Labviewbased virtual function Signal Generator（基于Labview的虚拟函数信号发生器的设计）外文翻译.doc

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1、Labview-based virtual function Signal Generator1 IntroductionSince 1986, the U.S. NI (National Instrument) companies to the concept of virtual instrumentation, along with computer technology and measurement technology, virtual instrument technology has also been developed rapidly. Virtual instrument

2、 means: use of the existing PC, with a specially designed instrument hardware and proprietary software, the formation of the basic functions of both the ordinary instrument, there are usually no special equipment features of the new instrument. Compared with the traditional instruments of its featur

3、es are: better measurement accuracy and repeatability; measurement speed; system set up time is short; instrument function defined by the user; scalability; technical updates and quick. Virtual instrument software as the core, the software company Youyi U.S. NI Labview virtual instrument software de

4、velopment platform most commonly used. Labview is a graphical programming language, mainly used to develop data acquisition, instrument control and data processing and analysis software, and powerful. Currently, the development of software in the international test, measurement and control industry,

5、 popular, measurement and control areas in the country has also been widely used. Function Generator is a scientific research and engineering design in a widely used general-purpose equipment. The following function signal generator with a virtual design and development of specific description is ba

6、sed on graphical programming language Labview virtual instrument programming and implementation of technology.2 virtual function signal generator structure and composition2.1 Virtual Function Generator front panelThis virtual function signal generator mainly consists of a PCI bus, multi-function dat

7、a acquisition card and appropriate software. Them installed on a PC running Windows95/98/2000/NT the machine, shall constitute a powerful function of signal generator. The design of the virtual function signal generator reference signal generator SG 1645 power functions, front panel shown in Figure

8、1. Figure 1 virtual function signal generator front panelThe function generators front panel function of the following components: instrument control button, the output frequency control window (including the frequency of display units), frequency fold into control, waveform selection, frequency tun

9、ing button, dc bias, square wave accounts for Air ratio adjustment, the output waveform amplitude control buttons. Frequency tuning range: 0.1 1 Hz; DC bias: -10 10V; square wave duty cycle: 0 to 100%; output waveform range: 0 10V. Also increased the number of modification of voltage-controlled comp

10、onents such as panel input count input, synchronous output, voltage output. Modification of the use of these components is intended to increase the aesthetics of the instrument, and as far as possible with real instruments consistent user interface2.2 Virtual Function Signal Generator hardware struc

11、tureThis virtual function signal generator hardware input and output data acquisition card and a certain configuration requirements of the PC, the data input and output depend on input data acquisition card, the definition of output achieved. This design uses the PCI-1200 data acquisition card is a

12、good cost-effective products, with the D / A conversion functions, can generate the digital signals into analog signals and digital-analog converter and high precision, but also has filtering capabilities, which Smooth the output waveform. It supports the unipolar and bipolar analog signal input, th

13、e signal input ranges of -5 +5 V and 0 10V. Provide 16 single-ended / 8 differential analog input channels, 2 independent of the DA output channels, 24-line TTL digital I / O, 3 16-bit timer counters and other features. Some of the hardware interface for data input or output channel settings. Some o

14、f the hardware interface block diagram shown in Figure 2:Figure 23 Virtual Function Signal Generator Design and ImplementationSome use professional LabVIEW6i software virtual instrument graphical development tools. Virtual function signal generator output waveform mainly in software production and t

15、he output signal frequency display. Changes in the frequency of the output waveform is a concrete realization of data acquisition waveform data written to the buffer among the buffers by setting the update frequency (to change the internal clock frequency) to achieve the output data frequency. The p

16、rocess is mainly in the use of Labview data acquisition sub-module of the AO START function modules. Function from the implementation point of view, this design features a virtual function signal generator structure includes two modules: Module waveform generator (FG module) and frequency change con

17、trol unit (DISPLAY) module. Waveform generator module and call FGEN module. FGEN module for the digital waveform generator module. Digital waveform generator module 3.1Waveform generated virtual function signal generator module is the core of the software. The module can be realized using sine, squa

18、re, sawtooth, triangle and other waveforms. Sine wave generation principle is by calling the sin (x) function to implement. In this design, the design of each component sine wave cycle from 1000, using similar language in the For loop C as x assignment, so that the implementation of a For loop, you

