Siemens SIMATIC PCS 7 - System Configurations with Distributed I;Os

Characteristic values of redundant automation systems
A.2 Comparison of MTBF for selected configurations
CPU 410 Process Automation/CPU 410 SMART
384 System Manual, 05/2017, A5E31622160-AC
Fault-tolerant CPU in stand-alone operation
Fault-tolerant CPU 410-5H in stand-alone mode
Factor
1
Redundant CPUs in different racks
Redundant CPU 410-5H in divided rack, CCF = 2%
Factor
approx. 20
Redundant CPU 410-5H in two separate racks, CCF = 1 %
Factor
approx. 38
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.