Time-Of-Day Synchronization - Siemens S7-1200 TELECONTROL Operating Instructions Manual

Configuration and operation

4.8 Time-of-day synchronization

4.8 Time-of-day synchronization
With applications that require time-of-day synchronization (e.g. telecontrol), you need to
synchronize the time of day of the CP regularly. If you do not synchronize the time of day of
the CP regularly, there may be deviations of several seconds per day in the time information
of the CP.
When using an external time source, the S7-1200 station can obtain the current time of day
both via the CPU as well as via a CP. Note the behavior described below.
With the S7-1200 there is no forwarding of the time of day from the station to the subnet.
Note
Recommendation: Time-of-day synchronization only by 1 module
Only have the time of day of the station from an external time source synchronized by a
single module so that a consistent time of day is maintained within the station.
When the CPU takes the time from the CP, disable time-of-day synchronization of the CPU.
Procedure for time-of-day synchronization with the CP
The CP supports the two methods of time-of-day synchronization:
● Time from partner
The time of the CP is synchronized by a telecontrol server.
Only with communication type "Telecontrol" activated.
● NTP / NTP (secure)
Only with communication type "Telecontrol" deactivated.
The method NTP (secure) can only be selected if the security functions are enabled.
Recommendation for setting the time: Synchronization with a external clock at intervals of
approximately 10 seconds is recommended. This achieves as small a deviation as
possible between the internal time and the absolute time.
Configuration with the CP
Selection of the synchronization method
Depending on the configured communication types and security functions, time-of-day
synchronization is configured differently:
● Telecontrol communication enabled
With telecontrol communication enabled, the time of day of the CP is synchronized
automatically by the TCSB computer.
– Security functions enabled:
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The time-of-day synchronization is configured in the "Security" parameter group.
Operating Instructions, 10/2016, C79000-G8976-C311-02
CP 1242-7 GPRS V2