Technical data

4-2
SCSI Device Storage Module
4
Power Supply
The power is supplied to the SCSI Device Storage Module in one of
three ways:
❏ System Power
❏ AC Power Supply Module
❏ DC Power Supply Module
System power is provided through an optional connector on the
bottom of the storage module (see Figure 4-4 on page 4-14). It plugs
into a receiver on the top of the XR system, and power is supplied
directly from the system’s backplane.
DC power to the module’s drives and fan assembly can also come
from a UL/CSA/VDE-approved 100W autoranging power supply
module. Power supply modules are available in both -48Vdc- and
115/230Vac-compatible versions, each providing +5Vdc and
+12Vdc to the enclosure. The power supply module is installed next
to the drives and is cooled by the air drawn through the module
chassis. Input power is provided to the power supply by the AC
power cord or DC wire assembly through the rear of the chassis.
The power supply distributes the power to the mass storage drives
through the backplane.
Drive Carriers
Injection-molded plastic cradles hold the drive and an adapter
board assembly. The cradle slides in from the front of the SCSI
Device Storage Module, plugs into the backplane and latches into
place. Two types of drive carrier assemblies are used.
The bottom device mounting holes are used for 5 1/4-inch
removable devices. A single high bezel filler panel is removed
when this assembly is installed. The assembly for 3 1/2- inch non-
removable media devices fits in either side of the SCSI enclosure.
SCSI addresses are selectable via a rotary switch soldered to the
adapter board.