Automatic cable tester checks multiple shielded conductors assembly cable connections. The tester uses logic circuitry to sequentially test all conductors and their shields to reveal any connection error in a GO-NO GO test

Dibb, G.

English

NASA Technical Reports Server

December 1966	 Brief 66-10659 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U.S. space program, 
to encourage their commercial application. Copies are available to the public at 15 cents each 
from the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Logic Circuitry Used to Automatically Test Shielded Cables 
The problem: 
In assembling multiple shielded conductors, a con-
ductor is sometimes connected to a pin to which the 
conductor shield should be connected and vice versa. 
Additionally, a conductor in one shield may be con-
nected to a pin to which another conductor in another 
shield should have been connected. After the connec-
tor assemblies have been properly potted, normal 
cable checking procedures do not reveal such errors. 
The solution: 
An automatic cable tester that uses logic circuitry to 
sequentially test all conductors and their shields to 
reveal any connection error in a GO-NO GO test. 
How it's done: 
An audio frequency (600 cps) generator is connected 
between an isolated common and any conductor in the 
cable with a logic indication of the specific conductor. 
A signal sensor, with an input impedance greater than 
one megohm, is connected between the common and 
any conductor except the one that the signal generator 
is connected to. A logic indication shows which con-
ductor the sensor is connected to and the sensor gives 
a logic GO-NO GO indication to show receipt or 
nonreceipt of the 600 cps signal. A ground is used to 
connect the common to any shield, and logic indica-
tion shows which shield is contacted. Logic circuitry is 
used to connect the signal generator, sensor, and
ground sequentially to each shielded conductor as-
sembly until the entire cable is tested. The logic uses 
three solenoid driven stepping switches to operate a 
panel of indicator lamps that show which conductors 
and shields are connected and whether or not the sen-
sor is receiving the 600 cps signal. 
The sensor receives a signal if: 
1. The signal generator and sensor are connected to 
conductors that are both in the same shield, no 
matter what shield is connected to common. 
2. The signal generator and sensor are connected to 
conductors that are in different shields and common 
is not connected to either of the shields concerned. 
Note: 
Inquiries concerning this innovation may be di-
rected to:
Technology Utilization Officer 
Headquarters 
National Aeronautics and Space 
Administration 
Washington, D.C. 20546. 
Reference: B66-10659 
Patent status: 
No patent action is contemplated by NASA. 
Source: George Dibb 
of General Electric Company 
under contract to 
NASA 
(Hq-60) 
Category 01 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000657 2020-03-11T17:41:35+00:00Z


Logic circuitry used to automatically test shielded cables

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