System Configurations With Distributed I/Os - Siemens SIMATIC CPU 410 System Manual

Characteristic values of redundant automation systems
A.2 Comparison of MTBF for selected configurations
Fault-tolerant CPU in stand-alone operation
Fault-tolerant CPU 410-5H in stand-alone mode
Redundant CPUs in different racks
Redundant CPU 410-5H in divided rack, CCF = 2%
Redundant CPU 410-5H in two separate racks, CCF = 1 %
A.2.2

System configurations with distributed I/Os

The system with two fault-tolerant CPUs 410-5H and one-sided I/Os described below is
taken as a basis for calculating a reference factor which specifies the multiple of the
availability of the other systems with distributed I/Os compared with the base line.
384
Factor
1
Factor
approx. 20
Factor
approx. 38
CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC