Technical data

Configurations for time synchronization of a PCS 7 plant
3.3 Configurations for time synchronization in a work group
Time synchronization (V7.1)
Function Manual, 03/2009, A5E01216578-01
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Time synchronization on the plant bus
● Time master is the SICLOCK connected to the plant bus as the central plant clock. It
sends a high-precision broadcast time signal on the plant bus. Time synchronization is
set in SIMATIC mode.
● The OS servers are configured as what are known as cooperative time masters. If the
SICLOCK no longer sends a time signal, then an OS server becomes active time master
and then sends time signals itself on the plant bus, as a replacement.
● Configuring the automation systems:
– The automation system with standard CPU (without integrated Ethernet interface) is
configured for operation as a time slave.
– The automation system with integrated Ethernet interface is configured for operation
as a time master.
● The SIMATIC PCS 7 BOX and SIMATIC PCS 7 AS RTX are configured (see the table
below). Time synchronization is set in NTP mode.
Time synchronization on the terminal bus
● During the runtime of a PCS 7 project, an OS server adopts the time signal received from
the plant bus. This OS server sets the system time of the other OS servers. You make the
settings in the WinCC "Time Synchronization" editor.
● The OS clients are configured as time slaves and receive their time signal from an OS
server, from where server data is downloaded.
● PC stations without WinCC time synchronization, such as a BATCH PC or engineering
station, are synchronized using a DCF 77 reception service, which must be installed
separately. An OS server can be operated as a time master.
Further information
● Section "Configuration steps for time synchronization with central time master in a work
group (Page
56)"