Segmented Cr - Siemens S7-400 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.
SEG1
2-8
1
1 2 3 4 5 6 7 8
SEG1 SEG1 SEG1 SEG1 SEG1 SEG1 SEG1 SEG1
I/O bus
Segment 1
Communication bus
S7-400 and M7-400 Programmable Controllers Hardware and Installation
11
SEG2
9 10 11 12 13 14 15 16
SEG1 SEG1 SEG2 SEG2 SEG2 SEG2 SEG2 SEG2
I/O bus
Segment 2
17 18
SEG2 SEG2
A5E00069481-04