NASA Technical Reports Server (NTRS) 20020086292: Signal Isolators

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by  NASA Technical Reports Server (NTRS)

Public Sofefy
NASA Tech Briefs, a monthly publication intended to The division purchased commercial isolation
advise potential users what new NASA technology is modules that solved the immediate problem. But the
available for transfer, is a major source of spinoff Water Division's tight budget demanded a more cost
applications. On occasion, Tech Briefs reports contain effective long term solution.
sufficient information by themselves to inspire and Division electronic technician Bob Ervolino read
guide development of a spinoff product or process. an article in Tech Briefs - "Output Isolation and
More often, Tech Briefs Protection Circuits" - describing an Ames Research
provides an initial lead; Center solution to a problem similar to the Water
prospective users can Division's. He sent for the TSP, studied details of the
follow up by requesting Ames invention, and learned the name of the vendor
a Technical Support supplying the isolation circuit described in the article,
Package (TSP) that Analog Devices, Norwood, Massachusetts. That
supplies more detailed company suggested other devices, which the Water
information about a Division acquired and installed. Ervolino reports that
particular innovation the information supplied by Tech Briefs and the
(see page 141). vendor solved the problem and saved the Water
The City of Division more than 50 percent of the cost of
Dubuque (Iowa) used commercial signal isolators. The solution - the
the latter approach to signal isolators - is pictured below.
A NASA solve a problem with the computer system operated
by the Water Division of the Utility Department. The
technical system gathers data, both analog and digital, from
remote tanks, pumping stations, wells and the
repod division's main plant.
Shortly after the computer system became
provided a operational, the division began experiencing failures
of the analog inputs ranging from signals out of
solutionf or tolerance by more than 30 percent to intermittent -
and sometimes complete - loss of signals.
computer Investigation traced the problem to lack of signal
isolation on the analog input cards, which made
system the inputs vulnerable to interference from storms
and machinery. Most of the problems originated in
failures the main plant pump room shown above; the
pumps have thermocouples mounted on the
bearings and their signals are not isolated from the
computer inputs.