Declaration of Variables

At a Glance

All of the variables used in the different sections of the program must be declared.

Undeclared variables cannot be used in the program.

NOTE: For more information, refer to chapter Data Editor.

Procedure for Declaring Variables

The table below shows the procedure for declaring application variables.

Step	Action
1	In Project browser / Variables & FB instances, double-click on Elementary variables
2	In the Data editor window, select the box in the Name column and enter a name for your first variable.
3	Now select a Type for this variable.
4	When all your variables are declared, you can close the window.

Variables Used for the Application

The following table shows the details of the variables used in the application.

Variable	Type	Definition
Run	EBOOL	Startup request for the labelling process.
Stop	EBOOL	Stop the labelling process.
Last_Box_late	BOOL	The process is in deflection.
Nb_Box	DINT	Number of labelled boxes.
Position_0	BOOL	Box at the beginning of the conveyor.
Position_1	BOOL	Box with the first label.
Position_2	BOOL	Box with the two labels.
First_Labelling_Point	DINT	Lower Threshold value.
Second_Labelling_Point	DINT	Upper Threshold value.
Deflection_Parameter	DINT	Deflection alarm triggering value.
Waiting_First_Part	BOOL	The first box is waited.
Waiting_Other_Parts	BOOL	The first box has already passed.

The following screen shows the application variables created using the data editor :

NOTE: Click on

in front of the derived variable Encoder to expand the I/O objects list.