Naming a variable

To change the name of the variable, enable the modification mode in the grid and move the cursor to the selected "name" cell. Then press ENTER or hit the first character of the new name. Name is entered in a small box. Hit ENTER to validate the name or ESCAPE to cancel the change.

A variable must be identified by a unique name within its parent group. The variable name cannot be a reserved keyword of the programming languages and cannot have the same name as a standard or "C" function or function block. A variable should not have the same name as a program or a user defined function block.

The name of a variable should begin by a letter or an underscore ("_") mark, followed by letters, digits or underscore marks. It is not allowed to put two consecutive underscores within a varable name. Naming is case insensitive. Two names with different cases are consiidered as the same.

Naming Physical I/Os

Each I/O channel as a predefined symbol that reflects its physical location. This symbol begins with "%I" for an input and "%Q" for an output, followed by a letter identifying the physical size of the data. Refer to the description of variables for more details.

You cannot change the "%..." name of an I/O variable. This name is directly allocated according to the I/O devices defined in the I/O device list. But you can give an alias (a readable name) to each I/O channel. In that case, either the "%" name or the alias can be used in programs with no difference. The alias must fit to the same rules as a variable name.

When an alias is defined for a variable, both "%..." name and alias are displayed in the "name" column of the grid.