Hi StalinCode,

The WinCC Unified system typically uses the Network Time Protocol (NTP) to synchronize time. However, when connecting to an S7-1200 or S7-1500, time can be written from the HMI device to the PLC using the "SetPLCDateTime" method.

To ensure continuous synchronization between the HMI and the PLC, it is preferable to configure the PLC as an NTP server using the LSNTP function in the Libraries for Communication for SIMATIC Controllers.

Kind regards
Stefan