOPC technology and Cross-road transit time difference method, with a flow rate measurement from 5 m~3/h to 350 m~3/h, the measurement accuracy up to±2 % and the repeatability up to 1%.The design of the hardware and the software of the flow-meter in this paper has the following characteristics:The SOPC technology is adopted to implement the synergy of hardware and software design which not only maximizes the utilization of current IP in system design process, but also designs a functional IP for the system to achieve successful communication via bus. Thus the reliability of the circuit is improved as a result of the hardware circuit design simplification and the external interference reduction.The send-and-receive circuit which can well match launch, is also adopted to improve the circuit performance. And the dynamic range of the amplifier expands by well-designed program-controlled amplifier circuit. The noise interference is reduced by the means of band-pass filtering, threshold comparison, high-speed data collection and corresponding digital signal processing technology. The system performance is improved with the help of the software which can automatically adjust the correction coefficient of flow velocity.The window-receiving-delay technology is employed to reduce the impact of the interference pulse on measurement result. The system stability is improved by pulse width detection circuit to identify receive signals. This paper develops the program for communication with PC in VC++ language to monitor the meter.On-site tests showed that the operation of the system is stable and the measurement accuracy range is up to 2%, and lays a good foundation in developing the practical, high-performance ultrasonic flow-meter in the future.