外文翻譯---單片機系統(tǒng)

1、<p><b>　　附錄C 外文文獻</b></p><p>　　Microcomputer Systems</p><p>　　Electronic systems are used for handing information in the most general sense; this information may be telephone c

2、onversation, instrument read or a company’s accounts, but in each case the same main type of operation are involved: the processing, storage and transmission of information. in conventional electronic design these operat

3、ions are combined at the function level; for example a counter, whether electronic or mechanical, stores the current and increments it by one as required. A system su</p><p>　　Present day microprocessor base

4、d systems depart from this conventional approach by separating the three functions of processing, storage, and transmission into different section of the system. This partitioning into three main functions was devised by

5、 Von Neumann during the 1940s, and was not conceived especially for microcomputers. Almost every computer ever made has been designed with this structure, and despite the enormous range in their physical forms, they have

6、 all been of essentially the </p><p>　　In a microprocessor based system the processing will be performed in the microprocessor itself. The storage will be by means of memory circuits and the communication of

7、 information into and out of the system will be by means of special input/output(I/O) circuits. It would be impossible to identify a particular piece of hardware which performed the counting in a microprocessor based clo

8、ck because the time would be stored in the memory and incremented at regular intervals but the microprocessor. H</p><p>　　The figure1.1 illustrates how these three sections within a microcomputer are connect

9、ed in terms of the communication of information within the machine. The system is controlled by the microprocessor which supervises the transfer of information between itself and the memory and input/output sections. The

10、 external connections relate to the rest (that is, the non-computer part) of the engineering system.</p><p>　　Fig.1.1 Three Sections of a Typical Microcomputer</p><p>　　Although only one storage

11、 section has been shown in the diagram, in practice two distinct types of memory RAM and ROM are used. In each case, the word ‘memory’ is rather inappropriate since a computers memory is more like a filing cabinet in con

12、cept; information is stored in a set of numbered ‘boxes’ and it is referenced by the serial number of the ‘box’ in question. </p><p>　　Microcomputers use RAM (Random Access Memory) into which data can be wr

13、itten and from which data can be read again when needed. This data can be read back from the memory in any sequence desired, and not necessarily the same order in which it was written, hence the expression ‘random’ acces

14、s memory. Another type of ROM (Read Only Memory) is used to hold fixed patterns of information which cannot be affected by the microprocessor; these patterns are not lost when power is removed and are normally</p>

15、<p>　　The microprocessor processes data under the control of the program, controlling the flow of information to and from memory and input/output devices. Some input/output devices are general-purpose types while o

16、thers are designed for controlling special hardware such as disc drives or controlling information transmission to other computers. Most types of I/O devices are programmable to some extent, allowing different modes of o

17、peration, while some actually contain special-purpose microprocessors to</p><p>　　The microprocessor processes data under the control of the program, controlling the flow of information to and from memory an

18、d input/output devices. Some input/output devices are general-purpose types while others are designed for controlling special hardware such as disc drives or controlling information transmission to other computers. Most

19、types of I/O devices are programmable to some extent, allowing different modes of operation, while some actually contain special-purpose microprocessors to</p><p>　　The microprocessor , memory and input/outp

20、ut circuit may all be contained on the same integrated circuit provided that the application does not require too much program or data storage . This is usually the case in low-cost application such as the controllers us

21、ed in microwave ovens and automatic washing machines . The use of single package allows considerable cost savings to e made when articles are manufactured in large quantities . As technology develops , more and more powe

22、rful processors an</p><p>　　Another major engineering application of microcomputers is in process control. Here the presence of the microcomputer is usually more apparent to the user because provision is nor

23、mally made for programming the microcomputer for the particular application. In process control applications the benefits lf fitting the entire system on to single chip are usually outweighed by the high design cost invo

24、lved, because this sort lf equipment is produced in smaller quantities. Moreover, process controllers</p><p>　　The working instruments in the plant usually include simple pressure gauges, precision recorders

25、 and indicators, and pneumatic and electronic pressure transmitters. A pressure transmitter makes a pressure measurement and generates either a pneumatic or electrical signal output that is proportional to the pressure b

26、eing sensed.</p><p>　　In the process plant, it is impractical to locate the control instruments out in the place near the process. It is also true that most measurements are not easily transmitted from some

27、remote location. Pressure measurement is an exception, but if a high pressure of some dangerous chemical is to be indicated or recorded several hundred feet from the point of measurement, a hazard may be from the pressur

28、e or from the chemical carried.</p><p>　　To eliminate this problem, a signal transmission system was developed. This system is usually either pneumatic or electrical. And control instruments in one location.

