外文翻譯--變頻器和單片機的基本知識

1、<p>　　Basic Knowledge of Inverters and Single-chip</p><p>　　Frequency AC motor speed control used as the principal means have been used in a wide range of applications in the industrial area .It has

2、a wide range of speed, steady speed and high precision, fast dynamic response for a wide range of technical performance and reliable operation has been gradually replace the DC motor speed control system. There are thre

3、e main control types of inverter: first,through the operator panel inverter, that is, through the operation panel to change the output freque</p><p>　　The first scene in general is used for manual adjustment

4、 and parameter settings,The latter two kinds of methods are mostly used for automatic regulation and remote control. Commonly PLC, DCS and other control systems in industrial area are applicable to the conditions of inv

5、erter interface control module,which can facilitate the realization of the closed-loop converter automatic control.They are more commonly used in large and medium-sized control systems. For some small experimental device

6、 and</p><p>　　Using single-chip control inverter can choose the last two kinds of methods.The advantage of the use of communication control full control function. By the appropriate level-shifting inverter c

7、ircuit suitable for the form of communication ,then it can communicate with the inverter.The hardware is simple. The connection between them facilitate a small number of connections. The disadvantage is the need to under

8、stand the communication protocol converter in order to control the programming,and the </p><p>　　The most commonly used method of analog input speed is through potentiometer to adjust the frequency.That is,

9、to change the analog input voltage value to achieve the purpose of speed regulation.Although the use of a mechanical potentiometer is simple, but easy to wear and has no enough long-term stability.Besides there is one of

10、 the greatest shortcomings is that it is only suitable for manual adjustment. Automatic adjustment can not be achieved.Digital Potentiometers used to replace mechanical p</p><p>　　Single-chip components</

11、p><p>　　In addition to operation, single-chip also need complete control. Therefore, counting and timing can not be separated. As a result, single-chip is setted with the counter and timer settings. So far here

12、, we already know the basic components of single-chip, that is, single-chip is setted by the CPU, read-only memory, read-write memory, input / output components and so on. In fact there is also a single-chip clock circui

13、t, which during the operation and control of single-chip can be carried out rh</p><p>　　Single-chip instruction set and assembly language program</p><p>　　Single-chip microcomputer has been desc

14、ribed in front of the main component,these parts constitute single-chip hardware. The so-called hardware, is to see, can be touched and received. However, having such a hardware only means having the possibility of the r

15、ealization of the calculation and control. Truly single-chip microcomputer to calculate and control can also be co-ordination of software. Software refers to various procedures. Only the correct procedure would be deposi

16、ted in a variety of s</p><p>　　When use the single-chip, the prior that should be the problem to be solved is a series of commands. These instructions must be selected to identify and implement single-chip i

17、nstructions. Single-chip customers to solve their own problems by the instructions, known as the source, for the procedure. Opcode instructions are usually divided into two major parts ,which are operation of the compute

18、r and operand.Operation of the computer code means the implementation of any operation, that is, the fun</p><p>　　MCS-51 single-chip has 8-bit word length.Sometimes, it can not fully complete a certain opera

19、tion using only one expressed bytes. Therefore, there is not only single-byte instruction, but also a number of byte instructions in the instruction. By a series of binary 0 and 1 components, there is no obvious characte

20、ristics, poor memory, difficult to understand and easy to make mistakes. Therefore, the direct use of it is very difficult to write procedures. Thus, people use some Mnemonic – usually t</p><p>　　The CPU of

21、 8051 single-chip is made of the controller and the composition operator.</p><p>　　Calculator</p><p>　　Calculator completes the binary arithmetic / logic operations as the core components.Togeth

22、er with registers, accumulator, register, the program marks the state of processor registers and Boolean. Accumulator is a mark of eight registers, which is the most frequently working CPU register. In arithmetic and log

23、ic operations, the accumulator is often temporary in a pre-computing operands, and computing and then save the results. Register is primarily for multiplication and division operations. Reg</p><p>　　Controll

24、er</p><p>　　Controller is the nerve center of the CPU, which includes the timing control logic circuit, an instruction register, decoder, address pointer and program counter, stack pointer and so on. Here th

25、e program counter is of a mark of sixteen registers. To make the single-chip operate implementation of a program, it is necessary to advance the program into an area of memory. Single-chip action should be taken out of a

