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Technology
That’s Ready and Able to Inspect Those Cables
Public Safety
Originating Technology/ NASA Contribution
Attempting to locate a malfunctioning
wire in a complex bundle of wires or in a cable that
is concealed behind a wall is as difficult as trying
to find a needle in a haystack. The result of such
an effort can also be costly, time-consuming, and frustrating,
whether it is the tedious process of examining cable
connections for the Space Shuttle or troubleshooting
a cable television hookup. Furthermore, other maintenance
restrictions can compound the effort required to locate
and repair a particular wiring problem. For example,
on the Space Shuttle, once a repair is completed, all
systems that have a wire passing through any of the
connectors that were disconnected during troubleshooting
are affected and, therefore, must undergo retesting—an
arduous task that is completely unrelated to the original
problem.
In an effort to streamline wire inspection and maintenance,
two contractors supporting NASA’s Kennedy Space Center
invented the Standing Wave Reflectometer (SWR) in 1999.
In doing so, they leveraged technology that was first
developed to detect problems that could lead to aircraft
accidents, such as the one that resulted in the catastrophic
failure of TWA flight 800 in 1996. The SWR performs
a non-intrusive inspection that verifies the condition
of electrical power and signal-distribution systems
inside the Space Shuttle orbiters. Such testing reduces
processing delays and ensures safe operation of these
systems.
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Pedro
Medelius, chief technologist for ASRC Aerospace
Corp., helped invent the Standing Wave Reflectometer
(in right hand). The commercial version of
this device (in left hand) was spun off by
Eclypse International Corp. |
Commercial non-intrusive cable testers that preceded
the SWR proved ineffective for wire examination on
the Space Shuttle, because of the high-frequency test
signals they produced. These signals were incapable
of penetrating the dedicated signal conditioners (DSCs)
that are used on the Space Shuttle to modify transducer
outputs and other signals to make them compatible with
orbiter telemetry, displays, and data-processing systems.
Recognizing that the need for a low-frequency test
was critical to the success of the Space Shuttle, the
inventors of the SWR ensured NASA that their hand-held
technology could easily pass through DSCs without any
interference from signals outside of the intended bandwidth.
When troubleshooting potential instrumentation problems
in the orbiter, NASA technicians use the SWR tester
to find the precise location of a short or open circuit
in a cable. This ability saves NASA many hours of testing
on Space Shuttle by minimizing repair, retest time,
and any future troubleshooting efforts.
Eclypse International
Corp., a leading developer of
automated test equipment and associated test application
software solutions for commercial and military organizations
worldwide, further developed the SWR for use outside
of NASA. The resulting technology is currently being
used to test wires and cables in complex vehicle systems,
and has the potential for myriad consumer-driven applications,
as it features a menu-driven interface simple enough
for a novice to use.
Partnership
Kennedy’s Technology Transfer Office partnered with
the Research Triangle Institute and the Southeast Regional
Technology Transfer Center at the University of Florida
to market the patented SWR technology. The Technology
Transfer Office held a briefing at Kennedy, where the
SWR technology was demonstrated to more than 50 manufacturers
of electronic test equipment, including Corona, California-based
Eclypse. Following the briefing, each of the participating
manufacturers submitted a license application that
included a developmental plan and a market-application
plan. Eclypse, which had been exploring useful hand-held
troubleshooting tools that could augment and assist
maintenance personnel in locating short- and open-circuited
wiring in aviation vehicles, was awarded the exclusive
patent rights to the NASA SWR technology. Eclypse felt
that the SWR would provide a reasonable, low-cost design
concept with capabilities not found in the higher-priced
cable reflectometers that were currently available.
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The
Eclypse hand-held, non-intrusive analyzer finds
the precise location of a short or open circuit
in a cable. |
Two key factors contributed to Eclypse’s successful
procurement of the exclusive NASA license. First was
an open-architecture design concept that would allow
for the integration of future technologies into the
device, and second was a requirement that would provide
the company with access to the principal inventor of
the SWR during the beginning stages of product development.
Eclypse believed that involvement of key personnel
during development of its ESP commercial fault location
analyzer was vital for establishing an effective busines-plan
for the product.
Product Outcome
Although the ESP tag for Eclypse’s commercial
hand-held tester does not stand for “extrasensory perception,”
the product comes pretty close to having a “sixth sense”
in the way that it detects electrical malfunctions
with speed and precision. The company claims that the
ESP is
the fastest and easiest-to-use hand-held wire tester
available today.
Eclypse has developed three configurations of its ESP
product line based upon NASA’s SWR technology. The
original model, the ESP, provides a basic tool to locate
hard faults, such as opens and shorts, and has proven
to be very effective for reactive maintenance events.
This tool is preferred by commercial airlines. The
second-generation model, ESP+, retains all of the features
of the original, but also contains a flash memory that
allows the operator to store 32 test waveforms that
can be uploaded to any personal computer for comparison
and analysis. The ESP+ is preferred by military and
aerospace organizations for its data-collection capability.
