The Control Module Design, Based On Ultrasonic Flowmeter Of The Adsp-bf531

Ultrasonic flow meter is widely used in oil, gas and chemical industry because of its advantages of non-contact measurement, ease installation, low cost and so on. With the development of micro-processing technology in recent years, ultrasonic flow meter can improve the measurement accuracy on real-time basis by applying more complex software algorithms on the new type micro-processor.By researching on plenty of data, we put forward a DSP-core ultrasonic flowmeter's measurement and control module with Time-difference method. On the basis of using DSP processor to realize the ultrasonic transceiver control, it makes full use of DSP digital signal processing capability to measure the velocity information. Compared to the previous implementation methods, on the one hand, it eliminates the bottleneck that the measurement relies on the hardware detection; On the other hand,by using a separate processor to control and process signal, it greatly simplifies the system circuit.The hardware system design in the module is around the core of ADSP-BF531 from Analog Device Company, including designs of the amplifier circuit, filter circuit, automatic gain control circuit, analog-digital conversion circuit, digital-analog conversion circuit, voltage conversion circuit, and some peripheral circuits'design of ADSP-BF531. Among this, automatic gain control circuit, analog-digital conversion circuit, ADSP-BF531 and digital-analog conversion circuit and some others build up an automatic gain control system which can stabilize ultrasonic signal amplitude after the digital filtering in order to promote the effective realization of the software detection algorithm. The hardware system is a mixed-signal circuit, by reasonable layout and wiring when designing PCB boards can effectively eliminate the interference noise.Calculate the arrival time of ultrasound by linear interpolation algorithm used in ADSP-BF531, and then we can get velocity information. Before test the ultrasonic propagation time, we also use the digital filtering algorithm in the sampled signal to better eliminate noise and improve accuracy. By using the peak detection algorithm in automatic gain control algorithm, we make use of the signal energy to measure the peak value of ultrasonic signal quickly and efficiently. Because the experimental conditions are limited, temporarily we are unable to give specific precision of the measurement and control module in flow measurement application. By the experiment of measuring the spreading time on the measurement and control module, it is proved to have a good effect. Finally, we offer suggestions for improvement of the control module.