【正文】 35 附錄：英文資料及譯文 The Integrated Circuit Digital logic and electronic circuits derive their functionality from electronic switches called transistor. Roughly speaking, the transistor can be likened to an electronically controlled valve whereby energy applied to one connection of the valve enables energy to flow between two other bini ng multiple transistors, digital logic building blocks such as AND gates and flipflops are formed. Transistors, in turn, are made from semiconductors. Consult a periodic table of elements in a college chemistry textbook, and you will locate semiconductors as a group of elements separating the metals and are called semiconductors because of their ability to behave as both metals and nonmetals. A semiconductor can be made to conduct electricity like a metal or to insulate as a nonmetal does. These differing electrical properties can be accurately controlled by mixing the semiconductor with small amounts of other elements. This mixing is called doping. A semiconductor can be doped to contain more electrons (Ntype) or fewer electrons (Ptype). Examples of monly used semiconductors are silicon and germanium. Phosphorous and boron are two elements that are used to dope Ntype and Ptype silicon, respectively. A transistor is constructed by creating a sandwich of differently doped semiconductor layers. The two most mon types of transistors, the bipolarjunction transistor (BJT) and the fieldeffect transistor (FET) are schematically illustrated in Figure figure shows both the silicon structures of these elements and their graphical symbolic representation as would be seen in a circuit diagram. The BJT shown is an NPN transistor, because it is posed of a sandwich of NPN doped silicon. When a small current is injected into the base terminal, a larger current is enabled to flow from the collector to the FET shown is an Nchannel FET, which is posed of two Ntype regions separated by a Ptype substrate. When a voltage is applied to the insulated gate terminal, a current is enabled to flow from the 36 drain to the source. It is called Nchannel, because the gate voltage induces an Nchannel within the substrate, enabling current to flow between the Nregions. Another basic semiconductor structure is a diode, which is formed simply by a junction of Ntype and Ptype silicon. Diodes act like oneway valves by conducting current only from P to N. Special diodes can be created that emit light when a voltage is applied. Appropriately enough, these ponents are called light emitting diodes, or LEDs. These small lights are manufactured by the millions and are found in diverse applications from telephones to traffic lights. The resulting small chip of semiconductor material on which a transistor or diode is fabricated can be encased in a small plastic package for protection agai nst damage and contamination from the out side wires are connected within this package between the semiconductor sandwich and pins that protrude from the package to make electrical contact with other parts of the intended circuit. Once you have several discrete transistors, digital logic can be built by directly wiring these ponents together. The circuit will function, but