SUPER¶

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

Note

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;

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;