Siemens SIMATIC PCS 7 Function Manual page 56

Fault-tolerant Solutions in PCS 7
3.3 Solutions for communication
Availability - redundant fault-tolerant terminal bus
The entire transmission route can be configured redundantly. A transmission route remains
operational for communication on the terminal bus if any of the network components fails.
Connecting non-redundant networks and components
An integrated solution of network components and protection devices can be implemented for
a substation or process application using PRP-compatible SCALANCE X products. Connect
components having only one network connection to the redundant, fault-tolerant terminal bus
using the SCALANCE X204RNA . Select this connection for infrastructure components, for
example:
● Central plant clock (e.g. SICLOCK TC400)
● Domain controllers (DCs), DNS, WINS, DHCP, WSUS
● WLAN access point
● File server
Requirements
● A maximum of 2 non-redundant networks and components with only one network
connection for each SCALANCE X204RNA
● Two separate, redundant terminal bus networks
● Maximum distance to network node (component/switch):
– Standard Ethernet cable up to 10m
– IE FastConnect cable up to 100m
Recommendation for use
The PRP protocol requires the transmission of additional protocol information. The
transmission rate of 100 Mbps is not fully reached when PRP is used.
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Fault-tolerant Process Control Systems (V8.1)
Function Manual, 11/2014, A5E34878832-AA