Time-Of-Day Synchronization - Siemens SIMATIC NET TeleControl S7-1200 CP 1243-1 Operating Instructions Manual

Configuration
4.8 Security
4. Now select the CP in the S7 station.
5. Enable the advanced firewall mode in the local security settings of the CP in the "Security
> Firewall" parameter group.
6. Open the "IP rules" parameter group.
7. In the table, insert a new IP rule for the previously created global services as follows:
– Action: Allow; "From external -> To station " with the globally created "Echo request"
– Action: Allow; "From station -> to external" with the globally created "Echo reply"
8. For the IP rule for the Echo Request, enter the IP address of the engineering station in
"Source IP address". This ensures that only ICMP frames (ping) from your engineering
station can pass through the firewall.
4.8.4

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 and security functions activated.
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.
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service
service
Operating Instructions, 12/2016, C79000-G8976-C365-02
CP 1243-1