Variable forcing now uses limited list and buffer instead of systematical instance tree traversal and in-tree "fvalue" to keep track of forced value for pointed variables (external, located). Pointer swapping is performed when forcing externals and located, with backup being restored when forcing is reset. Match Beremiz commit 93ad018fb602.
(****************************************************************
RTC - Real-time clock
Q is a copy of IN.
When IN = FALSE, CDT is the current date and time as set by the
PLC driver.
When IN changes from FALSE to TRUE, PDT is stored. As long as IN is
TRUE, CDT is equal to PDT + the amount of time since PDT was loaded.
****************************************************************)
FUNCTION_BLOCK RTC
VAR_INPUT
IN : BOOL; (* 0 - current time, 1 - load time from
PDT *)
PDT : DT; (* Preset datetime *)
END_VAR
VAR_OUTPUT
Q : BOOL := FALSE; (* Copy of IN *)
CDT : DT; (* Datetime, current or relative to PDT *)
END_VAR
VAR
PREV_IN : BOOL := FALSE;
OFFSET : TIME;
CURRENT_TIME : DT;
END_VAR
{__SET_VAR(data__->,CURRENT_TIME,,__CURRENT_TIME)}
IF IN
THEN
IF NOT PREV_IN
THEN
OFFSET := PDT - CURRENT_TIME;
END_IF;
(* PDT + time since PDT was loaded *)
CDT := CURRENT_TIME + OFFSET;
ELSE
CDT := CURRENT_TIME;
END_IF;
Q := IN;
PREV_IN := IN;
END_FUNCTION_BLOCK