Siemens Automation System S7-400 - Manual (Page 25)

Installing the S7-400
2-9
Automation System S7-400 Hardware and 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.
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9
Division I Division II
I/O bus
Segment 1
I/O bus
Segment 2
Communication bus
Segment 1
Communication bus
Segment 2