Name a variable

To change the name of the variable, do as follows:

  1. In the Name column of the table, select the cell you want to edit
  2. Press ENTER (or press the first character of the new name)
  3. Enter the name in the small box
  4. Press 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 must not have the same name as a program or a user-defined FunctionClosedA function calculates a result according to the current value of its inputs. A function has no internal data and is not linked to declared instances. Block.

The name of a variable must 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 variable name. Naming is case-insensitive. Two names with different cases are considered as the same.

Naming Physical I/Os

Each I/O channel has 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. 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.