Browse Prior Art Database

Failure Detector for Vacuum Sensor

IP.com Disclosure Number: IPCOM000046307D
Original Publication Date: 1983-Jul-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Barsotti, RH: AUTHOR

Abstract

A logic circuit is shown for detecting a failure of a tape column vacuum sensor.

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Failure Detector for Vacuum Sensor

A logic circuit is shown for detecting a failure of a tape column vacuum sensor.

Vacuum sensors are required in tape vacuum columns to insure that tape is properly in the column in order to prevent damage to the tape or drive. The logic circuit is arranged to sense, in order, selected indicators which verify that a vacuum is present in the column and will signal that the vacuum sensor is faulty if the sensor fails to provide a vacuum signal.

During tape load, the "Load Column" control turns on, providing a signal at input 10 to AND circuits 11 and 12. As the tape enters the column, tape position sensor 13 turns off the "tape below column center" output (tape is high in the column) to AND 11 and inverter 14. The inverter output operates AND 12 which sets gate latch 15, which provides a gate signal to AND 11. At this point, the column vacuum sensor 16, being verified, should indicate that vacuum is being sensed, degating AND 11.

If the vacuum sensor 16 has failed, AND 11 will remain gated, and as tape position sensor 13 indicates that the tape has gone below column center, its output will operate AND 11 to set error latch 16 to indicate a failure of the vacuum column sensor.

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