Security > "Time-Of-Day Synchronization - Siemens SIMATIC S7-400 Operating Instructions Manual

Configuration and operation
4.8 Configuration of the CP in STEP 7 Professional
● S7 communication
● Certificate manager
Via the local certificate manager, you can import and export certificates for the CP.
You will find help on the certificate manager in the STEP 7 information system ate
following location:
> Industrial Ethernet Security > Configuring security > General > Managing certificates"
4.8.7 Security > "Time-of-day synchronization"
Synchronization method
Note
Recommendation for setting the time
If the infrastructure of your project allows, 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.
if the security functions are enabled, the CP supports the following methods of time-of-day
synchronization:
● SIMATIC mode
The SIMATIC mode cannot be configured.
If you leave the time-of-day synchronization via NTP disabled, the SIMATIC mode is
enabled automatically on the CP. In this case, the CP can only adopt the time of day from
the station.
Note that with the CP as OPC UA server when using the SIMATIC mode the time is not
displayed as UTC but as the local time of the station.
● NTP
If the option is enabled and the Security functions disabled, the CP synchronizes its time
of day via NTP.
When NTP is enabled, the CP as OPC UA server displays the time of day in the UTC
format.
You configure the synchronization method, the local time zone of the station, the
synchronization interval and the addresses of the NTP servers.
● NTP (secure)
If the Security functions are enabled, the time of day can be synchronized using
NTP (secure),
The secure method NTP (secure) uses authentication with symmetrical keys according to
the hash algorithms MD5 or SHA-1.
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"Editing devices and networks >Configuring devices and networks >Configure networks
Operating Instructions, 01/2017, C79000-G8976-C427-02
CP 443-1 OPC UA