Siemens SIMATIC TeleControl DNP3 Configuration Manual page 69

Methods for receiving the time of day
● NTP / NTP (secure)
Network Time Protocol
Time-of-day synchronization only via Ethernet
The secure method NTP (secure) uses authentication with symmetrical keys. Various
configurable hash algorithms are available for the integrity check.
In the global security settings, you can create and manage NTP servers of the type
NTP (secure).
Recommendation wit NTP:
Synchronization with an external clock at intervals of approximately 10 seconds is
recommended. This achieves as small a deviation as possible between the internal time
and the UTC time.
Note on the TIM 1531 IRC:
When an FQDN is used as address of the NTP server, up to 240 characters can be
entered.
● From WAN (TIM)
The TIM adopts the time of day from a subscriber in the connected network.
The following can be time masters:
– A synchronized CPU
– A subscriber with a time receiver
– A master station PC connected to the Ethernet network
● Time from partner (CP 1243-1 / CP 1243-8 IRC)
The CP adopts the time-of-day from the communications partner in the master station.
● Time from CPU (CP 1243-1 / CP 1243-8 IRC)
As of V4.2, the CPU 1200 synchronizes all CMs/CPs of the station with a synchronization
cycle of 10 seconds.
Parameters of the CPU:
If the option "CPU synchronizes the modules of the device" is enabled, you can initiate
synchronization of all telecontrol CPs of the station with firmware ≥ V2.1.77 with the CPU
time in a synchronization cycle of 10 seconds.
● Setting the time of day manually using the WBM (TIM 1531 IRC)
If you have configured a time source for the TIM, you can also set the time via the WBM,
see section System time (Page 172).
Configuration - DNP3
Configuration Manual, 11/2018, C79000-G8976-C508-01
Configuration
3.13 Time-of-day synchronization
69