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der is illustrated below. Arrows indicate the order in which words are allo-
cated to Units.
C2000H CPU Rack
C2000H Duplex CPU Rack
CPU I/O Rack
Expansion I/O Rack
Expansion I/O Rack
Expansion I/O Rack
To other Expansion I/O Racks
Starting point
Starting point
I/O Control Unit
I/O Interface Unit
Empty slot (no words allocated)
I/O Control Unit
Duplex
Unit
CPU
CPU
CPU
I/O Interface Unit
I/O Interface Unit
To other Expansion I/O Racks
Although a Remote I/O Master Unit (called a Master for short) mounted to a
Rack, and any Remote I/O Slave Units connected to it, are not allocated I/O
words, any Units on the Slave Racks or other Remote I/O Units connected to
the Master are allocated I/O words.
Units mounted to a Slave Rack are allocated words according to the slot
where the Master is mounted. If IR 16 is the last word allocated to the Unit to
the left of the Master, IR 17 would be allocated to the first Unit on the left end
of the first Slave Rack connected to the Master. Allocations would continue to
all of the Units on all Slave Racks before continuing to the Unit mounted to
Remote I/O Systems
IR Area
Section 3-3