本科毕业设计(论文)外文翻译-每个人的LabVIEW.doc

本科毕业设计(论文)外文翻译 译文：准确的说，什么是LabVIEW，它又能为我做什么呢？每个人的LabVIEWLabVIEW是Laboratory Virtual Instrument Engineering Workbench的英文缩写，它是一种图形化的编程环境，使用图形化的符号来创建程序（通过连线把函数节点连接起来，数据就是在这些连线上流动的）；在这点上，它不同于传统的文本编程语言像C,C+，或者Java。然而，LabVIEW不仅仅是一种编程语言，它是专门为那些工作中需要大量编程的工作的工程师和科学家们设计的一种交互式程序开发和执行的系统。LabVIEW开发环境可以工作在装有windows,mac os x,或linu任何一种操作系统的计算机上。LabVIEW创建的程序可以在上述平台上运行，同时也可以运行于microsoft pocket pc,mocrosoft windows ce,palm os和大量的嵌入式平台，包括现场可编程门阵列（FPGAs），数字信号处理器（DSPs）和微处理器。许多使用功能强大的图形化编程语言LabVIEW的用户亲切的称之为“G”语言（取自graphical），LabVIEW能够让你的开发效率提高几个数量级。使用传统语言可能需要几周或者几个月才能完成的程序，如果用LabVIEW编写，几个小时就能完成，其中一个原因是LabVIEW是专为用户设计的，用来进行测量，分析数据和显示结果。另一个原因是LabVIEW有丰富的图形化用户接口（GUI），使用这些接口使变成变得很容易。它也非常适合用来进行仿真，表述思想，编写一般程序，或者讲述基本编程概念。LabVIEW可以提供比标准的实验室仪器更加灵活的仪器，因为这种仪器是基于软件的，是由你来定义仪器的功能，而不是由仪器制造来定义。为了完成你的任务，一个完整的虚拟仪器配置包括：你的电脑，即插即用的硬件和LabVIEW。使用LabVIEW你能够准确的创建你所需要的虚拟仪器，这种仪器的价格是传统仪器价格的几分之一。当你的需求发生改变，你可以随时修改你的虚拟仪器。LabVIEW试图让你的生活变得尽可能的简单，LabVIEW里拥有大量的函数库和子例程，对你的大部分编程任务都是有帮助，同时避免了传统语言中忙乱的指针，内存分配和其他神秘的编程问题。LabVIEW也有专用的代码库，用于数据采集（DAQ），通用接口总线（GPIB）和串口仪器的控制，数据分析，数据显示，数据存储和互联网之间的通信。分析库包括许多有用的函数，有信号产生，信号处理。滤波，加窗，统计，回归，线性代数和矩阵运算。由于LabVIEW图形化的特性，它天生就是一个数据显示程序包。以你所期望的任何形式输出（数据）。趋势图、图表和用户定义的图形正好构成了一小部分有用的可选择的输出（类型）。这本书将向你展示如何显示所有的这些类型的数据。LabVIEW程序在平台之间是可移植的，因此，你可以在macintosh操作系统平台上写程序，然后在一个装有windows操作系统的机子上加载并运行程序，而且在大多数的应用程序中没有改变任何东西。你将会发现LabVIEW在许多的工业应用中提高了运行效率，从各种过程控制到生物，农业，心理学，化学，物理，教学和其他的许多方面。数据流和图形化编程语言LabVIEW编程开发环境不同于标准的C或Java开发系统，其中一个很重要的方面就是：当用其他的基于文本的编程语言去写一行行代码时，LabVIEW用图形化编程语言，通常称为G语言，以图形化形式去编写程序，即所谓的框图。图形化编程消除了许多文本语言中才有的语法细节，例如在哪里该用分号和哪里该用大括号（如果你不知道文本语言是如何使用这些的，不必担心，使用LabVIEW，你不需要知道这些）图形化编程允许你只关注你应用程序中的数据流向，因为它简单的语法并不影响程序正在做什么。LabVIEW使用科学家和工程师熟悉的专业术语，图标和思想。它依赖于图形化的符号去定义程序的行为而不是依赖于文本语言。它执行时是基于数据流原则，所谓的数据流原则就是程序只有在所有的数据都到时才开始执行。由于这些特征，即使你只有些许的编程经验都没有，你能够学习LabVIEW。但是，你将发现编程的基础知识是很有用的。LabVIEW如何工作？ 一个LabVIEW程序由一个或多个虚拟仪器（VIs）组成。之所以叫做虚拟仪器是因为他们的外形和操作通常是模仿真实的物理仪器。但是在后台，他们类似于传统编程语言像C或者Basic中的主程序，函数和子程序。以下，我们将提到的“VI”（发作“vee eye”，不是罗马字母中的六，因为我们听到过有人读作六）指的就是LabVIEW程序。另外，注意：不论一个LabVIEW程序的外形和功能是否和一个真实的仪器有关，我们都把它称为一个VI。一个VI有三个部分：前面板、图框和图表。前面板是一个VI的交互用户接口，之所以会这样命名是因为它模拟物理仪器的前面板。前面板可以包括旋钮、按钮、图形和许多其他的控件（用户输入）以及指示器（程序的输出）。你可以使用鼠标和键盘输入数据，然后在屏幕上看到自己编写的程序显示出结果。 框图是VI的源代码，由LabVIEW图形化语言，即G语言构成。框图是真正的可执行程序，框图程序中的组件由第一级的VIs内建函数，常量和可执行程序控制结构组成。你可以把合适的对象通过连线连接在一起来定义他们之间的数据流向。前面板对象在框图上有相对应的终端，因此数据就可以在用户和后台框图程序之间流动。 为了把在另一个VI中的VI作为一个子程序使用，这个VI必须有定义了连接器的图标。在另一个VI中使用的VI称为子VI，类似与子程序。图标是子VI的图形化表示，在另一个VI的框图程序中作为一个对象使用。一个VI的连接器相当于一个机械装置，用来将数据导入作为另一个VI的子VI。这个连接器定义了这个VI的输入和输出。 虚拟器是分层次，模块化的。你可以把他们作为顶层的程序或者子程序。使用这种结构，LabVIEW突出了模块化编程的概念。首先，你把应用程序分成一系列子程序，接下来，你分别创建一个VI去完成每个子任务，然后把这些VI组合成一个顶层的框图以完成一个更大的任务。 模块化编程是加法运算因为你能够独立的执行每一个子VI，因此有利于调试。此外，很多低级的子VIs通常完成几个应用程序中都有的任务，那么它就被每个独立的应用程序调用。 如果你在使用C+或Java之前就已经用过面向对象，那么你应该知道最简化版的LabVIEW和G不是真正的面向对象语言。但是，面向对象语言有很多的优点，那也就是为什么有几个可以让你在G语言中编写面向对象的代码的工具包，就是通常所说的GOOP（G Object-Oriented Programming）。 虚拟仪器技术是现代实验室的基础。一个虚拟仪器包括计算机，软件和模块化的硬件等；对这些元素进行组合和配置而可以仿效传统的硬件仪器。这就是我们称之为的LabVIEW程序，因为这些功能是由用户自己通过软件定义的，虚拟仪器因而非常灵活，功能强大，并且成本效益高。本章将阐述如何使用LabVIEW与外面的世界进行通信交流（例如，进行一次测量，与一个仪器对话，发送数据给另一台计算机）。 虽然LabVIEW是一个强大的仿真工具，而它常常被用于从外部源收集数据，因为它包含着许多特别针对改目的而创建的子程序（VIs）。例如，LabVIEW能够命令插入式的数据采集设备去获得或产生模拟或数字信号。你也可以使用DAQ设备和LabVIEW去检测一个温度，发送信号到一个外部系统，或测定一个未知信号的频率。LabVIEW也能够使用通用目的的总线接口便利地传输数据，或是串行总线接口。GPIB总线通常被使用于示波器，扫描仪，或万用表的通信，或者远程地驱动一些仪器。