Siemens S7-1200 TELECONTROL Operating Instructions Manual page 47

● Telecontrol communication not enabled
The time of day of the CP can only be synchronized with NTP mechanisms:
– Security functions enabled:
– Security functions not enabled:
Parameter
● NTP (secure) with security functions enabled
If you use Security functions, a valid time of day is extremely important. It is
recommended to use the NTP (secure) method.
The secure method NTP (secure) uses authentication with symmetrical keys according to
the hash algorithms MD5 or SHA-1.
You can create and manage additional NTP servers also of the type NTP (secure) in the
global Security settings of the STEP 7 project.
● "Accept time from non-synchronized NTP servers" option
If the option is enabled, the CP also accepts the time-of-day from non-synchronized NTP
servers with stratum 16.
If the option is disabled, 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".
For more information on configuration, refer to the STEP 7 online help of the "Time
synchronization" parameter group.
Time-of-day synchronization of the CPU
As the synchronization method, with the CPU only NTP can be selected.
If for the CPU the option "CPU synchronizes the modules of the device" is enabled, all smart
modules of the station (CMs, CPs) are synchronized with the CPU time in a synchronization
cycle of 10 seconds.
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.
CP 1242-7 GPRS V2
Operating Instructions, 10/2016, C79000-G8976-C311-02
The time-of-day synchronization is configured in the "Security" parameter group. NTP
and NTP (secure) are available as the synchronization methods.
The time-of-day synchronization is configured in the "Ethernet interface > Time
synchronization" parameter group. Only NTP is available as the synchronization
method.
Configuration and operation
4.8 Time-of-day synchronization
47