Backplane power distribution
32
Model 6476 User Guide
3 • System Architecture
•
Shelf Geographic Address (SGA)
—S2 is a DIP switch that enables the user to configure the shelf enumera-
tion feature, used for multi-shelf CompactPCI systems. The SGA effectively becomes a chassis identifica-
tion code, which is used to uniquely identify the chassis in a multi-chassis environment. This is currently
not used in most ForeFront applications, as most cards/devices are uniquely identified by an IP address,
which is manually configured for each device in the system.
•
Fabric Slot Geographical Address (FSGA)
—S3 is a DIP switch that enables the user to configure for a
redundant shelf enumeration feature, used in multi-shelf CompactPCI systems. For redundancy, the user
should configure this switch to the same address as that used for S2.
Backplane power distribution
Power is distributed in a CompactPCI system via the backplane. The backplane provides standard direct cur-
rent (DC) supply voltages as specified in
table 7
below
External power connections
The chassis provides a rear DC interface panel with -48V DC power interfaces for N+N power operation and
dual ground lugs, as shown in
figure 5
on page 20. The connectors are described in
table 8
.
Table 7. Power specifications
Mnemonic Description Nominal Value Tolerance
5 V
+5 VDC
5.0 V
±5%
3.3 V
+3.3 VDC
3.3 V
±5%
+12 V
+12 VDC
12.0 V
±5%
-12 V
-12 VDC
-12.0 V
±5%
GND
Ground
Table 8. Description of rear interface panel connectors
Item
Description
-48 VDC power termi-
nal
DC rear-entry module accepts 36–75 VDC at 7.0 A max input via Phoenix connec-
tor. Polarity should be applied as marked (negative—top position, positive—bot-
tom position). Each connector is independent and designed to power one 3U
power suppply module. There are three connectors provided for
N
+
N
power oper-
ation.
AC power interface
The AC power interface accepts 115 - 230 VAC (50–60 Hz), 5 amp maximum
(IEC 320 connector).
Ground lugs
The dual frame ground lugs must be used to connect the chassis to earth ground on
DC interfaces. Failure to do this will cause excessive RF emissions and could possi-
bly create a safety hazard. The double ground lug meets NEBS and will accept
Amp part # 606209-1. NEBS requires a double lug on DC chassis to ensure that
the ground connection will not rotate and become loose.
