A string constant is a character string enclosed in single straight quotation marks. The characters are coded according to the character set specified in ISO/IEC 8859-1. Therefore, a string constant can include spaces and accented characters, as these belong to this character set. This is also referred to as a string literal, or simply a string.

Example: ‎'Hello world!'‎

When a dollar sign ($) is in a string constant, the following two characters are interpreted as a hexadecimal code according to the coding in ISO/IEC 8859-1. The code also corresponds to ASCII code. In addition, please note the special cases.

VAR CONSTANT 
	constA : STRING := 'Hello world';
	constB : STRING := 'Hello world $21'; // Hello world!
END_VAR