Design of the A/D Conversion Circuit Based on ARM for the Time-Difference Method Ultrasonic Flowmeter

Abstract:

Because the high precision ultrasonic flowmeter has shortcomings of expensive, the A/D conversion circuit based on ARM for the time-difference method ultrasonic flowmeter is designed. On the basis of time-difference method ultrasonic flowmeter theory and the domestic and overseas advanced technology, a cost-effective low-power 12-bit ADC12DL040 chip and ARM processor LPC2138 are chosen for the design. According to the data acquisition system issues of the time- difference method ultrasonic flowmeter, the two-channel 12-bit low-power monolithic CMOS analog-digital conversion chip is adopted to design the nanosecond-level high-resolution data acquisition system. In this paper, the A/D chip peripheral pin circuit design is given, hardware structure diagram and software flowchart are also given. The input frequency of ultrasonic signal is 400 kHz and the sampling frequency is 8MHz.The experimental results indicated that the designed A/D conversion circuit is able to accomplish the high-speed and high-resolution ultrasonic echo signal sampling; the minimum resolution time of A/D conversion circuit is 0.305ns. The physical map of A/D conversion circuit for the time-difference method ultrasonic flowmeter is presented. The design of A/D conversion circuit for time-difference method ultrasonic flowmeter not only lower the production cost, but also lays a solid foundation for the research of low-cost and high-precision time-difference method ultrasonic flowmeter.

• Periodical: Advanced Materials Research (Volumes 383-390)
• Pages: 516-523
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.383-390.516
• Online since: November 2011
• Authors: Xing Hong Zhang, Hui Zhang, Xi Hou Chen, Xian Quan Wang, Ji Qin Feng
• Keywords: A/D Converter, ARM, Data Acquisition (DAQ), Time-Difference Method (TDM), Ultrasonic Flowmeter

References

[1] Yu Wenfeng, The Hardware Circuit Realization Research on Time-difference-type Ultrasonic Flowmeter[D]. Harbin Engineering University, (2008).

[2] Halit Eren. Accuracy in Real Time ultrasonic Application and Transit-Time Flow Meters[J]. IEEE Instrumentation and Measurement Technology Conference, 1998, 18(21): 568-572.

DOI: 10.1109/imtc.1998.679856

[3] MANDARD E. KOUAME D. Transit time ultrasonic flowmeter: velocity profile estimation [J]. IEEE Ultrasonic Symposium, 2005, (02): 763-766.

DOI: 10.1109/ultsym.2005.1602963

[4] QIN Hao-yang, WU Shuang-yi, NING Ning. Background Calibration for Compensating Interstage Gain Errors in Pipelined A/D Converters [J]. Microelectronics, 2007, 37(03): 334-337.

[5] Wang X, Hurst P J, Lewis S H. A 12-bit 20-MS/s pipelined ADC with nested digital background calibration[C]. Proceedings of IEEE Custom Integrated Circuits Conference, Sep 21-24, 2003: 409-412.

DOI: 10.1109/cicc.2003.1249429

[6] Grace C R, Hurst P J, Lewis S H. A 12-b 80-MS/s pipelined ADC with bootstrapped digital calibration [J]. IEEE Journal of Solid-state Circuits, 2005, 40(05): 1038-1046.

DOI: 10.1109/jssc.2005.845972

[7] LIU Cun. Some improvement of travel time ultrasonic flowmeter [J]. Journal of Shenyang University of Technology, 2001(02): 25-27.

[8] DUAN Yun, WANG Rang-ding. A Modified Algorithm to Improve the Accuracy of Ultrasonic Flow-meter with Time Difference Method [J]. microelectronics & computer, H2009, (08): 45-48.

[9] B. Ioose, C. Lhuillier, H. jeanneau. Numerical simulation of transit-time ultrasonic flowmeters: uncertainties due to flow profile and fluid turbulence [J]. Ultrasonics, 2002, (40): 1009-1015.

DOI: 10.1016/s0041-624x(02)00387-6

[10] DUAN Hui-Ming. Application and prospect of ultrasonic flow measurement [J]. Measurement Technique, 1995(06) : 20-25.

[11] Li Guang-feng, Liu Fang, GaoYong. Accurate Measurement Technology of the Ultrasonic Flowmeter [J]. Chinese Journal of Scientific Instrument, H2001, (06)H: 644-647.

[12] ADC12DL040 Data Sheet, NS. 2005. 11. Hhttp: /www. national. com/pf/DC/ADC12DL040. html#DocumentsH.

[13] Xu Zhen-zhen, Design of Digital Electromagnetic Induction Measurement System[D]. Tianjin University, (2007).