19、can generate a cycle of sine wave generating the data needed, and then use While Circulation, make the program repeatedly executed, can be continuously output sine wave. Square wave, sawtooth, triangle and sine wave generation theory produce similar principles are achieved through the mathematical s

20、equence of numbers representative of the waveform. Compared with the analog signal, generated using the software method of digital waveform sequence although there are some errors, but the election cycle as long as a sufficient number of points, you can make errors to a minimum, the least impact on

21、the results. Waveform generated by the software one of the biggest advantage is greatly reduced the cost of the instrument and the instrument of small intelligent. Waveform generator modules front panel shown in Figure 3, waveform generation module block diagram shown in Figure 3Change of 3.2 unit o

22、f frequency control moduleWhen the output frequency dynamic range is large, with a single spin button control, due to a small rotation angle, you will have a greater change in the frequency, to the frequency of accurate Shezhi brought greater Kunnan, and frequency by using a knob Times by combining

23、the output frequency can greatly improve the control accuracy. In order to improve control accuracy of the output frequency, which in this design, by using the unit of frequency change control module, the output control accuracy can be achieved 0.001Hz. The modules front panel shown in, the module b

24、lock diagram shown in Figure 4 .Figure 44 Total Results:As a Labview graphical programming software development and testing system is a powerful, convenient and efficient programming tools. Similarity between the good, open, exclusive, making the test development cycle is short, low cost and high qu

25、ality. Labview-based virtual machine interaction with the function signal generator is good, easy to operate and so on, to a wide range of applications and in scientific research, production and other fields.1 Pan H Z, et al. LabVIEW-based virtual Function Signal GeneratorJ . Control Enginerring Pra

26、ctice,2. Evans P D, Brown D. Simulation of brushless DC drivesc IEE Proceedings B, Electric Power Applications，137(5) : 299-3083. Ren Spe, Alan K. Wallace and Joel Davis. Modeling of brushless dc drive systems with pulse-width modulated excitationJ, Mathematical and Computer Modelling, Volume 11, 19

27、88, Pages 1166-1171.4. Jawad Faiz, M. R. Azizian and M. Aboulghasemian-Azami. Simulation and analysis of brushless DC motor drives using hysteresis, ramp comparison and predictive current control techniquesJ, Simulation Practice and Theory, Volume 3, Issue 6, 15 January 1996, Pages 347-363.5. J. Fig

28、ueroa, C. Brocart, J. Cros and P. Viarouge. Simplified simulation methods for polyphase brushless DC motorsJ. Mathematics and Computers in Simulation, Volume 63, Issues 3-5, 17 November 2003, Pages 209-224.6. J. Shao, D. Nolan, and T. Hopkins. A Novel Direct Back EMF Detection for Sensodess Brushles

29、s DC (BLDC) Motor DrivesC. Applied Power Electronic Conference (APEC 2002), 2002: 33-38.7. Doo-Hee Jung and In-Joong Ha. Low Cost Sensorless Control of Brushless DC Motors Using a Frequency Independent Phase Shifter JIEEE Transactions on power electronic, 2000, 15: 744-752.8. Kuang-Yao Cheng and Yin

30、g -Yu Tzou. Design of a Sensorless Commutation IC for BLDC Motors JIEEE Transactions On power electronic, 2003, 18: 1365-1375.基于Labview的虚拟函数信号发生器的设计1前 言自从1986年美国NI(National Instrument)公司提出虚拟仪器的概念以来,随着计算机技术和测量技术的发展,虚拟仪器技术也得到很快的发展。虚拟仪器是指:利用现有的PC机，加上特殊设计的仪器硬件和专用软件,形成既有普通仪器的基本功能,又有一般仪器所没有的特殊功能的新型仪器。与传统的

31、仪器相比其特点主要有:具有更好的测量精度和可重复性;测量速度快;系统组建时间短;由用户定义仪器功能;可扩展性强;技术更新快等。虚拟仪器以软件为核心,其软件又以美国NI公司的Labview虚拟仪器软件开发平台最为常用。Labview是一种图形化的编程语言,主要用来开发数据采集，仪器控制及数据处理分析等软件,功能强大。目前,该开发软件在国际测试、测控行业比较流行,在国内的测控领域也得到广泛应用。函数信号发生器是在科学研究和工程设计中广泛应用的一种通用仪器。下面结合一个虚拟函数信号发生器设计开发具体介绍基于图形化编程语言Labview的虚拟仪器编程方法与实现技术。2虚拟函数信号发生器的结构与组成2.

