Fujitsu M2361A Customer Engineering Manual page 141

(2) Rezero control operation
The head is returned to the reference cylinder (cylinder 0). The rezero
seek operation is classified into the coarse control operation and the
fine control operation as with the seek control operation; however, unlike
the seek control operation, the target speed is determined by the signal
generated by the reference voltage. The following explains how the rezero
seek operation is performed, assuming that the head is not in the Inner
Guard Band.
a. High Speed In (HSPIN)
The head is moved in the inner direction at 8 inches per second until
Inner Guard Band 1 (IGB1) is detected.
b. Low Speed In (LSPIN)
The head is moved in the inner direction at about 2.S inches per
second between the moment when IGB1 is detected in the neighborhood
of cylinder-2 (minus 2) and the moment when Inner Guard Band 2 (IGB2)
is detected.
c. High Speed Out (HSPOT)
The direction in which the head is to be moved is reversed, and the
head is moved in the outer direction at about 3.5 inches per second
between the moment when IGB2 is detected in the neighborhood of
cylinder-18 (minus 18) and the moment when IGB1 is detected.
d. Low Speed Out (LSPOT)
The head is moved in the outer direction at about 0.8 inches per
second after detecting 1GB!.
e. Rezero Out (RZOUT)
When the head enters the servo zone from 1GB! after it travels in the
neighborhood of cylinder-2 (minus 2), the head is moved to cylinder 0
with the target speed signal generated from the position signal.
f. Fine control
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After On Track is detected when the head is in the neighborhood of
cylinder 0, the Position control is performed in the same manner as
the seek control operation.
The rezero operation is performed from b. if the head is to be
returned from IGB1, or from c. if the head is to be returned from
IGB2; after that, the same control method is performed until the head
is positioned on cylinder O.
B03P-4825-0002A ••• 01