Accessing the RTC special data registers

In this example the system variables of the real time clock are called in structured text. The numbers of data registers differ for the PLC type used.

System variable	FP0, FPe	FPS, FP-X, FP2, FP2SH
`sys_wClockCalendarMinSec`	DT9054	DT90054
`sys_wClockCalendarDayHour`	DT9055	DT90055
`sys_wClockCalendarYearMonth`	DT9056	DT90056
`sys_wClockCalendarSet`	DT9058	DT90058

POU header

In the POU header, all input and output variables are declared that are used for programming this function.

ST body

(* Set RTC to 05-06-31 12:00:00 *)

if (bSetNewRTC) then

    sys_wClockCalendarMinSec:=16#0000;

    sys_wClockCalendarDayHour:=16#3112;

    sys_wClockCalendarYearMonth:=16#0506;

    sys_wClockCalendarSet:=16#8000;

end_if;

(* Evaluate the RTC for 12:00:00 *)

if ( sys_wClockCalendarMinSec=16#0000AND

    (sys_wClockCalendarDayHour AND16#00FF)=16#0012) then

    (* React on lunch time *)

end_if;