Variable names

In straton variable names must be in accordance with the IEC 61131-3 regulations. The correctness of the entry is checked by zenon as well as by straton (communication take place using the STRATON32 driver).

For variables of other drivers (e.g. S7 TCO/IP driver), the engineer has to check that the variable name fulfills the regulations of the IEC 61131-3 (communication takes place using shared memory).

Examples for the IEC 61131-3 notation

Permitted name	Impermissible name	Comment
_XYZ	__XYZ	Twice with Underscore
xy_z	xy__z	Twice with Underscore
xyz_	xyz__	Twice with Underscore
MotorOn	Motor On	space
Motor_On	Motor On	Slash
mw10	1mw10	Numeral/ number at the beginning
xyz	#xyz	Hash
_Motor1	_Motor 1	space
Disturbance	Disturbance	Umlaut/diphthong
Bridge	Bridge	Umlaut/diphthong
Mo_tor	Mo-tor	hyphen

Now it it possible to use variables which are following the IEC 61131-3 regulations (free variable names). Take care when using free variable names.

Follow these rules when using free variable names:

The following characters are not allowed to be part of a variable name: '(*', '*)', '//', '{' and '}'
Variable names are not allowed to start with '__' (two underscores)
If free variable names are used when using programming language ST or IL, they must be between {}.
If free variable names are used with structure of array, they must be between {}.
Variables with free variable names with a basis data type can be used without {} in programming languages FBD and LD. They must be declared as global variables.
Variables with the same name once with {} and once without {} are regarded as two different variables.