Detects variables with names that are already used by other variables (for example, global and local variables with the same name). Also detects variables with names of functions, actions, methods, or properties which are used in the same access scope. Variables are also detected that are declared in a GVL in the “Devices” view or in the POUs pool. For this, however, the GVL of the “POUs” view have to be used in the application program.
Justification: The same names can be confusing when reading the code, and they can cause errors if the wrong object is accessed unintentionally. We recommend that you use naming conventions to avoid these situations.
PLCopen rule: N5 / N9
Importance: Medium
Example
VAR_GLOBAL xVar1 : BOOL; iVar3 : INT; END_VAR PROGRAM PLC_PRG VAR xVar1 : BOOL; // SA0013 iVar3 : INT; // SA0013 END_VAR xVar1 := NOT GVL.xVar1; iVar3 := iVar3 + INT#2; iVar3 := GVL.iVar3; --> SA0013: Declaration of 'iVar1' hides symbol 'GVL.iVar1 --> SA0013: Declaration of 'xVar3' hides symbol 'GVL.xVar3
Example
The function block POU has the action ACT and the method METH.
FUNCTION_BLOCK POU VAR ACT : UINT; // SA0013 METH : BYTE; // SA0013 END_VAR --> SA0013: Declaration of 'ACT' hides symbol 'POT.ACT' --> SA0013: Declaration of 'METH' hides symbol 'POT.METH'