IBM Power 780 User Manual

92 IBM Power 770 and 780 (9117-MMD, 9179-MHD) Technical Overview and Introduction
2.10.5 12X I/O Drawer PCIe and PCI-DDR 12X Expansion Drawer SPCN cabling
System power control network (SPCN) is used to control and monitor the status of power and
cooling within the I/O drawer.
SPCN cables connect all AC-powered expansion units (Figure 2-31):
1. Start at SPCN 0 (T1) of the first (top) CEC enclosure to J15 (T1) of the first expansion unit.
2. Cable all units from J16 (T2) of the previous unit to J15 (T1) of the next unit.
3. From J16 (T2) of the final expansion unit, connect to the second CEC enclosure,
SPCN 1 (T2).
4. To complete the cabling loop, connect SPCN 1 (T2) of the topmost (first) CEC enclosure to
the SPCN 0 (T1) of the next (second) CEC.
5. Ensure that a complete loop exists from the topmost CEC enclosure, through all attached
expansions and back to the next lower (second) CEC enclosure.
Figure 2-31 SPCN cabling examples
Enclosures: Only the first two CEC enclosures of a multi-CEC system are included in
SPCN cabling with I/O expansion units. CEC enclosures number three and four are
not connected.
SPCN Connections
I/O Units
I/O
Expansion
Unit
*J15(T1)
*J16(T2)
I/O
Expansion
Unit
*J15(T1)
*J16(T2)
I/O
Expansion
Unit
*J15(T1)
*J16(T2)
I/O
Expansion
Unit
*J15(T1)
*J16(T2)
Secondary 3 CEC
No connection to third
or fourth CEC
Secondary 2 CEC
No connection to third
or fourth CEC
P1-C1-T8 (SPCN0)
Secondary 1 CEC
P1-C1-T9 (SPCN1)
P1-C1-T8 (SPCN0)
Primary CEC
P1-C1-T9 (SPCN1)

IBM Power 780 Specifications

General

Brand	IBM
Model	Power 780
Category	Server
Language	English