Power Entry Modules (PEMs)
AXP1620 Shelf Description
AXP1620 Installation and Use (6806800E23E)
55
2.8
Power Entry Modules (PEMs)
The PEM is a Field Replaceable Unit (FRU) and can be replaced while the system is on, but
the power for the PEM being replaced (PEM A or PEM B) must be shut down at the external
source. Replacement can take place in under 30 minutes by a trained service person.
For important information on removing power before replacing a PEM, refer to
Recommended
Power-Off Procedures
on page 72
and
Power Entry Module (PEM)
on page 72
.
The PEMs are accessible from the rear of the shelf and connect to the power entry module
connectors on the backplane. A removable plastic housing covers the power feeds and returns
to prevent accidental shorting. The PEM also features an injector/ejector handle that provides
the hot swap mechanism for signalling the state of the PEM prior to removal.
Each PEM powers two separate power domains A and B and each domain supports two 80A
power rails to supply power to the AdvancedTCA slots.
The PEMs are hot-swappable and will not cause a fault when one is removed for replacement.
Two PEMs are required to support 2N+1 redundancy. If your system is configured for redundant
operation using two power feeds, they operate in load sharing where the total load is equal to
or less than what one power feed can provide.
Figure 2-8
PEM Backplane Connectivity
Power Entry Module
-48v_RTN
-48v
-48v
8 ATCA
Slots
FTM
SAM A
SAM B
SAM A
Backplane
IPMB_A
Front Panel
SAM B
IPMB_B
+12V
FTM
8 ATCA
Slots
Seated#
HA1
Logic_GND
Shelf_GND
IPMC_PWR
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