Browse Prior Art Database

Multi-loop Support using One Release of Servo Code and Electronics

IP.com Disclosure Number: IPCOM000108792D
Original Publication Date: 1992-Jun-01
Included in the Prior Art Database: 2005-Mar-22
Document File: 2 page(s) / 87K

Publishing Venue

IBM

Related People

Anderson, TB: AUTHOR [+7]

Abstract

This disclosure proposes that the actuator position control loop and the spindle control loop be designed such that only one set of electronics and microcode be used to support a wide variety of file designs. Each file design may have different servo or spindle parameter values which would require a change in the control gains of the associated loop. For example, the torque constant of the actuator may be different. If the control gains were hard wired or hard coded into the servo control algorithm, then each version of the file would require a different part number for the electronics.

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

Multi-loop Support using One Release of Servo Code and Electronics

       This disclosure proposes that the actuator position
control loop and the spindle control loop be designed such that only
one set of electronics and microcode be used to support a wide
variety of file designs.  Each file design may have different servo
or spindle parameter values which would require a change in the
control gains of the associated loop.  For example, the torque
constant of the actuator may be different.  If the control gains were
hard wired or hard coded into the servo control algorithm, then each
version of the file would require a different part number for the
electronics.

      It is recommended that the file disk enclosure (DE) be designed
such that the file type is identifiable during the file power-on
sequence.  After the file type has been identified, then the
appropriate control gains are selected by the electronics.  Several
methods of identifying the file type and selecting the correct
control gains are shown below.

      There are multiple ways to uniquely identify file DEs so that
the correct servo and/or spindle control gains can be selected for
use with that specific DE:
1.  In the factory at build time, the necessary control constants for
each different DE version could be written into a reserved area on
one or more disks in the file. Anytime after that, when the file is
spun up and the actuator is brought to the home cylinder, the
reserved area would be read and the control constants would be loaded
into the servo processor.
2.  The DE would be designed with some kind of jumper arrangement
which is set in the factory.  After power-on, the electronics would
read the jumper selection and pick the appropriate control gains from
a table, which is part of the electronics, for that jumper setting.
3.  Before starting the spindle motor or during motor spin-up, while
accelerating up to normal run speed, the file electronics could
attempt to read from each data head in de...