Configuration, programming
4.5 Time-of-day synchronization
CP 1543-1
Operating Instructions, 12/2019, C79000-G8976-C289-08
41
4.5
Time-of-day synchronization
General rules
The CP supports the following mode for timeofday synchronization:
●
NTP mode (NTP: Network Time Protocol)
Note
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.
Note
Special feature of time-of-day synchronization using NTP
If the option "Accept time from non-synchronized NTP servers" is not selected, the
response is as follows:
If the CP receives a time-of-day frame from an unsynchronized NTP server with stratum
16, the time of day is not set according to the frame. In this case, none of the NTP
servers is displayed as "NTP master" in the diagnostics; but rather only as being
"reachable".
Security
In the extended NTP configuration, you can create and manage additional NTP servers.
Note
Ensuring a valid time of day
If you use security functions, a valid time of day is extremely important. If you do not obtain
the time-of-day from the station (CPU), we therefore recommend that you use the
NTP (secure) method.
Configuration
For more detailed information on configuration, refer to the STEP 7 online help of the "Time-
of-day synchronization" parameter group.