外文翻译--基于LabVIEW的虚拟示波器研究和开发

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1、附 录 - 1 - 中文 5650 字 ， 3300 单词 出处： Liu Y, Han Y, Yu S. Research & Development of Virtual Oscillograph Based on LabVIEWC/ IEEE International Conference on Industrial Informatics. 2006:1124-1128. 附 录 Research & Development of Virtual Oscillograph Based on LabVIEW Abstract: This paper introduces the des

2、ign process of a virtual oscillograph based on LabVIEW. Mainly analyzes the amplitude value and time base adjusting methods during the real-time display. At the same time, it simply introduces the basic thought when measuring the period and frequency of the waveform gate voltage method and its appli

3、cation. At the end of this paper, combining the parameter measurement and waveform display of the virtual oscillograph with the modern motor close-loop lock-phase speed control, it analyzes the parameter measurements effect in PID control. Keywords: Virtual Oscillograph； Time-Base； Motion Control .

4、INTRODUCTION In the rapidly developing industry control field, measuring technologies and apparatus become more and more important. But because of the disadvantages of the traditional instruments such as high price, single function, bad expansibility, etc., they can hardly meet the industry requirem

5、ent. With the development of computer technologies and virtual instruments (VI for short), the scope designed by users becomes widely. There are many different functions with the same hardware which can make two or more machines work synchronously with the advanced bus technologies such as PXI bus t

6、echnology 1.Virtual instruments become more and more popular for its upstanding characteristics like low cost, multi-function, facility and so on. All measuring instruments consist of three parts: data acquisition, data analysis and results output 2. In these three parts, data acquisition can be don

7、e by the system hardware like A/D module or digital I/O modules. Data analysis and results output can be completed by software system based on computer. So, if given some necessary data acquisition hardware, a measuring instrument based on computer can be constituted. The software technology is the

8、essential one in the virtual instrument. 3 Visual C+, LabVIEW, LabWindows/CVI, VEE etc. are all development software environment. LabVIEW is a graphic programming language called G language, which can be used in GPIB, VXI, PXI, PCI Bus and data acquisition cards based hardware system, has powerful a

9、nalyzing ability. Its graphic programming method can be used to finish the total program by dataflow clearly and simply. Using its embedded board card driver interface, we can conveniently operate a board card. 4, 5 Multi-channel digital oscillograph, which mainly used in real-time data acquisition,

10、 is one of the most widely used general measuring instruments. It also can display the changes of some electric signals and compare the differences among different signals. So the research and development of virtual oscillograph is the hotspot in the area. Making use of the Graph platte in LabVIEW,

11、you can conveniently acquire the dynamic waveforms and make them displayed. But most virtual oscillographs based on LabVIEW use the Graph platte to operate and analyze the waveform data. Although this is very facile to use, it also has many disadvantages: (1) When the waveform changes all the time,

12、the screen will keep refreshing and the graph platte could not properly work. (2) The operation method cant satisfy most of operators because it is 附 录 - 2 - different from the tradition oscillograph in operation. To solve these problems, this paper brings forward some ways. In the real- time wavefo

13、rm display, we redevelop the waveform operation and introduce some related software arithmetic. It introduces the exploiting thinking of adjusting dynamic time base and put forward two concepts: the FIFO process and E-M process. In addition, it introduces a successful gate-voltage measure way in the

14、 measurement of the period and frequency, and based on which, the paper puts forward the application in the close-loop lock-phase System. II. RESEARCH ON THE MULTICENTER DIGITAL OSCILLOGRAPHS SOFTWARE ARITHMETIC The virtual oscillograph introduced by this paper is mainly used in laboratory for the m

15、easurement and storage of various analog signals. The main functions are: data acquisition, waveform display, parameter measurement, waveform storage and replay etc. It has 64 analog signal input channels and can take 8 signal observations at the same time with the choice of switch matrix. According

16、 to the requirement, we use the NI-6133 Daq card for the data acquisition. The block diagram of virtual oscillograph is shown in Fig. 1: 6 Now we will introduce the soft arithmetic to the basic functions of virtual oscillograph. A. Characteristics of Graph Control In LabVIEW, there are three control

17、s for waveform displaying: Graph, Chat and x-y graph. Every control has its own advantages. This paper takes Graph control for example to discuss the soft arithmetic to the basic function of virtual oscillograph. Graph oscillograph displays all waveform data input in the screen at a time. Every time

18、 when the waveform data are input, the screen will be freshed. 7 Using its own operation tools, you can move, zoom the waveform or use the cursors to measure the parameters. But it could not work well on dynamic waveform. So its necessary to develop a more convenient operation tool to real-time disp

19、lay of dynamic waveform. In the virtual oscillograph introduced in this paper, there are some basic functions such as amplitude and position value adjustment, time base change, trigger mode selection etc. The oscillographs front panel is shown in fig.2. 附 录 - 3 - B. Amplitude Value Adjustment Multi-

20、center oscillograph can display more than one waveform at the same time, so it is very convenient to compare every signal change. Every waveform displayed should be operated separately through the selecting box on the front panel. At first, we distribute the screen into 1010 grids and set every chan

21、nel a Y-axis. The value of every one of the 10 grids in the Y-axis is equal to the value of related amplitude knob control. With the property node of the waveform graph, you can set the minimum value of each Y-axis as -5 times much as the knob value whereas the maximum value set 5 times. So when you

22、 change the amplitude knob value, the minimum and the maximum value of the relevant Y-axis should be changed at the same time, the waveform display can be zoomed as required, and the zero point position is kept in the original location. Use an array to save the amplitude values every Y-axis changed.

23、 When a channel is selected, put its old amplitude value to the knob first； and after adjusting, replace the related array element with the new value. And then the amplitude value change function is finished. C. Time Base Adjustment Time base adjusting is one of the basic functions in oscillograph.

24、The time base adjusting knobs value shows the time of every one grid of X-axis in the screen which is the nodus during the oscillograph design procedure. 1) Basic Clew According to the characteristics of the Graph control, it displays all the data input at a time. So distribute the X- axis into 10 g

25、rids and make every grids time t. If the waveform could bestride the whole X-axis, the time spent to collect all the data is 10t. Suppose the boards sampling rate is f, in other word, the board collects f data every second. So the number N needed in the waveform is: N= fl0t =l0ft （ 1） Keeping the bo

26、ard sampling at the frequency of f, the program reads N data points from the board memory and put them to the oscillograph in every loop. Change the t value is to change the N value read from board memory every time, and thus adjust the time base in the real-time sampling. But through the experiment

27、 we can see, when the time base is too long (100ms) or too short ( 500us), the waveform displayed has time lags to different extend. That is because when the time base is too long (if the length of the needed waveform exceeds 1 second), we must wait for enough time to get all needed data collected by the board, and display them on the screen at a time. So that can cause discontinuous waveform displayed in the screen. When the time base is too short, the N value read every