"It's What You Know," Feature Article, June 2006

it's what you know

Data acquisition goes well beyond
engineering—just ask a piano maker or an entomologist.

by Jean Thilmany, Associate Editor

data acquisition is a boring name for an interesting application that samples the real world. The method acquires and interprets raw data via monitors that join the object to be studied with a computer programmed to interpret the information. Engineers acquire data to understand how products—say, an automotive engine—operate under real-life conditions.

There are plenty of data ac apps—as those in the know say—culled from the wide world beyond the manufacture of engines. Disparate endeavors turn to data acquisition hardware and software to get the information they need to study and improve performance of all kinds.

A case in point is the glassy-winged sharpshooter. Once barely a blip on California winemakers' radar of potential crop hazards, the half-inch-long bug has quickly morphed into enemy No. 1 within the last several years. The name strikes fear into even the most stout-hearted winemakers.

And this insect's moniker is apt. However inadvertent, the insect pinpoints grape vines and injects them with killer bacteria. By the very act of feeding, the sharpshooter deposits bacteria, which soon prevent the flow of water and nutrients through plant vessels, according to Elaine Backus, a research entomologist with the U.S. Department of Agriculture.

The bacteria had been in California for more than 100 years, but never had a way to travel more than a few feet. Enter the glassy-winged sharpshooter. The little leafhopper is commonly found in the southeastern United States, but appeared in Ventura County, California, about 25 years ago and quickly began a march north into central California's wine country, Backus said. A grape vine infected with Pierce's disease—the incurable plant ailment caused by the bacterium—withers and dies within two years. The disease can obviously wreak havoc on a vineyard.

This insect could decimate California's vineyards if officials don't act fast. USDA and university researchers used data acquisition techniques to find the exact moment that the insect transfers deadly bacteria to the vine. They hope to interrupt that cycle.

The small insect can spread a lot of destruction. The wine industry had a $45.4 billion impact on the California economy in 2002, according to The California Association of Winegrape Growers.

How does data acquisition play a role in helping California wine growers take back their vineyards?

Researchers knew that if they could get an in-depth, close-up look at the bug's feeding process, they'd have a good shot at figuring out how to stop bacteria transfer. Based on information gleaned in past work, the researchers decided to chart insect-feeding patterns. They would then synchronize the patterns captured through data acquisition with video images of the sharpshooters feeding.

In addition to Backus, the researchers were P. Houston Joost from the entomology department at the University of California, Riverside; David Morgan of the California Department of Food and Agriculture in Riverside; and Fengming Yan of the College of Life Sciences at Peking University in Beijing. Their work appeared recently in the Journal of Insect Physiology.

The researchers used a silver conducting paint to, in essence, glue a gold wire 50 micrometers wide and 1.5 centimeters long to the sharpshooter's body.

The insects with the golden wires were placed on one side of a diet chamber—a Plexiglas box divided in two by a special partition. The researchers put a sugar-water solution on the second side and connected the insects via their gold wires to the DI-720, a general-purpose data acquisition logger from Dataq Instruments of Akron, Ohio. It includes software for analyzing results.

As the sharpshooters' stylet—the mouthpiece it uses to feed—pierced the partition and the insects fed, their feeding style was graphed as waveforms. At the same time, a camera trained through a stereomicroscope recorded the feeding. Researchers then combined the information to tie the waveforms to each step of the feed, Backus said. In this way, the researchers broke down the feeding process step by step to isolate the exact moment the insect transferred bacteria from stylet to plant.

A step-by-step feeding chart gives researchers a clear way to see exactly how and when the disease is transferred, an important tool they can use in their quest to end that point of contact, Backus added.

Strike the Right Tone

In another part of the world, a piano maker is also gathering waveforms with data acquisition hardware and software, but to a much different end. Sound engineers at Czech piano maker Petrof use an extensive acoustic measurement system to assure that the sound quality of Petrof pianos is top of the line, said Jan Skala in the manufacturer's research department.

The company, more than 135 years old, is based in Hradec Králové and sells its upright and grand pianos in more than 80 countries under the names Petrof, Weinbach, Scholze, Rösler, and Fibich. Although it's attained a stately age, the piano maker relies on techniques that weren't around well over a century ago to improve sound.

"For decades, the grand and upright pianos have been designed through the cooperation of manufacturers and musicians," Skala said. "The empirical knowledge from cooperation is complemented more and more by musical acoustics and physics that enable us to describe the technical processes taking place inside and around the musical instruments and can help to improve the sound."

Five years ago, the piano maker set up its sound measurement chamber, which is specially equipped to do away with all echo, thereby isolating each piano note and making it possible for sound engineers to measure the pure sound from the instrument. They also can compare one piano to another inside the chamber.

"If we tried to take the measurements in a normal room, echoes would influence the readings," Skala said. "Since you wouldn't have the same echoes each time, it wouldn't be possible to compare measurements."

The chamber is made up of a large room built on springs to eliminate vibrations from vehicles passing by outside. Cone-shaped pieces of melted stone cover the chamber inside to prevent sound from echoing off the walls.