26、 sequence of instructions to be implemented. Therefore, there must be a circuit to fi</p><p><b>　　Memory</b></p><p>　　Memory is another important component of memory storage of singl

27、e-chip. In each memory cell can be located an eight binary information.It is usually presented with two 16-band information,and this is the contents of memory. Memory of the memory cell address and the contents of memor

28、y cells are different from the two concepts. They can not be confused.</p><p>　　變頻器和單片機的基本知識</p><p>　　變頻調速作為交流電機調速的主要手段已經(jīng)在工業(yè)領域中應用的十分廣泛，其具有的調速范圍寬、穩(wěn)速精度高、動態(tài)響應快、適用范圍廣、運行可靠等技術性能，已逐步取代直流電機調速系統(tǒng)。變頻器的控制方

29、式主要有三種：1.通過變頻器面板操作，即通過操作面板改變頻率的輸出和其他運行參數(shù);2.在變頻器模擬量輸入端輸入0～10V或4～20mA信號,通過改變輸入模擬量的大小控制變頻器的輸出頻率;3.通過變頻器的通訊口進行控制。</p><p>　　第一種方式一般用于現(xiàn)場手動調節(jié)和參數(shù)設定，后二種方式多用于自動調節(jié)和遠程控制。工控領域中常用的PLC、DCS等控制系統(tǒng)都具有適用于變頻器接口條件的控制模塊，可以方便的實現(xiàn)變頻器

30、的閉環(huán)自動控制，在大中型的控制系統(tǒng)中使用較為普遍。而對于一些小型實驗裝置和嵌入式控制裝置，處理器在控制變頻器之外，一般還需要處理鍵盤輸入、顯示屏、數(shù)據(jù)采集和其它過程控制等工作，這種控制要求更適合采用單片機系統(tǒng)作為控制核心，而以PLC加操作面板的形式，雖能實現(xiàn)功能但成本過高，不宜采用。 使用單片機控制變頻器可以選擇后二種方式，采用通訊口方式控制，其優(yōu)點是控制功能全面，通過相應的電平轉換電路適合變頻器的通訊口形式，就可與變頻器進行

31、通訊，硬件簡單，二者間的連線數(shù)量少連接方便。缺點是需要了解掌握變頻器的通訊協(xié)議才能進行控制編程，軟件設計復雜。由于不同品牌的變頻器通訊接口和通訊協(xié)議各不相同，目前尚沒有統(tǒng)一的標準，只能針對一種變頻器進行開發(fā)，縮小了變頻器品種的選擇范圍，適用性受到限制。而對于模擬量輸入控制方式，則幾乎在所有的變頻器中都能支持，雖然在功能上比較單一，但可實現(xiàn)調速的主要功能，能滿足多數(shù)場合的使用要求，具</p><p><b&g

32、t;　　單片機的組成 </b></p><p>　　單片機除了進行運算外，還要完成控制功能。所以離不開計數(shù)和定時。因此，在單片機中就設置有定時器兼計數(shù)器。到這里為止，我們已經(jīng)知道了單片機的基本組成，即單片機是由中央處理器，只讀存貯器、讀寫存貯器、輸入/輸出口等等組成。實際上單片機里面還有一個時鐘電路，使單片機在進行運算和控制時，都能有節(jié)奏地進行。另外，還有所謂的“中斷系統(tǒng)，這個系統(tǒng)有“傳達室”的作用，

33、當單片機控制對象的參數(shù)到達某個需要加以干預的狀態(tài)時，就可經(jīng)此傳達室”通報給CPU，使CPU根據(jù)外部事態(tài)的輕重緩急來采取適當?shù)膽洞胧?lt;/p><p>　　單片機指令系統(tǒng)與匯編語言程序</p><p>　　前面已經(jīng)講述了單片機的幾個主要組成部分，這些部分構成了單片機的硬件。所謂硬件，就是看得到，摸得到的實體。但是，光有這樣的硬件，還只是有了實現(xiàn)計算和控制功能的可能性。單片機要真正地能進行計

34、算和控制，還必須有軟件的配合。軟件主要指的是各種程序。只有將各種正確的程序存入單片機，它才能有效地工作。單片機所以能自動地進行運算和控制，正是由于人把實現(xiàn)計算和控制的步驟一步步地用命令的形式，即一條條指令預先存入到存貯器中，單片機在CPU的控制下，將指令一條條地取出來，并加以翻譯和執(zhí)行。所有這些取數(shù)、送數(shù)、相加、存數(shù)等等都是一種操作，我們把要求計算機執(zhí)行的各種操作用命令的形式寫下來，這就是指令。但是怎樣才能辨別和執(zhí)行這些操作呢？這是在設

