Personal computers have resided on engineers' desktops for decades. But they weren't always the powerful, multifaceted tools that they are today. Once used solely for data processing, e-mail, and other mundane tasks, powerful hardware and sophisticated software have turned the humble PC into a valuable engineering design aid.
Gains in hardware have the PC approaching the performance of Unix workstations. A typical PC today can execute over 3 billion instructions per second, store more than 500 Gbytes of data, and create images with extremely high resolutions. And the advent of 64-bit PC processors has further blurred the line between PCs and workstations.
While the hardware is quite impressive, PCs can't do much without the application software that transforms these machines into flexible engineering tools. The existing cornucopia of PC engineering software enables users to perform tasks ranging from complex calculations, analysis, and visualization to programmable test and measurement functions. In addition, PC-based EDA software helps engineers create chips, boards, and systems at a fraction of the cost of its Unix counterparts.
FUNCTIONAL FLEXIBILITY
Yesterday's rudimentary PC-based tools have matured into today's flexible applications, allowing the PC to better meet users' changing needs. A popular application for the desktop PC is virtual instrumentation. A virtual instrument consists of an industry-standard PC equipped with application software, plug-in boards, and driver software, which together perform the functions of traditional instruments. Virtual instruments are software-centered systems that exploit the computing power, productivity, display, and connectivity capabilities of desktop computers.
PCs have all of the important components of a benchtop tool—display, processor, I/O, and software. But a benchtop instrument has fixed functionality. With virtual instruments, engineers build measurement and automation systems that perfectly suit their needs, instead of being limited by traditional fixed-function instruments.
One example is the LabView software from National Instruments (www.ni.com). This graphical development environment lets engineers design custom virtual instruments. Engineers create a graphical user interface on the computer screen through which they can operate the instrumentation program, control selected hardware, analyze acquired data, and display results. Users can customize their front panels with knobs, buttons, dials, and graphs to emulate control panels of traditional instruments, create custom test panels, or visually represent the control and operation of processes.
The company breaks down instrument functionality into modular pieces, which are then used to "build" the necessary application. Engineers can use hundreds of functions that are geared toward measurement and control applications. They still need plug-in PC hardware for data acquisition, but the software exploits the PC's programmability.
Software is the most important component of a virtual instrument. With the right software tool, engineers can efficiently create their own applications by designing and integrating the routines required by a particular process. They can also create an appropriate user interface that best suits the purpose of the application and those who will interact with it. Engineers can define how and when the application acquires data from the device; how it processes, manipulates, and stores the data; and the way results are presented to the user.
"The beauty of PC-based instrumentation," explains Jenifer Loy, LabView product manager, "is that as the PC changes, your instrument automatically gets upgraded." National offers a suite of modular products. It has solutions for both desktop PCs and laptops, using a PCMCIA slot for small-form-factor digitizing. The company's goal is to create tools that make engineers more efficient. The laptop's portability is needed because engineers do measurements in all types of locations (see "Bringing Test Out Of The Lab And Into The Field," below).
LabView 7 Express, the latest version of the software, streamlines the development of common measurement tasks by encapsulating functionality in more than 38 interactive virtual instruments (VIs). Users drop an Express VI on the block diagram and use dialog boxes to configure their acquisition, analysis, or presentation function with no programming. The goal was to provide the functionality of the LabView software with a faster, easier to use interface. What would take hours or even days with previous versions of the product can be done in minutes.
Data Translation (www.datatranslation.com) is another supplier of application-building software for test and measurement, control, and analysis using a PC. Although the company has supplied data-acquisition hardware for a long time, it decided several years ago to create its own software applications. Its product, called DT Measure Foundry, is an application-building package that lets users drag and drop control and display objects onto the screen and configure them by defining a list of properties. Users aren't required to wire one object to another, nor do they need to compile anything. For example, they can configure an oscilloscope panel to display a number of input channels from a data source, and then run the application.
Users can export their results to numerous analysis programs, including the Matlab software and Microsoft's popular Excel spreadsheet. The company's latest product for the PC is DT Measure Foundry/RT-Streaming, a software application that streams real-time data from an embedded DSP to a host PC. Full Windows control from the host PC allows a pre-compiled COFF file (DSP file format) to be executed seamlessly.
Tim Ludy, product marketing manager for Data Translation, points out that in recent years the PC has proven its value as an engineering tool. Before that, he explains, these types of applications could be hampered by the PC's limitations. For example, data acquisition could run out of I/O due to the PC's limited number of slots. Today, that's never a problem because the standard USB port can accommodate up to 127 devices.
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