The third configuration, the ESP Scientific model,
is a 100 MHz, +/- 250VDC version of the ESP. This model
provides a loading capability that has proven to be
very effective in detecting “soft” faults, such as
corrosion and degradation defects that can happen prior
to a wire breaking.
The ESP family of hand-held SWR meters provides the
means to determine the nature and location of discontinuity
in a cable by monitoring the impedance while injecting
an oscillating signal at one end of a cable and varying
the frequency of the oscillating signal. A numerically
controlled oscillator generates the signal, and a microprocessor
automatically makes the desired measurements and displays
the results.
Eclypse has made many improvements to the original
NASA prototype hand-held device. The NASA prototype
was physically large, fragile, and required specific
hexadecimal keypad entries to perform limited functions.
In contrast, the ESP weighs only 1 pound, 3 ounces,
and measures a mere 4 inches wide, 8 inches high, and
1 inch deep. (NASA has since replaced its hand-held
tester with the ESP for Space Shuttle maintenance and
test requirements.) Additional features integrated
by Eclypse include an alphanumeric, selectively back-lighted
liquid crystal display and keypad, a rechargeable battery,
automatic shutoff power management,
a serial data port, and a drip/splash-proof
and shock-resistant case.
The ESP has a specified range of 1,000 feet and can
operate successfully in temperatures ranging from -20
to +60 ºC. It also provides the capability to store
99 programmable settings for various cable and conductor
types, including coaxial, triaxial, multistrand single
conductor, and twisted pair. These presets can be recalled
quickly for testing, using the simple menu-driven interface.
Best of all, the ESP presents solutions in plain English
language and does not require visual waveform analysis
to determine the cause and location of a discontinuity.
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The
C-2 Greyhound full aircraft circuit-analysis
test at North Island Naval Air Depot, Coronado,
California. |
The ESP meter will benefit any industry that generates,
distributes, or consumes electrical energy to control
processes. Commercial customers include Emerson Network
Power, a manufacturer of precision-controlled, uninterruptible
power systems that include air conditioning and fluid
cooling systems, and APW Ltd., a designer, manufacturer,
and integrator of electronic products. In aerospace
and aviation, Boeing Aircraft, Lockheed Martin Corporation,
Delta Airlines, and Continental Airlines have applied
the technology.
At Seymour Johnson Air Force Base in North Carolina,
the 4th Component Maintenance Squadron is writing software
programs for the ESP tester to troubleshoot aircraft
wiring within 3 minutes, as opposed to the 20-plus
hours sometimes needed to manually complete such a
task with a conventional multimeter.
“The Eclypse tester is more accurate, faster, and easier
to use than anything I’ve seen, and we simply can’t
build anything that can do what it can in this shop,”
claimed Master Sergeant Stephen Hoggard, 4th Component
Maintenance Squadron chief, electronic and environmental
section.
In another military application, the ESP+ model
is ensuring the safety of U.S. troops serving overseas.
In October 2004, a U.S. EA-6B Prowler aircraft deployed
in Bagram, Afghanistan, required extra attention, because of intermittent navigational
problems within a critical cockpit display panel. These problems occurred multiple
times on nearly every flight, though were rarely observed on deck during routine
troubleshooting exercises. Most importantly, they compromised the safety of flight,
since the plane was flying in a war zone, through mountainous terrain at night.
The U.S. squadron maintaining the Prowler aircraft troubleshot the problem for
weeks, changing all associated removable components and performing wire checks,
all without success. To add to the difficulty, documentation detailing the circuits
for the problematic display panel was not available.
To facilitate further troubleshooting, the squadron decided to remove the wing
skin panels and expose the wire bundle containing the suspect circuits, so that
the bundle could be physically manipulated while under electrical test.
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Delta
Airline technicians Dane Swenson and Jim Elick use the Eclypse analyzer
to test generator feeders on a Boeing 767 commercial aircraft. |
The squadron tested the exposed wires with a common digital multimeter, a time
domain reflectometer, and then a hipot insulation-resistance tester, but could
not determine the “culprit” wire. Next, it performed a test with the ESP+ meter,
and the faulty wire that was the root of the navigational problems was revealed.
The wire was replaced and the problem was solved. The success with the ESP+ motivated
the squadron to use the meter to identify several other long-standing discrepancies
on other aircraft.
The ESP Scientific model is currently used by the Federal Aviation Administration
for impedance spectroscopy (measuring corrosion rates) and is preferred by formidable
research teams that include U.S. military branches, NASA, and aerospace firms.
All three ESP products are assuaging White House Office of Science and Technology
Policy (OSTP) concerns about aging wiring. The OSTP concludes that such issues
extend beyond aviation and are of national concern, while referring to the SWR-spinoff
technologies as “intelligent systems for identifying faults.”
On the whole, the economic benefits derived from the application of SWR technology
include: lower investment costs of troubleshooting equipment; reduced time and
effort to affect repairs; reduced time to validate repairs; and avoidance of
failure-induced downtime, all of which result in lower total operating cost.
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