any substantial amount of digital logic will be very bulky, because several transistors are required to implement each of the various types of logic gates. At the time of the invention of the transistor in 1947 by John Bardeen, Walter Brattain, and William Shockley, the only way to assemble multiple transistors into a single circuit was to buy separate discrete transistors and wire them together. In 1959, Jack Kilby and Robert Noyce independently invented a means of fabricating multiple transistors on a single slab of semiconductor material. Their invention would e to be known as the integrated circuit, or IC, which is the foundation of our modern puterized world. An IC is so called because it integrates multiple transistors and diodes onto the same small semiconductor chip. Instead of having to solder individual wires between discrete ponents, an IC contains many small ponents that are already wired together in the desired topology to form a circuit. A typical IC, without its plastic or ceramic package, is a square or rectangular silicon die measuring from 2 to 15 mm on an edge. Depending on the level of technology used to manufacture the IC, there may be anywhere from a dozen to tens 37 。設(shè)計很多關(guān)鍵的地方我都是靠和同學(xué)的請教和討論才能順利完成，因此，同學(xué)的幫助也是我完成畢業(yè)設(shè)計的一個重要支撐。母校對我的栽培不僅讓我學(xué)會了科學(xué)知識，更重要的是幫助我學(xué)會了如何去學(xué)習(xí)，如何去把學(xué)到的知識應(yīng)用到實際的生活中，這對我畢業(yè)后的生活和工作是一筆巨大的財富。如果沒有老師幫助我解決在設(shè)計過程中困惑，我 也很難順利完成這次畢業(yè)設(shè)計。在串級液位控制仿真過程中同時可整定 PID 參數(shù)，通過不斷調(diào)節(jié)PID 參數(shù)，得到滿意的響應(yīng)曲線，使得其響應(yīng)速度快，超調(diào)量小，穩(wěn)態(tài)誤差小。 水箱數(shù)學(xué)模型的建立是設(shè)計的開始和關(guān)鍵，通過采集的數(shù)據(jù)在 MATLAB 上通過數(shù)據(jù)擬合得到各水箱階躍曲線，然后通過曲線可得到各水箱的一階傳遞函數(shù)中的參數(shù) K 和 T,進(jìn)而可得到三容水箱的傳遞函數(shù)。 本次畢業(yè)設(shè)計，結(jié)合所學(xué)的知識以及參考的資料， 著重研究了三容水箱串級控制建 模方法，串級控制系統(tǒng)的設(shè)計和 MATLAB 仿真，最終實現(xiàn)了對水箱液位的控制。 32 6 結(jié)論 液位是工業(yè)生產(chǎn)過程中重要的被控量之一，因而液位控制的研究具有很大的現(xiàn)實意義。 31 3）在儀表控制系統(tǒng)中，一般是一個控制器控制一個回路，而在計算機(jī)控制系統(tǒng)中，由于計算機(jī)具有高速運(yùn)算的能力，一個控制器（控制 計算機(jī)）經(jīng)常采用分時控制的方式同時控制多個回路。 2）儀表控制系統(tǒng)，控制規(guī)律由硬件實現(xiàn)，要修改控制規(guī)律，必須要改變硬件結(jié)構(gòu)，如 AI 智能調(diào)節(jié)儀。所以說，控制器是過程控制系統(tǒng)的關(guān)鍵，控制規(guī)律的確定和控制器參數(shù)的整定是系統(tǒng)設(shè)計中最重 要的環(huán)節(jié)。D=0 調(diào)節(jié)器 1 的設(shè)定值為 7cm,突加階躍后設(shè)定值到 8cm,此時超調(diào)量為 25%，調(diào)整時間為 8分鐘（ 2%誤差帶），穩(wěn)態(tài)誤差 0。D=0 調(diào)節(jié)器 3的參數(shù) :P=20。D=25 調(diào)節(jié)器 2的參數(shù) :P=30。 30 圖 遠(yuǎn)程計算機(jī)系統(tǒng)突加階躍過渡過程曲線 PID參數(shù)： 調(diào)節(jié)器 1的參數(shù) :P=70。提供了 WWW瀏覽功能，能夠方便地實現(xiàn)生產(chǎn)現(xiàn)場控制與企業(yè)管理的集成。強(qiáng)大的網(wǎng)絡(luò)功能，支持 TCP/IP、 Modem、 485/422/232，以及各種無線網(wǎng)絡(luò)和無線電臺等多種網(wǎng)絡(luò)體系結(jié)構(gòu)。完善的安全機(jī)制，允許用戶自由設(shè)定菜單、按鈕及退出系統(tǒng)的操作權(quán)限。強(qiáng)大的數(shù)據(jù)處理功能，能夠?qū)I(yè)現(xiàn)場產(chǎn)生的數(shù)據(jù)以各種方式進(jìn)行統(tǒng)計處理，使您能夠在第一時間獲得有關(guān)現(xiàn)場情況的第一手?jǐn)?shù)據(jù)。支持目前絕大多數(shù)硬件設(shè)備，同時可以方便地定制各種設(shè)備驅(qū)動；此外，獨特的組態(tài)環(huán)境調(diào)試功能與靈活的設(shè)備操作命令相結(jié)合，使硬件設(shè)備與軟件系統(tǒng)間的配合天衣無縫。龐大的標(biāo)準(zhǔn)圖形庫、完備的繪圖工具以及豐富的多媒體支持，使您能夠快速地開發(fā)出集圖像、聲音、動畫等于一體的漂亮、生動的工程畫面。 MCGS 具有操作簡便、可視性好、可維護(hù)性強(qiáng)、高性能、高可靠性等突出特點，已成功應(yīng)用于石油化工、鋼鐵行業(yè)、電力系統(tǒng)、水處理、環(huán)境監(jiān)測、機(jī)械制 造、交通運(yùn)輸、能源原材料、農(nóng)