Siemens SIMATIC PCS 7 Function Manual page 54

Fault-tolerant Solutions in PCS 7
3.3 Solutions for communication
Components
The following switches can be used:
● SCALANCE series of switches
● OSM (optical signal lines)
● ESM (electrical signal lines)
Configuration of the switches
For redundant linking of networks, configure one SCALANCE switch as the standby master
and one as the standby slave within a network segment. A redundancy manager (RM) must
be configured in each network segment to enable ring redundancy. Switches and data links
(network cable) connect the redundant networks. The switches configured in this way
exchange data frames with one other and synchronize their operating status (standby master/
standby slave).
You will find details of how to configure switches in the documentation for
Switches SCALANCE X under the following topics:
● Configuration using Web-Based Management and Command Line Interface
● Configuration and diagnostics via SNMP
Availability - redundant terminal bus
The entire transmission route can be configured redundantly. A transmission route remains
operational via a terminal bus if any of the network components fails.
In process mode, one switch automatically takes over the standby master function for linking
the networks. In error-free status, the data link to the other network is active only for the active
standby master. If this data link fails (for example, due to a defective cable), the standby slave
activates its data link.
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Modules for optical or electrical connection are used for the connection.
The connection to the OSMs is electrical or optical.
The connection to the ESMs is electrical.
Industrial Ethernet
Fault-tolerant Process Control Systems (V8.0)
Function Manual, 03/2012, A5E02779471-02