Siemens Simatic RTU303xC Series Operating Instructions Manual page 119

The system time set here is kept by the internal clock of the RTU. For information on the
accuracy, see section Technical data (Page 335).
● New system time
Here, enter the current time of day manually.
When making your entry, keep to the specified format.
Month, day, and hour can also be entered as single digits. Example: March is accepted
as "03" or as "3".
If you click the Apply new time of day button the RTU adopts the entered time of day.
● Adopt PC time
If you click the Adopt PC time button the RTU adopts the time of day from the
configuration PC.
Time-of-day format and time stamps
System time of the RTU
The RTU keeps its time-of-day as UTC. The time of day and includes the time difference
since 01.01.1970 in milliseconds.
The RTU can reach the local time via the information on local time in the "System time" tab
and use it, for example, for the messages from the diagnostics buffer and in the WBM.
Time stamp of the data frames
If the communications services are activated, the time stamps of the data frames are
transferred depending on the protocol being used:
● TeleControl Basic
Transfer of the time stamps in UTC format (48 bits)
● ST7
Refer to the information on time stamps in the manual of the communications partner. In
the configuration, the transfer of either the local time or UTC time can be set.
● DNP3
Transfer of the time stamps in UTC format (48 bits)
● IEC 60870-5
Transfer of the time stamps in the "CP56Time2a" format. In the configuration, the transfer
of either the local time or UTC time can be set.
Keep to the recommended settings in the note above.
RTU303xC
Operating Instructions, 06/2019, C79000-G8976-C382-06
Configuration (WBM)
4.10 System
119