LabVIEW软件也能够控制VI硬件仪控系统，以太网，或基于USB接口的仪器。一旦你已经获得或接收到数据，你就能够使用LabVIEW的许多分析功能子程序来加工与处理这些数据。 你将会发现LabVIEW与其它的应用程序或计算机共享数据是非常有用的。LabVIEW有内置的功能用来简化这个过程，它可以支持几种网络协议，从外部地调用现存的代码或动态链接库，或者进行ActiveX的操作。 LabVIEW可以控制DAQ装置读模拟信号（A/D转换），产生模拟输出信号（D/A转换），读写数字信号，操纵车载计数器来进行频率测量，脉冲发生，正交编码测量等，用传感器来接口。在模拟输入的情况下，从传感器来的电压数据进入电脑中的DAQ装置的插件程序中，将数据送入电脑内存进行存储，处理或者其他操作。 Times New Roman小二号，加粗，段前段后均为0.5行原文：What Exactly Is LabVIEW, and What Can It Do for Me?原文来源，Times New Roman小四号labview for evetyoneLabview short for Laboratory Virtual Instrument Engineering Workbench, is a programming environment in which you create programs using a graphical notation (connecting functional nodes via wires through which data flows); in this regard, it differs from traditional programming languages like C, C+, or Java, in which you program with text. However, LabVIEW is much more than a programming language. It is an interactive program development and execution system designed for people, like scientists and engineers, who need to program as part of their jobs. The LabVIEW development environment works on computers running Windows, Mac OS X, or Linux. LabVIEW can create programs that run on those platforms, as well as Microsoft Pocket PC, Microsoft Windows CE, Palm OS, and a variety of embedded platforms, including Field Programmable Gate Arrays (FPGAs), Digital Signal Processors (DSPs), and microprocessors.Using the very powerful graphical programming language that many LabVIEW users affectionately call G (for graphical), LabVIEW can increase your productivity by orders of magnitude. Programs that take weeks or months to write using conventional programming languages can be completed in hours using LabVIEW because it is specifically designed to take measurements, analyze data, and present results to the user. And because LabVIEW has such a versatile graphical user interface and is so easy to program with, it is also ideal for simulations, presentation of ideas, general programming, or even teaching basic programming concepts.LabVIEW offers more flexibility than standard laboratory instruments because it is software-based. You, not the instrument manufacturer, define instrument functionality. Your computer, plug-in hardware, and LabVIEW comprise a completely configurable virtual instrument to accomplish your tasks. Using LabVIEW, you can create exactly the type of virtual instrument you need, when you need it, at a fraction of the cost of traditional instruments. When your needs change, you can modify your virtual instrument in moments.LabVIEW tries to make your life as hassle-free as possible. It has extensive libraries of functions and subroutines to help you with most programming tasks, without the fuss of pointers, memory allocation, and other arcane programming problems found in conventional programming languages. LabVIEW also contains application-specific libraries of code for data acquisition (DAQ), General Purpose Interface Bus (GPIB), and serial instrument control, data analysis, data presentation, data storage, and communication over the Internet. The Analysis Library contains a multitude of useful functions, including signal generation, signal processing, filters, windows, statistics, regression, linear algebra, and array arithmetic.Because