The hottest virtual instrument technology has beco

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Virtual instrument technology has become the mainstream technology in the testing industry Abstract: This paper discusses the key factors that determine the success of virtual instrument technology and its development prospects

key words: virtual instrument; Testing; Test system; Software

vi tech increased by 58.3% year-on-year, nology has been main technology in test field

(National Instruments Co., China branch, Shanghai 200437, China)

abstract: keys of VI technology success and its development pros inspect were discussed in this paper

Key words: VI; measurement; test system; Software

nowadays, the use of virtual instrument technology in testing applications has become the mainstream. Most testing industries have accepted the concept of virtual instrument technology, or tend to adopt virtual instrument technology. For example, although the representative U.S. military is not a leader in technology trends, it is also widely using virtual instrument technology. As the largest independent user of ATE (automated test equipment) in the world, the U.S. Department of defense has adopted the concept of software based instruments in the comprehensive instruments they promote. At present, thousands of large companies have begun to use virtual instrument technology. Only in production testing, industry leaders such as Lexmark, Motorola, Delphi, abb and Phillips have used the hardware and software of virtual instrument technology in key projects and large-scale product testing applications. In the industrial field, virtual instrument technology has been used in automation, oil drilling and refining, machine control in production, and even the control of nuclear reactors

1 innovator's problem

in the field of testing and measurement, traditional instruments improve the performance of measurement by using the existing architecture and continue to innovate in this direction. In the early stage of virtual instrument technology, because its measurement performance is relatively low, it did not bring much threat to traditional instrument manufacturers, so they largely ignored the existence of virtual instrument technology. However, in the late 1980s and early 1990s, virtual instrument technology began to be applied to the measurement that needed flexibility, and these applications could not be achieved by traditional methods. In the late 1990s and the 21st century, with the further improvement of the performance and accuracy of PC processors and commercial semiconductors, the measurement performance of virtual instrument technology has been much improved. Now, virtual instrument technology can match or even exceed the measurement performance of traditional instruments, and it also has higher data transmission rate, flexibility, scalability and lower system cost

Agilent, the leader in the testing and measurement industry, has begun to adopt the concept of virtual instrument technology. For example, Agilent's recent products include a set of "comprehensive instruments" based on Ethernet and arbitrary waveform generators that are compatible with PXI, which is an industry standard virtual instrument technology platform. Recently, John Stratton of Agilent also expressed support for the concept of comprehensive instruments defined by software: "compared with the current standard rack solution, another solution is to use comprehensive instruments. Comprehensive instruments use software algorithms and hardware modules to replace separate test units." At the recent investor conference, Bill Sullivan, Agilent's chief operating officer, proposed that "turning to the use of modular instruments based on software configuration can make users easily reconfigure and reuse, which will be the future development direction of testing and measurement"

2 the key to the success of virtual instrument technology

virtual instrument technology provides a new way to establish a test system, which affects the traditional instrument market. The key to the success of virtual instrument technology is to use the rapidly developing PC architecture, improve the technical ability of engineers, reduce costs, adopt high-performance semiconductor data converters, and introduce system design software, which enables users to build virtual instrument technology systems

2.1pc performance continues to be innovated and reduced. The measurement range is 2 ⑴ 00% lower cost

