Constants pour affichage CoDeSys

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.

Hexadecimal code

String with $ code	Interpretation
‘$<8-bit code>’	8-bit code: Two-digit hexadecimal number that is interpreted according to ISO/IEC 8859-1.
‘$41’	A
‘$A9’	©
‘$40’	@
‘$0D’	Control character: Line break (corresponds to ‘$R’)
‘$0A’	Control character: New line (corresponds to ‘$L’ and ‘$N’)

Special cases

String with $ code	Interpretation
‘$L’, ‘ $l’	Control character: Line feed (corresponds to ‘$0A’)
‘$N’, ‘$n’	Control character: New line (corresponds to ‘$0A’)
‘$P’, ‘$p’	Control character: Form feed
‘$R’, ‘$r’	Control character: Line break (corresponds to ‘$0D’)
‘$T’, ‘$t’	Control character: Tab
‘$$’	Dollar sign: §
‘$”	Single straight quotation mark: ‘

Example

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

Retour curseur et saut de ligne : ‘$R$L’ ou ‘$0D$0A’