ST_BACnet_DateTime

PLC mapping of BACnet data type BACnetDateTime. See BACnet specification DIN EN ISO 16484-5 for data type BACnetDateTime.

TYPE ST_BACnet_DateTime :
STRUCT
  stDate  : ST_BACnet_Date;
  stTime  : ST_BACnet_Time;
END_STRUCT
END_TYPE

Warning:

If BACnetDateTime values are used for switching in schedules, for example, the following exemplary switching times should be avoided:

Mo. 0:00.00 - ACTIVE → Mo. 23:59.59 - INACTIVE

Reason: Switching to state INACTIVE may not be detected. The switching time is immediately prior to the day switching. In this example, if the day changes from Monday to Tuesday before the time change from 23:59.58 to 23:59.59 is detected, the entry for Monday 23:59.59 to INACTIVE is no longer executed. This effect may occur in controllers with high load, or if moderate BACnet cycle times are used (>> 100 ms).

To set switching periods covering a whole day (24 hrs), the following switching times should be used instead:

Mo. 0:00.00 - ACTIVE → Tu. 0:00.00 - INACTIVE

or (e.g. 5 minutes to midnight):

Mo. 0:00.00 - ACTIVE → Mo. 23:55.00 - INACTIVE