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