【摘要】：流程工業(yè)的三大測量要素分別為流量、溫度與壓力。隨著國內(nèi)西氣東輸項目的進展、城市天然氣管道化的建設、油田民用天然氣商品化政策的實施、化工生產(chǎn)原料流量的計量的需求、以及供水管道項目的日益增加使得流量計量儀表得到更廣泛的應用,并在國民經(jīng)濟的發(fā)展中逐步起到不可替代的作用。超聲波流量測量技術是一種應運而生的新技術,它利用超聲波信號在流體中傳播時所載流體的流速信息來測量流體流量,具有測量精度高、低流速性好、壓力損失小、適用范圍廣、測量范圍大等特點。本文設計了一種基于嵌入式ARM Cortex-M3內(nèi)核的STM32L超低功耗多聲道超聲波液體流量智能計量儀表,并開展了如下幾個方面的研究工作:(1)通過查閱大量相關文獻和資料,根據(jù)國內(nèi)外研究現(xiàn)狀,分析超聲波在介質(zhì)中的傳播特性,并研究超聲波換能器的工作原理,此外,詳細研究分析不同種類超聲波流量計的測量原理,并比較其優(yōu)勢和劣勢,分辨其適用場合,最后,根據(jù)設計要求,提出應用時差法來實現(xiàn)超聲波流量測量的設計方案。(2)在低功耗要求的前提下,提出基于嵌入式ARM Cortex-M3內(nèi)核的STM32L+TDC-GP22的設計方案,提出多聲道超聲波測量計的硬件電路的總體設計方案,根據(jù)各個模塊的技術要求,選擇芯片設計電路,并應用一定的抗干擾措施來提高測量精度。此外,通過多通道的回波信號自動增益調(diào)節(jié)和誤差修正算法來降低測量誤差,實現(xiàn)液體流量的高精度計量、存儲。并通過虛擬儀器技術實現(xiàn)數(shù)據(jù)在線監(jiān)控等功能。本文設計的多聲道超聲波流量計具有測量介質(zhì)可選、聲道數(shù)可選、計量精度高、功能可擴展性強、超低功耗等優(yōu)點。(3)軟件設計方面,采用模塊化設計方法,將整個系統(tǒng)分為4個模塊。提出軟件設計的總體流程圖,并分別設計時間測量程序,超聲波的發(fā)射、接收程序,中斷程序。分析了多聲道超聲波流量計的流量算法以及多聲道測量計算程序,從而完成對整個硬件系統(tǒng)的控制,并實現(xiàn)數(shù)據(jù)的處理和顯示等功能。(4)基于硬件電路設計和軟件控制流程,搭建基于虛擬儀器的實驗平臺,通過虛擬儀器技術實現(xiàn)數(shù)據(jù)在線監(jiān)控等功能。對所設計的多聲道超聲波流量計進行實驗測試。通過分析實驗結果,驗證本文所設計的超聲波流量計的正確性以及可行性,證明設計方案具有更高的測量精度。
[Abstract]:The three major measurement elements of the process industry are flow rate, temperature and pressure. With the progress of the West-to-East Gas Transmission Project in China, the construction of urban natural gas pipeline, the implementation of the commercial gas policy for civil oil fields, and the demand for the metering of raw material flow in chemical production, And the increasing number of water supply pipeline projects make the flow meter more widely used and gradually play an irreplaceable role in the development of national economy. Ultrasonic flow measurement is a new technology, which uses the velocity information of the fluid when the ultrasonic signal propagates in the fluid to measure the flow rate of the fluid. It has the advantages of high measuring accuracy, good low velocity and low pressure loss. Wide scope of application and wide range of measurement. In this paper, an intelligent measurement instrument of STM32L ultra-low power multi-channel ultrasonic liquid flow based on embedded ARM Cortex-M3 kernel is designed, and the following research work is carried out: (1) through consulting a lot of relevant literature and materials, According to the present research situation at home and abroad, the characteristics of ultrasonic wave propagation in medium are analyzed, and the working principle of ultrasonic transducer is studied. In addition, the measuring principle of different kinds of ultrasonic Flowmeter is analyzed in detail, and its advantages and disadvantages are compared. Finally, according to the design requirements, a design scheme of ultrasonic flow measurement based on the time difference method is proposed. (2) based on the requirement of low power consumption, the design scheme of STM32L TDC-GP22 based on embedded ARM Cortex-M3 kernel is proposed. The overall design scheme of the hardware circuit of the multi-channel ultrasonic meter is presented. According to the technical requirements of each module, the chip design circuit is selected, and some anti-interference measures are applied to improve the measuring accuracy. In addition, the multi-channel echo signal automatic gain adjustment and error correction algorithm are used to reduce the measurement error and realize the high precision measurement and storage of liquid flow. And through virtual instrument technology to realize data online monitoring and other functions. The multi-channel ultrasonic Flowmeter designed in this paper has the advantages of the choice of measuring medium, the number of sound channels, the high accuracy of measurement, the strong expansibility of function and the ultra-low power consumption. (3) in software design, the modular design method is used. The whole system is divided into four modules. The general flow chart of software design is presented, and time measuring program, ultrasonic transmitting program, receiving program and interrupt program are designed respectively. This paper analyzes the flow algorithm of multi-channel ultrasonic Flowmeter and the calculation program of multi-channel measurement, so as to complete the control of the whole hardware system and realize the functions of data processing and display. (4) based on the hardware circuit design and software control flow, The experiment platform based on virtual instrument is built, and the function of data online monitoring is realized through virtual instrument technology. The designed multi-channel ultrasonic Flowmeter is tested experimentally. Through the analysis of the experimental results, the correctness and feasibility of the ultrasonic Flowmeter designed in this paper are verified, and it is proved that the design scheme has higher measuring accuracy.
【學位授予單位】：河南工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TH814.92

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相關期刊論文 前1條

1 周愛國;阮杰陽;劉凱;陸敏恂;;超聲波流量計影響因素的分析及對策[J];中國工程機械學報;2009年04期

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本文編號：2223088