Inside the chamber, sound engineers test the complete instrument as well as individual parts like hammers, strings, and soundboards. During a test, two specially designed fingers made up of magnetic coils play the piano, stepping up the keyboard one tone at a time. A microphone picks up the sound coming from the instrument, sends it through an amplifier, and then into a personal computer, which takes a number of measurements, including maximum intensity of the tone—indicated by the sound pressure level. Software also measures the decay rate for the tone—the time it takes a note to fall from its maximum intensity to below 30 decibels. A third measurement produces wave diagrams for each tone.

It's those wave diagrams that challenged the engineers who designed Petrof's measurement system. The diagrams are essentially three-dimensional plots of time, frequency, and magnitude. The engineers wanted piano notes to sound at exactly the same moment a data acquisition system logged them so the visualization software inside the system could diagram the sound immediately. The software generates spectral and wave diagrams and other graphics that help engineers judge sound quality better than even the most finely tuned ear.

Many manufacturers turn to personal computers running Windows software in this situation, Skala said. But he felt his testers might find Windows occupied with other tasks at a vital moment, interrupting the data flow.

Petrof engineers got around the problem by implementing data acquisition hardware that lets them collect data continuously and interpret it in tandem in accompanying software. They run it on their personal computers, but don't use Windows. Instead, they use a data acquisition processor that circumvents the Windows system.

They use hardware from Microstar Laboratories of Bellevue, Wash., and Matlab visualization software from MathWorks in Natick, Mass.

There's no need to keep data acquisition at the plant.

Rick Bradshaw takes his company's data acquisition systems into the field to get instant feedback and make necessary changes on the fly. His company uses the system to simulate what Bradshaw calls down-hole conditions.

The firm, Fann Instruments Co. in Houston, sells instruments that monitor, moment by moment, the chemical properties of fluids used in the oil and natural gas industry.

Bradshaw is technical professional leader, research and development. The data acquisition systems Fann uses are perched atop offshore oil rigs or earthbound oil wells, or they're situated in control rooms just a helicopter flight away. Wherever they are, they're kept busy monitoring the conditions deep beneath the surface of the earth as fluids are poured into the well.

The fluids must be continually monitored because they're used in extreme conditions and their formations must be suitable to down-hole conditions. They need to be exactly the right consistency because drilling the well correctly and quickly saves Fann's clients a lot of money.

Czech piano maker Petrof isolates its pianos in an echoless chamber, then uses data acquisition technology to ensure that each note is as clear and precise as possible.

When oil and gas companies sink a well, they pump drilling fluids, also called drilling muds, through the middle of the rod while it's drilling into a formation. These fluids wash the stone, sand, or other debris and cuttings to the surface as the rod continues to sink, section by section. The fluids also fill the hole and keep the sides from caving in, Bradshaw said.

The cuttings are screened from the fluid at a spot called a mud pit. The mud can be reused.

"They can change the formula on the fly, depending on what type of formation you're going through," Bradshaw said. "Sand, tar, all kinds of different chemistries are used so the cuttings are more easily handled."

That's where the data acquisition system comes in. Fann uses CompactDAQ from National Instruments of Austin, Texas, and powers it with programmable LabView software from the same manufacturer. Fann personnel take samples continually while the mud is pouring and put them into their own test equipment at the surface, simulating pressure and temperature conditions the fluid is seeing in the well. The data acquisition system measures the fluid's reaction and software logs the results.

Fann does the same thing for cement, when it is pumped into the well. After the drill rod is taken from the hole, a pipe is placed inside. Cement is piped through to the well's bottom, where it rises between the walls of the hole and the sides of the pipe to secure the pipe in place.

"You know the pressure at which you'll pump the cement and you can determine the temperature down hole," Bradshaw said. "So you take a sample of the cement and put it in a machine at the surface that simulates, while you're pumping it, the conditions the cement is seeing 18,000 feet down," he said.

The cement is pumped in stages, as the hole is being drilled.
"Say you drill 1,000 feet and pump cement into the hole," Bradshaw said. "You already have the equipment in the pipe used to pump cement through the pipe. You don't want to pull it out until the cement is set.

"But it takes a gazillion dollars per minute to have crews out there, so as soon as you can, you want to pull the equipment out and keep drilling," he added. "Because the pipe isn't set all together, but a little at a time, you want to determine how long it takes to set so you can get it right out of there."

Technicians continually take samples while the cement is pouring. Sometimes samples are analyzed at the top of the site and sometimes they're flown by helicopter to one of the few hundred field labs Fann operates across the nation. The cement and fluids must be analyzed quickly, which is why helicopters are often standing by.

"Anytime anyone is drilling anywhere, the samples can be run back to the lab; there's four or five in every state," Bradshaw said. "Sometimes they'll send stuff back to the lab to say we're having a particular problem that we haven't had before. Sometimes it's routine measurement or to fix other specific problems."

Fann recently upgraded its data acquisition testing equipment to the National Instruments model.

"We'd been using some antiquated equipment, with low reliability and requiring a lot of service," Bradshaw said. "We're trying out this equipment that's more rugged. It can measure in minus 40 to 70 Celsius and it can go on an offshore rig, where shock and vibration can be pretty bad.

"We have air conditioned rooms on those rigs, but sometimes that air conditioning can go bad," Bradshaw added. "We have to be prepared for that."

There is no substitute for information. The one who has the facts can tap energy more efficiently, make better music, or perhaps save the economy of the State of California.

We've heard it before: Knowledge is power.