32、1虚拟函数信号发生器的前面板本虚拟函数信号发生器主要由一块PCI总线的多功能数据采集卡和相应的软件组成。将它们安装在一台运行Windows95/98/2000/NT 的PC机上，即构成一台功能强大的函数信号发生器。本虚拟函数信号发生器的设计参考了SG 1645功率函数信号发生器，前面板如图1所示。本函数信号发生器的前面板主要由以下几个部分构成：仪器控制按钮，输出频率控制窗口（包括频率显示单位），频率倍成控制，波形选择，频率微调按钮，直流偏置，方波占空比调节，输出波形幅度控制按钮。频率微调范围：0.11 Hz；直流偏置：-1010V；方波占空比：0100%；输出波形幅度：010V。此外还增加了许

33、多修饰性的元件如面板上的压控输入、记数输入、同步输出、电压输出等。使用这些修饰性的元件的目的是为了增加仪器的美观性，并尽量与真实仪器的使用界面相一致2.2虚拟函数信号发生器的硬件构成本虚拟函数信号发生器的输入输出的硬件部分为一数据采集卡和具有一定配置要求的PC机，数据的输入输出靠对数据采集卡输出输入口的定义来实现。本设计采用的PCI-1200数据采集卡是一块性价比较好的产品，具备数/模转换的功能，能将产生的数字信号转换成模拟信号且数模转换精度高，而且还具备滤波功能，从而使输出波形光滑。它支持单极和双极性模拟信号输入，信号输入范围分别为-5+5V和010V。提供16路单端/8路差动模拟输入通道、

34、2路独立的DA输出通道、24线的TTL型数字I/O、3个16位的定时计数器等多种功能。硬件接口部分用于数据输入或输出时的通道设置。硬件接口部分程序框图如图2所示：3虚拟函数信号发生器的软件设计与实现软件部分采用专业的LabVIEW6i图形化虚拟仪器开发工具。虚拟函数信号发生器主要由软件完成输出波形信号的产生和输出信号频率的显示。输出波形频率的变化的具体实现是将波形数据写入数据采集卡的缓冲区当中，通过设置缓冲区的更新频率（改变内部的时钟频率）来实现输出数据频率的变化。该过程主要运用了Labview中的数据采集子模块中的AO START 功能模块。从实现功能的角度来说，本次设计的虚拟函数信号发生器

35、的功能结构主要包括两大功能模块：波形产生模块（FG模块）和频率单位变化控制（DISPLAY）模块。波形产生模块又调用FGEN模块。FGEN模块为数字波形产生模块。3.1数字波形产生模块波形产生模块是虚拟函数信号发生器软件的核心。利用该模块可实现正弦波、方波、锯齿波、三角波等波形。正弦波的产生原理是通过调用sin(x)函数来实现。在本次设计，设计每一正弦波周期由1000点组成，利用类似C语言中的For循环为x 赋值，这样执行一次For循环，便可以产生生成一个周期正弦波所需的数据，然后利用While 循环，使程序反复执行，就可以连续输出正弦波形。方波、锯齿波、三角波的产生原理与正弦波产生原理相近,

36、都是通过数学运算来实现代表波形的数字序列。与模拟信号相比，利用软件的方法产生的波形数字序列虽然存在着一定的误差，但只要一个周期内选的点数足够的多，就可以使误差降到最低，对结果的影响最小。利用软件产生波形的一个最大的优点是使仪器的成本大大降低，而且使仪器小型化，智能化。波形产生模块的前面板如图3所示，波形产生模块的程序框图如图3所示。3.2 频率单位变化控制模块当输出频率动态范围较大时，用单个旋转按钮控制时，由于旋转一个很小的角度就会产生较大的频率变动，给频率的准确设置带来了较大困难，通过使用一个旋钮和频率倍乘相结合，可大大提高频率的输出控制精度。为了提高频率的输出控制精度，在本次的设计当中，通过使用频率单位变化控制模块，使输出控制精度可达到0.001Hz。该模块的前面板如图5所示，该模块的程序框图如图 4所示。4 总 结Labview作为一个图形化编程软件，是开发测试系统的一种功能强大、方便快捷的编程工具。其良好的相通性、开放性、专用性，使测试系统的开发周期短、成本低、质量高。基于Labview的虚拟函数信号发生器具有机交互性好、易于操作等特点，能够广泛的应用与于科研、生产等领域。