in the past two decades, the performance of PC has been improved 10000 times, and no other commercial technology has ever had such a high performance growth. Because virtual instrument technology uses PC processor for measurement and analysis, with the emergence of a new generation of PC processor, the use of virtual instrument technology can achieve new applications. For example, current 3GHz PCs can be used for complex frequency domain and modulation analysis for communication test applications unless necessary. Using the 1990 PC (Intel 386/16), the FFT (basic measurement for spectrum analysis) of 65000 points requires 1100s. Now, it only needs about 0 to use a 3.4GHz P4 computer to realize the same FFT 8s。 At the same time, hard disk, display and bus bandwidth have similar performance improvements. The new generation of high-speed PC bus PCI Express can provide a bandwidth of up to 3.2gbytes/s, so you can use PC architecture to achieve ultra-high bandwidth measurement. Some manufacturers claim that the high-speed internal bus will give way to external buses such as yitaihe USB. There is no doubt that these external buses are suitable for some specific application requirements (such as Ethernet is suitable for distributed systems, and USB is easy to connect to the desktop). However, they also have high-speed data transmission rate requirements. For example, a 100ms/s 14 bit if digitizer can generate 200mb/s data, which will be higher than the 80mb/s bandwidth of Gigabit Ethernet. For this reason, you won't see any Ethernet video cards on the market; Even Gigabit networks are 30 times slower than PCI Express. In fact, Gigabit Ethernet interfaces and other peripherals are connected to the CPU through PCI Express. The software based method of virtual instrument technology can abstract the bus in the application software, so as to make use of all these buses - PCI, PCI Express, USB and Ethernet. Many traditional instrument manufacturers solve this problem by embedding PC in the instrument. These instruments usually have an embedded instrument processor and a standard PC motherboard connected to the instrument box through an internal bus. However, this approach has lost two key advantages of PC technology - one is the economies of scale of desktop PC manufacturers like Dell, and the other is the ability to easily upgrade PCs to significantly improve measurement performance. In addition, as shown in Figure 1, the functions of these devices are defined by the manufacturer, and users cannot use the firmware in the device to customize the measurement functions

2.2 enable engineers and researchers to obtain more technical talents

technical talents have become the basic ability of individuals based on society. Generally speaking, our professional technology and computer knowledge were first acquired in school. Recently, in a survey conducted by lason Tai of Vanderbilt University, students agreed with the conclusion that "compared with traditional desktop instruments, computer-based instruments are more friendly and easier to use." The sample number is n=77 students (rating: 1= extremely disagree; 2= disagree; 3= partially agree; 4= agree; 5= extremely agree), and the average answer of students is 4.05. In general, using computer-based virtual instrument technology can get more technical knowledge and programming skills

2.3 continuously improving commercialized a/d and d/a converters

another driving force for the development of virtual instrument technology is the emergence of high-performance, low-cost a/d and d/a converters. Mobile and digital audio applications continue to promote the development of these technologies. Virtual instrument technology hardware can use mass-produced chips as front-end components of measurement. These commercial technologies have developed in accordance with Moore's law - twice the performance every 18 months - while dedicated converter technology has developed very slowly. Commercial semiconductor technology ensures the rapid improvement of the digitalization ability of virtual instrument technology

2.4 graphical system

system design software also promotes the development of virtual instrument technology. In the traditional framework, experts are needed to develop closed instrument functions and algorithms; For virtual instrument technology, the algorithm is open to users, and users can define their own instruments. LabVIEW is such software. LabVIEW adopts graphical data flow language, which can provide engineers and researchers with a very familiar interface - program block diagram. LabVIEW works like a spreadsheet for financial analysis - it allows every computer user to build a powerful financial model. The environment provided by LabVIEW enables all engineers and researchers to become measurement system design experts

3 prospect of system design with virtual instrument technology

virtual instrument technology continues to expand its functions and application scope. Now LabVIEW can not only develop test programs on PC, but also design hardware on embedded processor and FPGA (field programmable gate array). This technology will eventually provide such an independent environment, enabling users to design and test systems to define the functions of hardware, as shown in Figure 2. Test engineers will be able to use appropriate functions for system level design. When they need to define a special measurement function, they can use the same software tools to "refine" the self-healing material is a new material that can automatically repair when an object is cracked or damaged to an appropriate level to define the measurement function. For example, LabVIEW programs can be developed to use modular instruments for certain measurements, such as DC voltage and rise time. When special measurements need to be developed, they can also use LabVIEW to analyze the original measurement data, so as to develop special measurements, such as peak detection. In some cases, if they need to use some new hardware functions to realize measurement, such as customized trigger, they can define a trigger and filter scheme with LabVIEW and embed it into the FPGA on the instrument card

the function and performance of virtual instrument technology have been continuously improved, and now it has become the main alternative to traditional instruments in many applications. With the further updating of PC, semiconductor and software functions, the development of virtual instrument technology in the future will provide an excellent mode for the design of test system, and enable engineers to obtain unparalleled powerful functions and flexibility in measurement and control. (end)

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