Planning Time Synchronization; Selecting The Time Master; Selecting The Central Plant Clock - Siemens SIMATIC PCS 7 Function Manual

Planning time synchronization

4.1

Selecting the time master

Selecting the time master
On a time-synchronous PCS 7 plant, you require a time master to which the additional plant
components can be synchronized. The table below lists the components that are used as time
masters, depending on the network environment:
Time master With time
source ...
SICLOCK Central clock:
Not
synchronized,
or
synchronized
(e.g. via GPS
or DCF 77)
OS server - BIOS clock
- GPS
- DCF 77
Domain controllers - GPS
- DCF 77
- NTP server
PC - BIOS clock
- GPS
- DCF 77
- NTP
4.2

Selecting the central plant clock

Introduction
You should always synchronize all automation processes using a standard time. In the case
of PCS 7 plants, we recommend performing synchronization by means of a central plant clock.
The central plant clock controls the time for the entire PCS 7 plant, and synchronizes all other
plant components via their interfaces.
A GPS or DCF 77 signal should be used as the time source for the central plant clock.
Time synchronization (V8.0)
Function Manual, 03/2012, A5E02779849-02
Provides the Time master
time via ... forwards the time to...
Terminal bus Domain controller
Terminal bus OS server
Plant bus Automation systems
Terminal bus OS clients
Plant bus CP of the OS servers that are
active time masters
Terminal bus OS server
All OS servers as
time masters
Forwards the time to ...
-
Terminal bus with OS servers and
OS clients
-
Automation systems
OS clients
Plant bus, including the automation
systems
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