SA0102: Access to program/fb variables from the outside

Detects external access to local variables of programs or function blocks.

Justification: CODESYS permits external read access to local variables of programs or function blocks. This contradicts the principle of data encapsulation (hiding data) and does not comply with the IEC 61131-3 standard.

Importance: Medium

Example 91. Example

PROGRAM PLC_PRG
VAR
        iCounter : INT;
        afb_Instance : AFB;
        bfb_Instance : BFB;
END_VAR

iCounter := A_PRG.iLocal;                               //  SA0102
iCounter := bfb_Instance.iLocal;                 //  SA0102
A_PRG();

FUNCTION_BLOCK AFB
VAR_INPUT
END_VAR
VAR_OUTPUT
END_VAR
VAR
        iLocal: INT;
END_VAR

METHOD METH : INT
VAR_INPUT
END_VAR

iLocal := iLocal + 1;

FUNCTION_BLOCK BFB EXTENDS AFB
VAR_INPUT
END_VAR
VAR_OUTPUT
END_VAR
VAR
END_VAR
METHOD METH : INT
VAR_INPUT
END_VAR

iLocal := iLocal + 1;

PROGRAM A_PRG
VAR
        iLocal: INT;
END_VAR

iLocal := iLocal + 1;

Output in the Messages view:

SA0102: Access to program/fb variable 'iLocal' from the outside