SCSI DEVICE EXPANSION
MODULE
This
chapter
describes
the
SCSI Device Expansion
Module
and
its
components.
The
SCSI Device
Expansion
Module
has
room
for
up
to four SCSI
devices.
Two
positions
support
3.5
inch
non-removable
media
devices. The
other
two
positions
support
half
height
5.25 inch SCSI devices. The 5.25 inch
devices
may
be
removable
media
devices. Also 3.5 inch devices
may
be
installed
in
the
5.25
inch
positions.
Power Control
Two
types of
power
control are
provided
in
the SCSI Device Expansion
Module.
Two
RJ45
jacks
in
the
rear
of
the
module
allow daisy chaining of the
power
control signal
from
the
enclosure control board.
When
AC
power
is
connected to the module, a SCSI interface
with
terminator
power
present,
and
the
power
control signal is
in
the
ON
state, the
power
supply
in
the
module
turns
on.
If
unable to
use
the
power
control cable, a switch accessible
with
a
pointed
object
can
be
set
to allow
the
module
to
power
up
when
AC
power
is
connected
and
SCSI
terminator
power
is present.
SCSI Backplane
The SCSI
backplane
is
mounted
in
every
SCSI Device Expansion Module. The
backplane
has
a direct connection to
the
SCSI device
power
supply
and
accepts
up
to four 3.5
inch
drive
carriers
and
two
5.25
inch
drive carriers
per
module.
The
SCSI
backplane
has
all
the
module
level electronic devices
that
are
not
part
of the
power
supply
assembly.
The
SCSI
backplane
has
two
RJ45
external connectors for
power
control,
DC
failure
and
cooling
sensor
lines.
The
connectors are
on
very
small
boards
that
turn
them
90 degrees
and
these
are
considered
part
of
the
backplane
assembly.
The
two connectors are interconnected
pin
for
pin
on
the
backplane.
The
signals are
stubbed
out
to circuits
on
the backplane. These connectors
provide
daisy
chaining of the
wire
ored
signals
from
the enclosure control
board
to all
of
the SCSI Device Expansion
Modules
that
are
part
of a system.
When
present,
separate
SCSI only
modules
are
also
included
in
this single
daisy
chain. The
pin-out
has
been
made
symmetrical
and
redundant
so
that
cross-over
or
pin
to
pin
cables work.
S900RF/D4
4-1
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
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