29、 This makes it practical for a minimum number of operators to run the plant efficiently.</p><p>　　When a pneumatic transmission system is employed, the measurement signal is converted into pneumatic signal b

30、y the transmitter scaled from 0 to 100 percent of the measurement value. This transmitter is mounted close to the point of measurement in the process. The transmitter output-air pressure for a pneumatic transmitter-is pi

31、ped to the recording or control instrument. The standard output range for a pneumatic transmitter is 20 to 100kPa, which is almost universally used.</p><p>　　When an electronic pressure transmitter is used,

32、the pressure is converted to electrical signal that may be current or voltage. Its standard range is from 4 to 20mA DC for current signal or from 1 to 5V DC for voltage signal. Nowadays, another type of electrical signal

33、, which is becoming common, is the digital or discrete signal. The use of instruments and control systems based on computer or forcing increased use of this type of signal.</p><p>　　Sometimes it is important

34、 for analysis to obtain the parameters that describe the sensor/transmitter behavior. The gain is fairly simple to obtain once the span is known. Consider an electronic pressure transmitter with a range of 0～600kPa.The g

35、ain is </p><p>　　defined as the change in output divided by the change in input. In this case, the output is electrical signal (4～20mA DC) and the input is process pressure (0～600kPa). Thus the gain. Beside

36、we must measure Temperature Temperature measurement is important in industrial control, as direct indications of system or product state and as indirect indications of such factors as reaction rates, energy flow, turbine

37、 efficiency, and lubricant quality. Present temperature scales have been in use for about </p><p>　　Advantages of electrical systems include high accuracy and sensitivity, practicality of switching or scann

38、ing several measurements points, larger distances possible between measuring elements and controllers, replacement of components(rather than complete system), fast response, and ability to measure higher temperature. Amo

39、ng the electrical temperature sensors, thermocouples and resistance temperature detectors are most widely used.</p><p>　　附錄D 外文文獻中文翻譯</p><p><b>　　單片機系統(tǒng)</b></p><p>　　廣義地

40、說，微處理系統(tǒng)是用于處理信息的，這種信息可以是電話交談，儀器讀數(shù)或企業(yè)帳戶，但是各種情況下都涉及相同的主要操作：信息處理、存儲和傳遞。在常規(guī)的電子設(shè)計中，這些操作都是以功能平臺方式組合起來的，例如計數(shù)器，無論是電子還是機械的，都要存儲當(dāng)前值，并按要求將該值增1。諸如采用計數(shù)器的電子鐘之類的任一系統(tǒng)要使其存儲和處理能力遍布整個系統(tǒng)，因為每個計數(shù)器都能存儲和處理一些數(shù)字。</p><p>　　當(dāng)前微處理化系統(tǒng)與上述的

41、常規(guī)方法不同，它將處理，存儲和傳輸三個功能分離形成不同的系統(tǒng)單元。這種形成三個主要單元的分離方法是馮-諾依曼在20世紀40年代所設(shè)想出來的，并且是針對微計算機的設(shè)想。從此幾乎所有制成的計算機都是用這種結(jié)構(gòu)設(shè)計的，盡管包含寬廣的物理形式，從根本上來說他們均是具有相同的基本設(shè)計。</p><p>　　在微處理器系統(tǒng)中，處理是由微處理器本身完成的。存儲是利用存儲器電路，而進入和出自系統(tǒng)的信息傳輸則是利用特定的輸入/輸出

42、（I/O）電路。要在一個微處理器化時鐘中找出執(zhí)行計數(shù)功能的一個特殊硬件是不可能的，因為時間存儲在存儲器中，而在固定的時間間隔下由微處理器控制增值。但是，規(guī)定系統(tǒng)運轉(zhuǎn)過程的軟件包含實現(xiàn)計數(shù)器功能的單元。由于系統(tǒng)幾乎完全由軟件所定義，所以對微處理器結(jié)構(gòu)和其輔助電路這種看起來非常抽象的處理方法使其在應(yīng)用時非常靈活。這種設(shè)計過程主要是軟件工程，而且在生產(chǎn)軟件時，就會遇到產(chǎn)生于常規(guī)工程中相似的構(gòu)造和維護問題。</p><p&g

43、t;　　圖1.1 微型計算機的三個組成部分</p><p>　　圖1.1顯示出了微型計算機中這三個單元是如何按照機器中的信息通信方式而聯(lián)接起來的。該系統(tǒng)由微處理器控制，它管理自己與存儲器和輸入/輸出單元的信息傳輸。外部的連接與工程系統(tǒng)的其余部分（即非計算機部分）有關(guān)。</p><p>　　盡管圖中顯示的只有一個存儲單元，實際中有RAM和ROM兩種不同的存儲器被使用。由于概念上的計算機存儲器

