Installing the S7-400
2-9
AutomationSystem S7-400 Hardwareand Installation
A5E00850741-01
2.4 Subdivided CR

Characteristics

The “subdivided” characteristic relates to the configuration of the CR. In the
(non-divided) CR the I/O bus and communication bus are continuous and
interconnect all the slots; in the subdivided CR, however,the I/O bus and
communication bus consist of two segments each. The UR2-H rack used here
functions as two electrically isolated UR2 racks on the same rack profile.
A subdivided CR has the following important characteristics:
•The communication bus and I/O bus are subdivided into two segments with 9
slots each.
•Each segment represents a self-contained CR.
The following figure shows a divided CR with a divided I/O bus and communication
bus.
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Division I Division II
I/O bus
Segment 1
I/O bus
Segment 2
Communication bus
Segment 1 Communication bus
Segment 2