醫(yī)用超聲流量計(jì)標(biāo)定氣體流量控制系統(tǒng)的設(shè)計(jì)

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摘要 隨著科學(xué)技術(shù)的進(jìn)步和工業(yè)的發(fā)展,工程中對(duì)氣體流量的控制及測(cè)量精度的要求越來(lái)越高。但由于氣體的可壓縮性遠(yuǎn)大于液體的可壓縮性,氣體流量控制更是難以精確控制。傳統(tǒng)流量控制是通過(guò)改變流量控制閥的閥內(nèi)流道的最小截面積,從而改變流動(dòng)阻力的辦法來(lái)實(shí)現(xiàn)的。理論上,改變節(jié)流通道的面積,可線性調(diào)節(jié)流量。流量不只和節(jié)流面積有關(guān),實(shí)際上,節(jié)流面積的改變,也必然會(huì)使閥前后的壓差發(fā)生變化。這就導(dǎo)致相對(duì)開(kāi)度和相對(duì)流量之間的關(guān)系是不一定的,非線性的。通過(guò)調(diào)節(jié)閥芯開(kāi)度的方式來(lái)調(diào)節(jié)流量雖然不夠精確,而且不易實(shí)現(xiàn)自動(dòng)化控制[1]。但在實(shí)際應(yīng)用中,有時(shí)需要在一個(gè)系統(tǒng)中對(duì)流量實(shí)現(xiàn)自動(dòng)化控制。針對(duì)這種情況,構(gòu)建了一個(gè)氣體流量控制系統(tǒng)系統(tǒng)。氣體流量控制系統(tǒng)的設(shè)計(jì)，可用于系統(tǒng)中流量的自動(dòng)控制。
本課題完成了基于msp430單片機(jī)、IAR EWARM的總體方案和組成框架設(shè)計(jì)、硬件和軟件的設(shè)計(jì)，用于控制步進(jìn)電機(jī)進(jìn)而控制閥門工作。用戶通過(guò)用戶操作界面設(shè)定氣體流量控制裝置的各項(xiàng)參數(shù)，來(lái)實(shí)現(xiàn)想要的氣體流量速度。氣體流量自動(dòng)化控制系統(tǒng)設(shè)計(jì)使得用戶使用起來(lái)更加簡(jiǎn)便、直觀。
硬件電路主要包括信號(hào)的采集、單片機(jī)控制模塊。信號(hào)采集電路主要完成信號(hào)采集，放大，濾波功能，屬于典型的信號(hào)采集處理系統(tǒng)。處理對(duì)象，根據(jù)超聲流量計(jì)信號(hào)的特點(diǎn)，設(shè)計(jì)了前置放大電路。為更好的降低干擾的影響，設(shè)計(jì)了高通和低通濾波電路，成功提取了超聲流量計(jì)信號(hào)。微控制器電路通過(guò)A/D轉(zhuǎn)換把模擬信號(hào)轉(zhuǎn)換成數(shù)字信號(hào)送至微處理器做進(jìn)一步處理。
軟件部分主要完成超聲流量計(jì)信號(hào)存儲(chǔ)和處理等功能，開(kāi)發(fā)工具是IAR，采用C語(yǔ)言來(lái)編程。主程序通過(guò)調(diào)用各種子程序模塊完成特定的功能。子程序包括數(shù)據(jù)采集處理、步進(jìn)電機(jī)正反轉(zhuǎn)子程序、加速程序。

關(guān)鍵詞：氣體流量 控制系統(tǒng) 信號(hào)采集 步進(jìn)電機(jī)

The design of the control system using the medical ultrasonic flowmeter to calibrate gas flow
Abstract With the development of science and technique progress and industry, control and measurement accuracy of the gas flow in the project of the increasingly high demand. But due to the compressibility of gas is far greater than the compressibility of the liquid, gas flow control is even more difficult to precisely control. The control of traditional traffic is the minimum cross-sectional area to change the flow control valve of the valve flow, thus changing the flow resistance of the approach to the realization of the. In theory, change the throttle channel area, linear flow regulation. Flow not only,and the throttling area in fact, throttle area change, will also make the pressure valve before and after the change. This leads to the relationship of between relative opening and the relative flow is not necessarily, nonlinear.By adjusting the valve opening to regulate the flow though the way is not precise enough, and not easy to bring about auto-control. But in practical application, sometimes need in a system to bring about the automatic control of flow. In view of this situation, to build a system that can control the gas-flow . The design of gas-flow control system, can be used for automatic control system of flow.
This paper completes the overall plan of msp430 SCM, IAREWARM and the frame design, the design of hardware and software based on, for control of stepper motor and control valve. The user set parameters of gas-flow control device through the user interface, to achieve the gas-flow velocity wanted. The gas-flow automatic control system allows users to use more convenient, intuitive.
The hardware circuit mainly includes signal acquisition, MCU control module. The circuit of signal acquisition mainly completes signal acquisition, amplification, filtering function,which belongs to the typical signal acquisition and processing system. The treatment object, according to the characteristics of ultrasonic flowmeter signal, design the pre amplifier circuit. In order to reduce the interference effects,designing a wave filter of high and low pass, successfully extracted from ultrasonic flowmeter signal. The circuit of micro controller through the A/D converter converts the analog signal into digital signal is send to the microprocessor to further processing.
The software part mainly completes the signal storage of ultrasonic flowmeter and processing functions, development tools are IAR, using C language programming. Main program completed a variety of specific functions by calling the subroutine modules. Subroutine includes data acquisition and processing, man-machine interface program of stepper-motor and rotor program.

Keywords: gas-flow rate Control system signal acquisition stepper motor

目錄
第一章緒論 1
1.1課題研究的背景和意義 1
1.2國(guó)內(nèi)外研究現(xiàn)狀和發(fā)展 1
1.3本文的工作目標(biāo)及內(nèi)容 4
1.3.1本文主要工作 4
1.3.2論文結(jié)構(gòu)安排 4
第二章系統(tǒng)總體分析 5
2.1系統(tǒng)方案論證 5
2.2系統(tǒng)總體結(jié)構(gòu)設(shè)計(jì) 5
第三章硬件設(shè)計(jì) 6
3.1步進(jìn)電機(jī)分析 6
3.1.1步進(jìn)電機(jī)優(yōu)點(diǎn) 6
3.1.2步進(jìn)電機(jī)缺點(diǎn) 6
3.1.3步進(jìn)電機(jī)原理與機(jī)理 7
3.2單片機(jī)系統(tǒng) 9
3.2.1單片機(jī)定義 9
3.2.2單片機(jī)特點(diǎn) 9
3.2.3單片機(jī)選擇 9
3.3信號(hào)采集模塊 11
3.3.1信號(hào)檢測(cè)與傳感器 11
3.3.2前置放大電路 12-b..