44、更像一個公文柜，上述的“存儲器”一詞是非常不恰當(dāng)?shù)?；信息存放在一系列已?biāo)號的“箱子”中，而且可按問題由“箱子”的序列號進行信息的參考定位。</p><p>　　微計算機常使用RAM（隨機存取存儲器），在RAM中數(shù)據(jù)可被寫入，并且在需要時可被再次讀出。這種數(shù)據(jù)能以任一所希望的次序從存儲器中讀出，不必按寫入時的相同次序，所以有“隨機”存取存儲器。另一類型ROM（只讀存儲器）用來保持不受微處理器影響的固定的信息標(biāo)本；這

45、些標(biāo)本在電源切斷后不會丟失，并通常用來保存規(guī)定微處理器化系統(tǒng)運轉(zhuǎn)過程的程序。ROM可像RAM一樣被讀取，但與RAM不一樣的是不能用來存儲可變的信息。有些ROM在制造時將其數(shù)據(jù)標(biāo)本放入，而另外的則可通過特殊的設(shè)備由用戶編程，所以稱為可編程ROM。被廣泛使用的可編程ROM可利用特殊紫外線燈察除，并被成為EPROM，即可察除可編程只讀存儲器的縮寫。另有新類型的期器件不必用紫外線燈而用電察除，所以稱為電可察除可編程只讀存儲器EEPROM。<

46、;/p><p>　　微處理器在程序控制下處理數(shù)據(jù)，并控制流向和來自存儲器和輸入/輸出裝置的信息流。有些輸入/輸出裝置是通用型的，而另外一些則是設(shè)計來控制如磁盤驅(qū)動器的特殊硬件，或控制傳給其他計算機的信息傳輸。大多數(shù)類型的I/O裝置在某種程度下可編程，允許不同形式的操作，而有些則包含特殊用途微處理器的I/O裝置不用主微處理器的直接干預(yù)，就可實施非常復(fù)雜的操作。</p><p>　　假如應(yīng)用中不需

47、要太多的程序和數(shù)據(jù)存儲量，微處理器、存儲器和輸入/輸出可全被包含在同一集成電路中。這通常是低成本應(yīng)用情況，例如用于微波爐和自動洗衣機的控制器。當(dāng)商品被大量地生產(chǎn)時，這種單一芯片的使用就可節(jié)省相當(dāng)大的成本。當(dāng)技術(shù)進一步發(fā)展，更強更強的處理器和更大更大數(shù)量的存儲器被包含形成單片微型計算機，結(jié)果使最終產(chǎn)品的裝配成本得以節(jié)省。但是在可預(yù)見的未來，當(dāng)需要大量的存儲器或輸入/輸出時，還是有必要繼續(xù)將許多集成電路相互聯(lián)結(jié)起來，形成微計算機。</

48、p><p>　　微計算機的另一主要工程應(yīng)用是在過程控制中。這是，由于裝置是按特定的應(yīng)用情況由微機編程實現(xiàn)的，對用戶來說微計算機的存在通常就更加明顯。在過程控制應(yīng)用中，由于這種設(shè)備以較少的數(shù)量生產(chǎn)，將整個系統(tǒng)安裝在單個芯片上所獲取的利益常比不上所涉及的高設(shè)計成本。而且，過程控制器通常更為復(fù)雜，所以要將他們做成單獨的集成電路就更為困難。可采用兩種處理，將控制器做成一種通用的微計算機，正像較強版本的業(yè)余計算機那樣；或者做成

49、“包裹”式系統(tǒng)，按照像電磁繼電器那樣的較老式的技術(shù)進行設(shè)計，來取代控制器。對前一種情況，系統(tǒng)可以用常規(guī)的編程語言來編程，正如以后要介紹的語言那樣；而另一種情況，可采用特殊用途的語言，例如那種使控制器功能按照繼電器相互連接的方法進行描述。兩種情況下，序均能存于RAM，這讓程序能按應(yīng)用情況變化時進行相應(yīng)的變化，但是這使得總系統(tǒng)易受掉電影響而工作不正常，除非使用電池保證供電連續(xù)性。另一種選擇是將程序在ROM中，這樣他們就變成電子“硬件”的一部

