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Entry type: FAQ Entry ID: 16620294, Entry date: 11/06/2014

How do you configure time synchronization in Windows domains?

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In plants in which process control systems are implemented there a numerous components that exchange data with each other. In most plants the processes and data have to be controlled synchronously.

An essential aspect of this is that Windows compels the computers to use their own time synchronization via the Simple Network Time Protocol. If there is a time discrepancy between one of the computers belonging to a domain and domain controller 1, this computer loses access to all the network resources.

However, because the Windows synchronization only guarantees a time synchronization of ± 2 seconds, the synchronization must be configured with a specified computer. Here, for every computer (ES, server and client) the domain controller 1 must be entered as "Computer 1" in the time synchronization. You can also enter an additional domain controller as "Computer 2" if this is available.
In this case, the access points on the terminal bus can only be configured as master. This makes synchronization of the connected controllers possible.
You can found the setting can WinCC Explorer> Time Synchronization.

Fig. 1: "Time Synchronization" settings in Windows domains

If the WinCC servers belong to a Windows domain, and there is a specialized device (such as SICLOCK) working as the time master on the system bus, it is imperative to ensure that the time on the SICLOCK is identical to that on the domain controller. The best solution is to equip both with an external time receiver (such as DCF77). In this case, the connected PCs are synchronized by the domain controller and the connected controllers are synchronized by the SICLOCK.

Further Information
More information on the topic of "Time synchronization" is available in the WinCC Online Help in Entry ID: 16622902 "Which settings need to be taken into consideration during time synchronization?" and in the group entry 86535497 " Time synchronization - Time synchronization in the automation environment"

Creation Environment
The screens in this FAQ response were created with PCS 7 V6.

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