of LabVIEWs graphical nature, it is inherently a data presentation package. Output appears in any form you desire. Charts, graphs, and user-defined graphics comprise just a fraction of available output options. This book will show you how to present data in all of these forms.LabVIEWs programs are portable across platforms, so you can write a program on a Macintosh and then load and run it on a Windows machine without changing a thing in most applications. You will find LabVIEW applications improving operations in any number of industries, from every kind of engineering and process control to biology, farming, psychology, chemistry, physics, teaching, and many others.Dataflow and the Graphical Programming LanguageThe LabVIEW program development environment is different from standard C or Java development systems in one important respect: While other programming systems use text-based languages to create lines of code, LabVIEW uses a graphical programming language, often called G, to create programs in a pictorial form called a block diagram.Graphical programming eliminates a lot of the syntactical details associated with text-based languages, such as where to put your semicolons and curly braces. (If you dont know how text-based languages use these, dont worry. With LabVIEW, you dont need to know!)Graphical programming allows you to concentrate on the flow of data within your application, because its simple syntax doesnt obscure what the program is doing. LabVIEW uses terminology, icons, and ideas familiar to scientists and engineers. It relies on graphical symbols rather than textual language to define a programs actions. Its execution is based on the principle of dataflow, in which functions execute only after receiving the necessary data. Because of these features, you can learn LabVIEW even if you have little or no programming experience. However, you will find that a knowledge of programming fundamentals is very helpful.How Does LabVIEW Work?A LabVIEW program consists of one or more virtual instruments (VIs). Virtual instruments are called such because their appearance and operation often imitate actual physical instruments. However, behind the scenes, they are analogous to main programs, functions, and subroutines from popular programming languages like C or Basic. Hereafter, we will refer to a LabVIEW program as a VI (pronounced vee eye, NOT the Roman numeral six, as weve heard some people say). Also, be aware that a LabVIEW program is always called a VI, whether its appearance or function relates to an actual instrument or not.A VI has three main parts: a front panel, a block diagram, and an icon.The front panel is the interactive user interface of a VI, so named because it simulates the front panel of a physical instrument (see Figure 1.4). The front panel can contain knobs, push buttons, graphs, and many other controls (which are user inputs) and indicators (which are program outputs). You can input data using a mouse and keyboard, and then view the results produced by your program on the screen.The block diagram is the VIs source code, constructed in LabVIEWs graphical programming language, G (see Figure 1.5). The block diagram is the actual executable program. The components