SUPER
is a special variable and is used for object-oriented programming.
SUPER
is the pointer of a function block to the basic function block instance from which
the function block was generated. The SUPER
pointer thus also permits access to the implementation of the methods of the basic
function block (basic class). A SUPER
pointer is automatically available for each function block.
You can use SUPER
only in methods and in the associated function block implementations.
Dereferencing of the pointer: SUPER^
Use of the SUPER
pointer: with the help of the keyword SUPER
you call a method that is valid in the instance of the basic class or parent class.
Examples
ST:
SUPER^.METH_DoIt();
FBD/CFC/LD

THIS
is not yet implemented for the instruction list (IL).
Examples
Use of SUPER
and THIS
pointers
FUNCTION_BLOCK FB_Base VAR_OUTPUT iCnt : INT; END_VAR METHOD METH_DoIt : BOOL iCnt := -1; METHOD METH_DoAlso : BOOL METH_DoAlso := TRUE; FUNCTION_BLOCK FB_1 EXTENDS FB_Base VAR_OUTPUT iBase : INT; END_VAR THIS^.METH_DoIt(); //Call of the methods of FB_1 THIS^.METH_DoAlso(); SUPER^.METH_DoIt(); //Call of the methods of FB_Base SUPER^.METH_DoAlso(); iBase := SUPER^.iCnt; METHOD METH_DoIt : BOOL iCnt := 1111; METH_DoIt := TRUE; PROGRAM PLC_PRG VAR myBase : FB_Base; myFB_1 : FB_1; iTHIS : INT; iBase : INT; END_VAR myBase(); iBase := myBase.iCnt; myFB_1(); iTHIS := myFB_1.iCnt;
See also