1) WR_SYS_T (write system time) writes the DTL value of the input IN to the PLC real time clock.
SIEMENS PLC set up system time
There are two ways to set PLC time and real-time time synchronization.
1. In SIMATIC Manager, open the project in turn to the CPU (such as CPU 315-2DP), then right-click the CPU to select “PLC/Set Time of Day”, set the corresponding time in the interface, directly modify the CPU time and date;
2. You can also open your project in SIMATIC Manager and select the menu PLC/Diagnostic/Setting/Setting Time of Day (Diagnosis/Setting/Setting Date Time of Day). In the open interface, you can change the date of the CPU with the same settings as above.