of a block diagram are lower-level VIs, built-in functions, constants, and program execution control structures. You draw wires to connect the appropriate objects together to define the flow of data between them. Front panel objects have corresponding terminals on the block diagram so data can pass from the user to the program and back to the user.In order to use a VI as a subroutine in the block diagram of another VI, it must have an icon with a connector (see Figure 1.6). A VI that is used within another VI is called a subVI and is analogous to a subroutine. The icon is a VIs pictorial representation and is used as an object in the block diagram of another VI. A VIs connector is the mechanism used to wire data into the VI from other block diagrams when the VI is used as a subVI. Much like parameters of a subroutine, the connector defines the inputs and outputs of the VI.Virtual instruments are hierarchical and modular. You can use them as top-level programs or subprograms. With this architecture, LabVIEW promotes the concept of modular programming. First, you divide an application into a series of simple subtasks. Next, you build a VI to accomplish each subtask and then combine those VIs on a top-level block diagram to complete the larger task.Modular programming is a plus because you can execute each subVI by itself, which facilitates debugging. Furthermore, many low-level subVIs often perform tasks common to several applications and can be used independently by each individual application.If youve worked with object-oriented languages before such as C+ or Java, you should know that LabVIEW and G in it simplest form is not truly an object-oriented language. However, object-oriented programming can provide many benefits, which is why there are several toolkits that let you write object-oriented code in G, known as GOOP (G Object-Oriented Programming). For more information on GOOP, see Appendix D, LabVIEW Object-Oriented Programming.Virtual instrumentation is the foundation for the modern laboratory. A virtual instrument consists of a computer, software, and modular hardware; all combined and configured to emulate the function of traditional hardware instrumentation. Its also what we call a LabVIEW program. Because their functionality is software-defined by the user, virtual instruments are extremely flexible, powerful, and cost-effective. This chapter explains how to communicate with the outside world (e.g., take measurements, talk to an instrument, send data to another computer) using LabVIEW. Were only giving you a very brief overview here; you can learn more about acquiring data, controlling instruments, and networking your computer with LabVIEW in the second half of this book. In this chapter, youll also learn a little about how LabVIEW has changed over the years.Although LabVIEW is a very powerful simulation tool, it is most often used to gather data from an external source, and it contains many VIs built especially for this purpose. For example, LabVIEW can command plug-in data acquisition, or DAQ, devices to acquire or generate analog and digital signals. You might use DAQ devices and LabVIEW to monitor a temperature, send signals to an external system, or determine the frequency of