Communication Between Fault-Tolerant Systems And Pcs - Siemens SIMATIC S7-400H System Manual

11.5.3

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 retention, but also on data acquisition
on the automation systems.
PCs are not fault-tolerant, on account of their hardware and software characteristics. They
can be configured redundantly within a system, however. The availability of this kind of PC
(OS) system and its data management is ensured by means of suitable software such as
WinCC Redundancy.
Communication take place via fault-tolerant connections.
The "S7-REDCONNECT" software package, V1.3 or higher, is essential for fault-tolerant
communication on a PC. It supports the connection of a PC to a fiber-optic network with one
CP, or to a redundant bus system with 2 CPs.
Configuring connections
The PC must be engineered and configured as a SIMATIC PC station. Additional project
engineering of the fault-tolerant communication is not necessary at the PC end. Connection
configuration is handled by the STEP 7 project in the form of an XDB file at the PC end.
You can find out how to use STEP 7 fault-tolerant S7 communication to integrate a PC into
your OS system in the WinCC documentation.
Figure 11-7
S7-400H
System Manual, 09/2007, A5E00267695-03
Example of redundancy with fault-tolerant system and redundant bus system
11.5 Communications via fault-tolerant S7 connections
Communication
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