Siemens PCS 7, Руководство по установке

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3.2 Fault-tolerant (redundant) configurations
Introduction
The use of fault-tolerant components in a process control system minimizes the risk of a
production downtimes. A redundant design ensures increased availability of a control system.
This means that all components involved in the process have a backup and perform a portion
of the control tasks.
If a fault occurs or one of the process control system components fails, the still functional
redundant component takes over the control task.
Redundancy for PC stations in a PCS 7 plant
You can use redundant components in PCS 7 to ensure high availability of PC stations.
● Note the following properties for redundant server pairs:
Property Description
Reaction to server fail‐
ure
In a project with a redundant server pair, the advantage is that if one of the
servers fails, operator control and monitoring of the process can continue via
the redundant server.
Behavior from the client
perspective
From a client perspective, a redundant server pair behaves like one server.
Configuration You configure all of the configuration data for one server only. You then
download the configuration data to both redundant servers.
Configuration limits A redundant server pair behaves like one server. You can find additional
information on this in the section "Differences between multiple station sys‐
tems and single station systems (Page 17)".
● Note the following properties for redundant network components:
Property Description
Response to cable fail‐
ure (disruption in a ring
line)
The typical networks in a ring structure in PCS 7 feature cable redundancy.
The network remains in operation even if one cable fails.
Response to failure of
network adapters of
PCs or switches
If you use redundant network adapters and redundant network connections,
the network remains in operation even when a network adapter or switch
fails.
PC components of a PCS 7 system
3.2 Fault-tolerant (redundant) configurations
PCS 7 - PC Configuration (V8.2)
Installation Manual, 03/2016, A5E36200050-AB
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