SA0012: Variables which could be declared as constants

Function	Determines variables that are not subject to write access and therefore could not be declared as constants.
Reason	If a variable is only written at the declaration point and is otherwise only used in read mode, the static analysis assumes that the variable is to remain unchanged. Declaration as a constant means that the variable is checked for changes in the event of program modifications. Plus, declaration as a constant may lead to faster code.
Importance	Low

Sample:

PROGRAM MAIN 
VAR
    nSample  : INT := INT#17;
    nVar     : INT; 
END_VAR

nVar := nVar + nSample;          // => SA0012