E.I. DuPont Plant Saves Development Dollars with PC-Based Data Collection
and Analysis System

March 29, 1993 - Austin, TX - The E.I. DuPont May plant (Camden, SC) has
found a way to save time and money by using a personal computer (PC),
software, and hardware to conduct research on its high-speed fiber
spinning manufacturing process.

DuPont has combined LabWindows automatic code-generating software and a
high-performance multichannel data acquisition (DAQ) board, both from
National Instruments, to create a low-cost, flexible, PC-based system that
monitors a nylon fiber spinning machine. The DOS-based system looks for
events - such as a break in the fiber- that interrupt the manufacturing
process and cost thousands of dollars in downtime while the crew finds and
repairs the fault. DuPont uses the results from the research station to
optimize the performance of similar machines throughout the May plant.

High-Speed System Monitors Multiple Parameters 

DuPont uses LabWindows and the AT-MIO-16F-5 plug-in board to continuously
monitor 64 sensors that check physical parameters such as the viscosity of
the molten nylon; the pressure buildup as the nylon goes through filters;
the pressure, temperature, and rate-of-flow of air cooling the molten
nylon into solid fiber; fiber tension; and the power level on multiple
drive rolls and heaters. As soon as the system senses that one or two
channels have exceeded certain predefined limits simultaneously,
LabWindows dumps a high-speed "snapshot" of data to disk. This snapshot
includes several seconds worth of data from before, as well as after, the
event. Snapshots usually range from tour to eight seconds in length, but
may be longer, containing more than a million data points.

Data Analysis and Presentation Key to Successful System Operation

Maarten Meinders, a DuPont Senior Research Engineer, used the automatic
code-generating features in LabWindows to write a custom analysis program
that manages the large amount of data generated by the sensors. LabWindows
superimposes 64 miniplots on one screen so engineers can look for sensor
anomalies. Engineers can click on specific plots to examine in closer
detail, or select regions of the plots and perform instant statistical
comparison within regions. Once engineers determine the regions in which
the event occurred, LabWindows prints a one-page comparison of the same
regions for the remaining sensors. LabWindows libraries also perform more
advanced analysis, such as digital filtering, FFT, spectrum analysis, and
time-shifting, on the plots.

Increased Functionality and Flexibility at a Reduced Cost Prove Beneficial


Meinders says that cost is a main reason for choosing a PC-based system. "A
VAX-based system costs at least $50,000 for the computing power alone,"
says Meinders. "Several years ago, a team at another DuPont plant spent
$200,000 on a (VAX-based) solution for a similar problem." In comparison,
Meinders spent $33,000 for a 486-based, 25 MHz PC, LabWindows, the
AT-MIO-16F-5, signal conditioning hardware, and a prefabricated room to
protect the PC.

The real-time capabilities of LabWindows and the AT-MIO-16F-5 have improved
the efficiency of the May plant.

"We can do fundamental research now that we couldn't do before," says
Meinders. "We can look at several sensors at once, very fast. We
understand the process more - it's improved our operability and quality.
This, in turn, helps us continuously update our analysis programs."

About LabWindows 

LabWindows is a set of software tools and libraries for developing programs
in Microsoft C and QuickBASlC under DOS for instrument control, data
acquisition, analysis, and presentation. LabWindows can control GPIB, VXI,
and RS-232 instruments, and plug-in DAQ boards. LabWindows includes an
Instrument Library with over 260 ready-to-use high-level drivers for
controlling specific programmable instruments. LabWindows also has
Analysis Libraries with functions for array and matrix manipulation,
complex arithmetic, statistics, Fast Fourier Transforms, curve-fitting,
digital filters, real and complex vector and scalar operations and
high-level statistical analysis.

About the AT-MIO-16F-5 

The AT-MIO-16F-5 is a high-performance, multifunction analog, digital, and
timing I/O board for PC AT and compatible computers. It has a 12-bit
sampling ADC with up to 16 single-ended or eight differential analog
inputs and a 200 kHz sustained sampling rate, two 12-bit DACs, eight lines
of TTL-compatible digital l/O, and three 16-bit counter/timer channels.

National Instruments
6504 Bridge Point Parkway, Austin, TX 78730-5039
512-794-0100;  800-433-3488;  fax: 512-794-8411

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