Snap7-based example of retrieving the date and time from a DTL-field, DATE-field, or TOD-field (time of day). Tested on a Siemens 1214C PLC.

snap7-get-date-time.py

import datetime
import snap7
from snap7.util import *

class DtlExample:
    def __init__(self, ip, db):
        self.plc = snap7.client.Client()
        self.ip = ip
        self.db = db

    def connect(self):
        self.plc.connect(self.ip, 0, 0)

    def db_read(self, offset, length):
        return self.plc.db_read(self.db, offset, length)

    def disconnect(self):
        self.plc.disconnect()
        
    def get_date(self, offset):
        date = datetime.datetime(1990, 1, 1)
        return date + datetime.timedelta(get_int(self.db_read(offset, 2)[0:2], 0))

    def get_dtl(self, offset):
        dtl = self.db_read(offset, 12)
        return datetime.datetime(get_int(dtl, 0), ord(dtl[2:3]), ord(dtl[3:4]), ord(dtl[5:6]), ord(dtl[6:7]),
                                 ord(dtl[7:8]), get_dword(dtl, 8)/1000)
    
    def get_time_of_day(self, offset):
        now = datetime.datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
        return now + datetime.timedelta(milliseconds=self.get_dword(offset))