Siemens Simatic S7-400

Configuration Variants of the S7-400
6-9
Automation System S7-400 Configuration and Use
A5E0044271 1-02
TwoCPUsinaSplitRack
With split racks, the I/O bus and communication bus are divided into two
segments. A CPU can be installed in each segment.
Functionally, a split rack represents two electrically isolated racks on the same
mounting rail.
Figure 6-5 shows a configuration of a split rack with 2x9 slots.
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Device I Device II
Figure 6-5 Split rack
Advantages
Split racks are usually used for compact redundant S7-400H systems (two devices
or systems in a single rack).