Browse Prior Art Database

Autolock Open/Short Detection

IP.com Disclosure Number: IPCOM000103453D
Original Publication Date: 1990-Nov-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 31K

Publishing Venue

IBM

Related People

Purkett, JC: AUTHOR

Abstract

Disclosed is a method for detecting electrical open or short conditions in solenoid-type DASD actuator latches. The circuit utilizes a sense resistor to allow open or short conditions to be detected before energizing the autolock coil (see the figure).

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Autolock Open/Short Detection

      Disclosed is a method for detecting electrical open or short
conditions in solenoid-type DASD actuator latches.  The circuit
utilizes a sense resistor to allow open or short conditions to be
detected before energizing the autolock coil (see the figure).

      The operation of the circuit is based upon sensing the voltage
across the connections to the autolock coil when the driver circuit
is "off".

      The sense resistor Rx is chosen such that the current provided
will not hold the latch unless the Driver is sourcing current.  When
the Driver is "off", the voltage Va is a fraction of the supply (+S)
and is determined by:
   Va = S * Ra / (Ra + Rx)

      The voltage Va is checked (using either comparators or an
analog-to-digital converter) before energizing the autolock coil.
The following comparisons are made:
   If Va is "close" to +S, then the connections or coil are "open".
   If Va is "close" to 0, then the connections or coil are "shorted".

      Disclosed anonymously.