International Business Machines Corporation

James E Frushour

Christopher John Majka

John E Swenson

Michael L Mahar

A system for testing conductor lines in a printed circuit board includes circuitry for the burning out of constricted regions of the printed circuit lines so as to insure that such defects are noticed. The system includes circuitry for measuring the resistance in a path through a printed circuit line under test and including connecting circuitry to a generator of an electrical pulse. A resistor network and switching circuitry is employed for adjusting the resistance of the path through a desired value. The electrical pulse is generated by the discharge of a capacitor previously charged to a predetermined value of voltage, the discharge occurring via a pulsing circuit switch which limits the duration of the pulse through a predetermined value of sufficiently short duration to prevent damage to the circuit board associated with excessive heating. Monitoring circuitry including a peak detector and comparators is employed for sensing a sudden change in test current amplitude, as well as test currents having amplitudes of an acceptable range, for terminating the test current pulse prematurely upon an indication of burnout, thereby to protect the circuit board.

Printed circuit conductor test system

A collision avoidance system for a two arm robot is direction sensitive. When the separation between the arms is sensed as equal to or smaller than a predetermined distance, the trailing arm is slowed to avoid a collision. The separation sensor generates a first 'slow' signal when the separation is a first predetermined distance, a second 'slow' signal when the separation is a second predetermined distance, smaller than the first, and a 'stop' signal when the separation is a third predetermined distance, smaller than the second. The polarity of the drive signals for the arms determine their direction, and polarity sensitive comparators determine the direction of each arm. When the first 'slow' signal is present and one arm is moving in the direction of the other arm, a speed reducing resistor is inserted in the circuit for the drive signal for the one arm to reduce its speed. When the second 'slow' signal is also present, a second speed reducing resistor is inserted in the drive signal circuit for the one arm, further reducing the velocity. A 'stop' signal causes a controller to stop both arms.

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Endwell, NY, United States of America

James E Frushour