Network Environment In Redundant, High-Availability Networks - Siemens SIMATIC PCS 7 Function Manual

Structure
The following figure illustrates the recommended configuration for a PCS 7 plant in a work
group with a central time clock:
Time synchronization in a work group
The time is synchronized within a work group as follows:
● Time synchronization via plant bus
● Time synchronization via terminal bus
2.8.5

Network environment in redundant, high-availability networks

Introduction
Always install redundant networks in a PCS 7 plant as a precaution against production losses
caused by failures in the network connections. This will ensure that communication via the
redundant network will remain intact if an area of the terminal bus fails. The domain controllers
synchronize one another's time on the basis of Windows mechanisms.
Central plant clock
The SICLOCK TC 400 is suitable for operation as a central plant clock. The SICLOCK can
distribute the time signal directly to the plant networks.
Time synchronization (V8.0)
Function Manual, 03/2012, A5E02779849-02
The plant bus is synchronized using the SICLOCK.
The OS servers and the automation systems receive the time from the central plant clock.
These are time slaves.
The OS clients receive their time from an OS server. OS clients only receive the time from
those OS servers from which they also loaded the server data.
2.8 Network environment of a PCS 7 plant
Fundamentals
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