Solutions For Simatic Batch - Siemens SIMATIC PCS 7 Function Manual

Fault-tolerant Solutions in PCS 7

3.7 Solutions for SIMATIC BATCH

that the OS clients can control and monitor the automation process continuously, the OS clients
are distributed between the redundant OS servers with specification of a preferred OS server.
The failure of some OS clients can therefore be tolerated because the other clients remain
connected to the process.
Preferred server
A "preferred server" is an OS server in the redundant OS server pair that the OS client connects
to preferentially. A preferred server can be defined separately for each OS client in order to
ensure permanent operability. The distribution of the OS clients between the OS servers
distributes the loads and increases the performance of the system as a whole.
Operating principle
If the active OS server fails, the process values on all of the connected OS clients are no longer
updated and there is no operator control on these OS clients during the failover. Other OS
clients that are connected in parallel to the redundant OS partner server are not affected by
this. The plant operator can therefore change to these OS clients if needed.
Generally, the following applies: The OS clients always connect to the specified preferred
server if it is available. If it is not available, the OS clients automatically connect to its redundant
OS partner server. If you do not specify a preferred server for an OS client, it will connect to
the OS server that has the master identification.
When the failed OS server comes online again, the OS client automatically reconnects to its
preferred server. The master identification of the OS server does not change even when the
failed OS server comes back online.
Additional information
● Section "How to configure an OS client for permanent operability (Page 145)"
● Online help for
3.7 Solutions for SIMATIC BATCH
Redundant BATCH servers
SIMATIC BATCH enables you to configure two BATCH servers redundantly for fault-tolerant
operation. This ensures that you can monitor and control your batch process at all times.
Functionality
Redundant BATCH servers monitor each other in runtime to detect the failure of a BATCH
server as early as possible.
If one of the two BATCH servers fails, the process can be controlled over the second BATCH
server after the failover.
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WinCC
Fault-tolerant Process Control Systems (V8.0)
Function Manual, 03/2012, A5E02779471-02