I/O configuration variants   
4.6 System and media redundancy at the PROFINET IO interface 
  CPU 410-5H Process Automation/CPU 410 SMART 
66  System Manual, 10/2013, A5E32631667-AA 
The figure below shows the system-redundant connection of nine IO devices using three 
switches. This configuration, for example, allows you to arrange IO devices in several 
cabinets. 
 
Figure 4-14  PN/IO with system redundancy 
 
 
Note 
Logical structure and topology 
The topology itself does not determine if IO devices are connect
ed one-sided or in a 
configuration with system redundancy. This is determined in the course of configuration. You 
can configure the IO devices in the first figure, for example, as one
-sided instead of the 
-redundant setup.