Characteristic values of redundant automation systems   
A.2 Comparison of MTBF for selected configurations 
  CPU 410-5H Process Automation/CPU 410 SMART 
302  System Manual, 10/2013, A5E32631667-AA 
 
Switched distributed I/O, PROFINET, CCF = 2 % 
approx. 10  
The estimate applies if the process allows for any device to fail. 
Redundant CPUs with redundant I/O 
The comparison only took account of the I/O modules.  
 
Single-channel one-sided I/O 
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