Segmented Cr - Siemens SIMATIC S7-400 Hardware And Installation Manual

Installing the S7-400
2.3

Segmented CR

Properties
The "segmented" characteristic relates to the configuration of the CR. In the
(non-segmented) CR the I/O bus is continuous and interconnects all 18 or 9 slots;
in the segmented CR, however, the I/O bus consists of two I/O bus segments.
A segmented CR has the following important characteristics:
The communication bus is continuous (global), whilst the I/O bus is divided into
two I/O bus segments of 10 and 8 slots respectively.
One CPU can be inserted per local bus segment.
The two CPUs in a segmented CR may be in different operating states.
The two CPUs can communicate with each other via the communication bus.
All the modules inserted in a segmented CR are powered by the power supply
module at slot 1.
Both segments have a common backup battery.
The following figure shows a segmented CR with divided I/O bus and continuous
communication bus.
2-8
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I/O bus
Segment 1
Communication bus
S7-400 and M7-400 Programmable Controllers, Installation Manual
I/O bus
Segment 2
C79000-G7076-C424-01