35、計單片機時由設計人員賦予它的指令系統(tǒng)所決定的。一條指令，對應著一種基本操作；單片機所能執(zhí)行的全部指令，就是該單片機的指令系統(tǒng)，不同種類的單片機，其指令系統(tǒng)亦不同。</p><p>　　使用單片機時，事先應當把要解決的問題編成一系列指令。這些指令必須是選定的單片機能識別和執(zhí)行的指令。單片機用戶為解決自己的問題所編的指令程序，稱為源程序。指令通常分為操作碼和操作數(shù)兩大部分。操作碼表示計算機執(zhí)行什么操作，即指令的功能；

36、操作數(shù)表示參加操作的數(shù)或操作數(shù)所在的地址。因為單片機是一種可編程器件，只認得二進碼。要單片機運作，單片機系統(tǒng)中的所有指令，都必須以二進制編碼的形式來表示.</p><p>　　MCS－51單片機的字長為8位，有時，要完成某些操作用一個字節(jié)尚不能充分表達。所以，在指令系統(tǒng)中有單字節(jié)指令，也有多字節(jié)指令。機器碼是由一連串的0和1組成，沒有明顯的特征，不好記憶，不易理解，易出錯。所以，直接用它來編寫程序十分困難。因而，

37、人們就用一些助記符——通常是指令功能的英文縮寫來代替操作碼。這樣，每條指令有明顯的動作特征，易于記憶和理解，也不容易出錯。用助記符來編寫的程序稱為匯編語言程序。但是，助記符編寫的程序便于人理解，可單片機卻只認識二進制機器代碼，因此，為了讓單片機能“讀懂”匯編語言程序必須再轉換成由二進制機器碼構成的程序，這種轉換過程，就稱為匯編。匯編可借助于人工查表法來實現(xiàn)，也可借助PC機通過所謂“交叉匯編程序”來完成。由機器碼構成的用戶程序一旦進入了單

38、片機，再啟動單片機，就可讓它執(zhí)行輸入程序所規(guī)定的任務。</p><p>　　單片機8051的CPU由運算器和控制器組成。</p><p>　　運算器　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　</p><p>　　運算器以完成二進制的算術/邏輯運算部件為核心，再加上暫存器、累加器、寄存器、程序狀態(tài)標志寄存器及布爾處理器。累加器是一個八位寄存器，

39、它是CPU中工作最頻繁的寄存器。在進行算術、邏輯運算時，累加器往往在運算前暫存一個操作數(shù)，而運算后又保存其結果。寄存器主要用于乘法和除法操作。標志寄存器也是一個八位寄存器，用來存放運算結果的一些特征，如有無進位、借位等。</p><p><b>　　控制器</b></p><p>　　控制器是CPU的神經(jīng)中樞，它包括定時控制邏輯電路、指令寄存器、譯碼器、地址指針及程序

40、計數(shù)器、堆棧指針等。這里程序計數(shù)器是由16位寄存器構成的計數(shù)器。要單片機執(zhí)行一個程序，就必須把該程序按順序預先裝入存儲器的某個區(qū)域。單片機動作時應按順序一條條取出指令來加以執(zhí)行。因此，必須有一個電路能找出指令所在的單元地址，該電路就是程序計數(shù)器。當單片機開始執(zhí)行程序時，給程序計數(shù)器裝入第一條指令所在地址，它每取出一條指令，程序計數(shù)器的內(nèi)容就自動加1，以指向下一條指令的地址，使指令能順序執(zhí)行。只有當程序遇到轉移指令、子程序調用指令，或遇到

41、中斷時，程序計數(shù)器才轉到所需要的地方去。8051 CPU指定的地址，從存儲器相應單元中取出指令字節(jié)放在指令寄存器中寄存，然后，指令寄存器中的指令代碼被譯碼器譯成各種形式的控制信號，這些信號與單片機時鐘振蕩器產(chǎn)生的時鐘脈沖在定時與控制電路中相結合，形成按一定時間節(jié)拍變化的電平和時鐘，即所謂控制信息，在CPU內(nèi)部協(xié)調寄存器之間的數(shù)據(jù)傳輸、運算等操作。</p><p><b>　　存儲器</b>&