SetRTCDrift: Adjust the Real Time Clock Each Week

Function Description

This function adds or subtracts to the Real Time Clock (RTC) a specified number of seconds, each week, at the specified day of the week and time (hour:minute).

NOTE: The SetRTCDrift function needs to be programmed to be executed only during the First Mast Cycle.

Graphical Representation

IL and ST Representation

To see the general representation in IL or ST language, refer to the chapter Function and Function Block Representation.

I/O Variables Description

This table describes the input parameters:

Inputs	Type	Comment
RtcDrift	SINT(-29...+29)	Correction in seconds (-29 ... +29)
Day	DAY_OF_WEEK	Day of change.
Hour	HOUR	Hour of change.
Minute	MINUTE	Minute of change.

NOTE: If the values entered for RTCDrift, Day, Hour, Minute exceed the limit values, the logic controller firmware sets all values to their maximum values.

This table describes the output variable:

Output	Type	Comment
SetRTCDrift	RTCSETDRIFT_ERROR	Returns RTC_OK (00 hex) if command is correct otherwise returns the ID code of the detected error.

Example

In this example, the function is called only once during the first MAST task cycle and 20 seconds is added to the RTC every Tuesday at 5:45

VAR
   MyRTCDrift : SINT (-29...+29) := 0;
   MyDay : DAY_OF_WEEK;
   MyHour : HOUR;
   MyMinute : MINUTE;
END_VAR

IF IsFirstMastCycle() THEN
   MyRTCDrift := 20;
   MyDay := TUESDAY;
   MyHour := 5;
   MyMinute := 45;
   SetRTCDrift(MyRTCDrift, MyDay, MyHour, MyMinute);
END_IF