Specifications
1.4.7 Spindle Lock and Brake
,
These drives
are
provided with
an
integral
fall·sal.
spindle
lock
and
brake.
ThIs
lOIenold
operated.
mechanical
brake
is actuated when
de
power
is applied to the drive, allowing the spindle to rotate. When the drive is powered
off,
the
solenoid is deae:ttvated
allowing
the brake to engage
the
spindle.
This
prevents the
possibility
of
disk
move·
ment
during
shipping or
movement
of the drive. During spin down, the
brake
decelerates the spinning
disks
quickly
to
reduce
the
amount
of
time
that
the heads are In unltable flight.
Se.
figure
1-4.
)
STEPPER
MOTOR
BRUSHLESS
DC
SPINDLE
MOTOR
FIGURE 1-4. SPINDLE LOCK
1.4.8
Read/Write
Head
Shipping
Zoae
The
unused
area
of the disk surface. Inside
the
data
bands, is designated
as
a "shipping
zone."
The
heads
should be
positioned
to
this
area
via software before
the
drive
15
powered off. prior
to
moving
or
shipping
the
drive. This en-
sures that if the
drive
is
exposed
to
severe handling
(shock).
the
data
storage
area
of
the disk surface
will
not
be
damaged
by
heads
movement
on
the
disk(s).
See
figure }-5.
1.5
FUNCTIONAL OpERATIONS
1.5.1 Power SequencIDl
The required power-on
sequence
for early production
units
(1.8., 706/712 that are
MLC
4
or
less)
is that both
the
5
and
12
volts supplies
be
M
on
" within
20
seconds
of
each
other.
The
order
is
not
important.
No power-on
sequence
is required for
MLC
5 and above.
All
drtves have a
speed
sense ctrcult
to
prevent stepping
until
the
disk
is rotating
at
the
proper
speed
(3,600 rpm). A READY signal
will
be
presented
to
the
controller inter- l
face
once
the
disk is
up
to' Its normal rotational
speed
(:t
2%)
for two seconds.
At
.READV
time, after
an
initial
power-up, the drive will recalibrate Itself
to
track
00.
When the recallbration
procedure
Is complete. SEEK COM-
PLETE
will
go
true. Normal
seek
and
read
functions
can
now
begin. Refer
to
paragraph
2.6.
! i
·1.5.2 Drive SelectlOD )
Drive selection occurs when
one
of
the
DRIVE SELECT Ilnes
II
activated. Only
the
drive appropriately jumpered
will respond to
the
input signals.
and
the
output
signals of that drive
are
then
gated
to
the
controller.
1·8