by Alan S. Brown, Associate Editor
Off the coast of Norway, a huge robotic excavator prepares the seabed for installation of a natural gas pipeline. Halvor Snellingen of France’s Nexans S.A. devised a system to monitor the robot using video and acoustic and other sensors, as well as to control it to within 10 or 20 centimeters even at depths of 1,000 meters. Snellingen used software called LabView to make it work.
The developer of LabView, National Instruments in Austin, Texas, says it wants to bring system control closer to the hands of mechanical engineers and others whose jobs are not to build computer programs, but to use them. It’s part of the virtual instrumentation area, which National Instruments does not occupy alone, but where the company does claim to be the far-and-away leader.
The company says its latest products are part of a push to provide simple tools that let mechanical engineers and other “domain experts” use intuitive software to customize their test and control systems. What’s more, the company says it is giving software a greater role so more functions can be turned over to a common PC that used to require hard-wired instruments.
National Instruments’ new software, LabView Signal Express, is intended to let engineers automate data logging, analysis, and storage. It works with more than 250 plug-in data acquisition devices, and controls more than 400 modular and stand-alone sensors and instruments.
Attach a thermocouple, for instance, and Signal Express instantly recognizes it as a heat sensor. It then provides drop-and-drag graphics and menus that let users decide what data they want to capture and store. Engineers can also use embedded functions to filter and analyze data, or write their own custom routines.
Signal Express now comes standard on CompactDAQ, National Instruments’ modular data acquisition system. CompactDAQ plugs into a PC or laptop USB port and accepts up to eight sensor modules that could monitor anything from temperature and pressure to voltage and acceleration.
Along with its release of Signal Express, National Instruments also introduced 19 new CompactDAQ plug-and-play sensor modules. This brings the company’s array of modules to 30. According to National Instruments, Signal Express can give a computer the functions of a broad range of virtual instruments.
The growing power and simplicity of software-based instruments is part of what National Instruments marketing vice president John Graff calls “Instrumentation 2.0.”" He likens software instrument flexibility to the Macintosh Corp.’s new iPhone, whose touchpad display morphs from a phone to a music player to a text messaging keyboard depending on users’ directions.
The concept is catching on. Ten years ago, software-defined products handled fewer than one-quarter of the sensors managed by hard-wired instruments. Today, according to Graff, they have pulled roughly even. Even companies long associated with stand-alone instruments, such as Tektronix Inc., offer instrument automation software with some of their products.
Behind their growing use is a rapid increase in speed and precision, thanks to improvements in processor and bus speed. Even 10 years ago, the speed and accuracy of analog-to-digital to converters in virtual instruments were far below the standards set by hard-wired equipment. Now they are approaching parity.
In the past, processors were held back by data buses that control the speed at which sensors feed data into a computer. This has changed. The PCI bus introduced in 1993 could handle more than 100 million 8-bit samples per second, fast enough for audio. The three-year-old PCI Express bus boosts that to nearly 10 billion samples per second, fast enough for video. At lower speeds, PC buses achieve resolutions (as measured in bits of data) nearly as good as those of hard-wired instruments.
Software-based instruments have also benefited from faster computer processors. More recently, chipmakers have introduced chips based on two or more computing cores. LabView, National Instruments’ visual programming software, has been able to take advantage of such multicore processors since 2001.
LabView was originally developed to program software-based instruments, but National Instruments believes it can be used to prototype product control systems.
It can also build programs for embedded processors, such as field-programmable gate arrays. The latter are semiconductor processors that use logic capabilities controlled by software rather than wired into the hardware. LabView lets engineers program these devices by dropping and dragging control blocks to form a flow sheet. The back end of the software then builds the actual device program.
According to Graff, Instrumentation 2.0 speeds prototyping and design, and costs less and has greater flexibility than dedicated instruments.
Michael Wiltberger, principal engineer of Santa Clara, Calif.-based OptiMedica Corp., used LabView to build a working prototype of a laser eye surgery unit in only a few months. The unit semiautomates up to 25 patterned laser burns at a time, making it possible for an ophthalmologist to produce up to 2,000 burns in only a few minutes.
Wiltberger plans to build the system using field-programmable gate arrays so the company can reprogram systems to update and customize them.
Yet software-defined instruments also have limitations. They don’t yet have the precision and speed of hard-wired products. While graphic development languages like LabView and VEE from Agilent Technologies Inc. certainly simplify measurement and control, they don’t offer all the bells and whistles of a true programming language. And even though LabView already takes advantage of parallel processing, it has a way to go before it catches up to the latest generation of multicore processors.
Still, if National Instruments’ goal is to put instrumentation and control into the hands of mechanical engineers, it has come a long way in a short time.