50、分并常被稱為“固件”。</p><p>　　盡管大規(guī)模集成電路的應(yīng)用使小型和微型計算機的差別變得“模糊”，更復(fù)雜的過程控制器需要小型計算機實現(xiàn)他們的過程。各種類型的產(chǎn)品和過程控制器代表了當(dāng)今微計算機應(yīng)用的廣泛性，而具體的結(jié)構(gòu)取決于對“產(chǎn)品”一詞的解釋。實際上，計算機的所有工程和科學(xué)上的應(yīng)用都能指定來進行這些種類的某一或某些工作。而在本設(shè)計中壓力和壓力變送器當(dāng)某一力加到某一面積上，就形成壓力，假如這力是1牛頓均勻地

51、加在1平方米的面積上，這壓力被定義為1帕斯卡。壓力是一種普遍的工藝狀態(tài)，它也是這個星球上的一個生活條件：我們生活在向上延伸許多英里的大氣海洋的底部?？諝馕镔|(zhì)是有重量的，而且這種下壓的重量形成大氣壓。水，是生活的必需品，也是在壓力之下提供給我們中的大多數(shù)人。在典型的過程工廠中，壓力影響沸點溫度、凝固點溫度、過程效率、消耗和其他重要因數(shù)。壓力的測量和控制，或者壓力的不足—真空，在典型的過程控制中是極為重要的。</p><

52、p>　　工廠中的工作儀器通常包括壓力計、精密紀錄儀、以及氣動和電動的壓力變送器。壓力變送器實現(xiàn)壓力測量并產(chǎn)生正比于所傳感壓力的氣動或電信號輸出。</p><p>　　在過程工廠中，將控制儀表遠遠放在過程的附近是不現(xiàn)實的，并且大多數(shù)測量是不容易從遠處傳來的。壓力測量是一個例外，但是，如果要離測量點幾百英尺外指示或記錄某種危險化學(xué)品的高壓，就會有來自這個壓力所載的化學(xué)品所引發(fā)的危險。為了消除這一問題，開發(fā)了一種

53、信號傳輸系統(tǒng)。這種系統(tǒng)常?？墒菤鈩踊蛘唠妱拥?。使用這種系統(tǒng)，就可以在某一地點安裝大多數(shù)的指示、記錄和控制儀器。這也是最少數(shù)量的操作者有效的運行工廠成為現(xiàn)實。</p><p>　　當(dāng)使用氣動傳送系統(tǒng)時，測量信號就由變送器將比例為0%～100%的測量值轉(zhuǎn)換為氣動信號。變送器安裝在靠近過程中的測量點上。變送器輸出—對氣動變送器是輸出壓力—通過管道傳給記錄或控制儀表。氣動變送器的標(biāo)準輸出范圍是20～100kPa，這信號幾

54、乎在全球使用。</p><p>　　當(dāng)使用電子壓力變送器時，壓力就被轉(zhuǎn)換成電流或電壓形式的電信號。其標(biāo)準范圍對電流來說是4～20mA DC，對電壓信號來說是1～5V DC。當(dāng)今，另一種電信號形式變的越來越常用，就是數(shù)字或離散信號?；谟嬎銠C或微處理器的儀器或控制系統(tǒng)的應(yīng)用正推動這類信號的應(yīng)用不斷增加。有時，分析獲取描述傳感器/變送器特性的參數(shù)是很重要的。當(dāng)量程已知，去獲取增益就非常簡單。假定電子壓力傳感器的量程為

55、0～600kPa，增益定義為輸出變化除以輸入變化。這里，輸出的電信號（4～20mA DC），而輸入的過程壓力（0～600kPa），這樣增益就為：</p><p>　　此外我們在本設(shè)計中還必須對溫度進行測量，溫度測量在工業(yè)控制中是很重要的，因為它作為系統(tǒng)或產(chǎn)品狀態(tài)的直接指標(biāo)，或者作為如反應(yīng)率、能量流、渦輪機效率和潤滑質(zhì)量等間接指標(biāo)?，F(xiàn)行的溫度分度已使用了約200年，最初的儀器是基于氣體和液體的熱膨脹?，F(xiàn)在盡管有許多

56、其他類型的儀器在使用，這些填充式系統(tǒng)仍常用于直接的溫度測量。有代表性的溫度傳感器包括：填充式熱系統(tǒng)、玻璃液體溫度計、熱電偶、電阻溫度探測器、熱敏電阻、雙金屬器件、光學(xué)和輻射高溫計和熱敏涂料。</p><p>　　電氣系統(tǒng)的優(yōu)點包括高的精度和靈敏度，能實現(xiàn)開關(guān)切換或掃描多個測量點，可在測量元件和控制器之間長距離傳輸，出現(xiàn)事故時可調(diào)換元件，快速響應(yīng)，以及具有測量高溫的能力。其中熱電偶和電阻溫度探測器則被最廣泛的使用。