Siemens SIMATIC PCS 7 Function Manual page 75

9. Select the required CP from the "Access point 1" drop-down list box. The list shows all
10.Select the "Master" check box.
11.If using a redundant CP, select the required CP from the "Access point 2" drop-down list
12.Activate the "Master" option button (default setting).
13.Click "OK".
Configuring the OS client for time synchronization
The OS clients only have simple network cards that neither send nor receive time message
frames. They query the time from the OS server in cycles and set their time accordingly. OS
clients query the time only from those OS servers from which they loaded data.
To configure OS clients for time synchronization, proceed as follows for each OS client:
1. Open the OS client in the PCS 7 project on the engineering station.
2. Select the "Time synchronization" editor from the tree view of WinCC Explorer.
Time synchronization (V8.0)
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devices installed on the computer or the symbolic names that are suitable for time
synchronization.
box.
This defines the OS server as the time master.
Configuring time synchronization
5.5 Configuring the time synchronization of the OS
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