Siemens Simatic PCS 7 Function Manual page 70

High availability solutions in PCS 7
4.3 Solutions for communication
High availability communication solutions
The following communication solutions are offered to prevent a possible failure:
● Ring structure in an electrical network.
The connection to the switches is electrical.
● Ring structure in an optical network with switches and FO cable.
The connection to the switches is electrical or optical.
● Ring structure in a combined network with optical and electrical switches and a FO cable.
The connection to the switches is electrical.
● Ring structures as optical, electrical and combined networks with transmission rates up to
1 Gbps based on modular SCALANCE X switches
The use of switches from the SCALANCE series is recommended. Modules for optical and
electrical connection are available for these switches.
Configuration - ring structure
The following figure represents a high availability plant bus in a ring structure with switches.
The following automation systems can be used:
● AS 41xH
Availability - ring structure
In this system, one CP 443-1 may fail in each subsystem of the AS without this affecting the
complete system.
The plant bus (identified by an * in the following figure) is equipped with switches for high
availability operation. Each OS server is wired to two switches. The bus can be separated at
any location. The overall system remains functional even if a switch fails. The redundant OS
partner server then communicates via the functional switch. The same scenario applies to the
switches that each have a CP of a subsystem of the H system connected.
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High Availability Process Control Systems (V9.0)
Function Manual, 05/2017, A5E39221836-AA