Siemens SIMATIC CPU 410 System Manual page 324

Supplementary information
18.8 Basics and terminology of fault-tolerant communication
Figure 18-7
If the active subconnection fails, the already established second subconnection automatically
takes over communication.
324
Example that shows that the number of resulting partial connections depends on the
configuration
CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC