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Interlocking Anti-Crash And Conveyor Indexing Control Card For High-Speed Substrate Testers

IP.com Disclosure Number: IPCOM000101137D
Original Publication Date: 1990-Jul-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 4 page(s) / 114K

Publishing Venue

IBM

Related People

Jordan, SR: AUTHOR [+2]

Abstract

A single logic circuit card is described which enables a large number of sensors to be interlocked for operator safety as well as to protect testing mechanisms from damage and the inadvertent multiple indexing of conveyors and shuttles. A quick diagnostic aid is also provided for machine maintenance.

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This is the abbreviated version, containing approximately 52% of the total text.

Interlocking Anti-Crash And Conveyor Indexing Control Card For High-Speed Substrate Testers

       A single logic circuit card is described which enables a
large number of sensors to be interlocked for operator safety as well
as to protect testing mechanisms from damage and the inadvertent
multiple indexing of conveyors and shuttles.  A quick diagnostic aid
is also provided for machine maintenance.

      The circuit card is designed for use with testers, such as used
in the testing of substrates for the fabrication of printed circuit
boards, and movement of the substrates takes place by way of
conveyors, shuttles and robotic devices. The circuit interlocks a
total of twenty-two sensors located within tester drawers.  A typical
sensor signal enters and leaves the circuit card through
opto-isolators 10, as shown in Fig. 1.  The opto-isolators are used
to provide electrical noise immunity to the logic circuits on the
card.

      In actual operation, if a sensor indicates that a drawer is
completely opened or completely closed, the logic card will indicate
a safe operating condition.  But, if any drawer is in an intermediate
position, then there is a danger to the operator.  In this case, +5 V
will be present at an input to the NAND gate 11 and will result in
a 0 V output from this gate.  If any line going into NAND gate 12
is 0 V, then the output of NAND gate 12 is +5 V, disabling the
drive motors of robotic devices from operating.

      For anti-crash protection of machine parts, the interlock
circuitry is designed to protect both the testing hardware and the
substrates under test from damage.  It is designed to provide crash
protection even if the software is not operating correctly, or even
if an operator commands an inappropriate action to take place.  For
example, an anti-crash interlock would be such that an input/output
robot could not move in the X or Y direction if a gripper was in
the process of picking up parts, or the shuttle which slide...