Communication Between Fault-Tolerant Systems And Pcs - Siemens CPU 410-5H Process Automation System Manual

Supplementary information
16.10 Communication via fault-tolerant S7 connections
Note
Fault-tolerant connections use two connection resources on CP b1 for the redundant
connections. One connection resource each is occupied on CP a1 and CP a2 respectively.
In this case, the use of further CPs in the standard system only serves to increase the
resources.
Figure 16-18 Example of redundancy with fault-tolerant system and fault-tolerant CPU
Response to failure
Double errors in the fault-tolerant system, i.e., CPUa1 and CPa2, or single errors in the
standard system, i.e., CPUb1, lead to a total failure of communication between the systems
involved. This can be seen in the previous figure.
16.10.3

Communication between fault-tolerant systems and PCs

Availability
When fault-tolerant systems are linked to a PC, the availability of the overall system is
concentrated not only on the PCs (OS) and their data management, but also on data
acquisition in the automation systems.
PCs are not fault-tolerant due to their hardware and software characteristics. They can be
arranged redundantly within a system, however. The availability of such a PC (OS) system
and its data management is ensured by means of suitable software such as WinCC
Redundancy.
Communication takes place via fault-tolerant S7 connections.
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CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 10/2013, A5E32631667-AA