Create Variables

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• As a naming convention for variables, it is recommended to use the initial to reflect the variable type
  (e.g. Boolean with b; long integer with L)

Use the Dictionary

For explanations on dictionary usage, including how to create and rename variables, Dictionary Contextual Menu

Create Variables from the Editors

You can create variables directly from the IEC"International Electrotechnical Commission" IEC is a not-for-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies 61131-3 editors, as follows:

FBD"Function block diagram" A function block diagram describes a function between input variables and output variables. A function is described as a set of elementary blocks editor

1. Click the dedicated button
   

Figure 4-82: Add Variable in FBD Editor

2. Click a location in the editor (or double-click the variable if it is already created)
3. Edit the name in the Variable Editor (or select an existing variable within the list which is already filtered according to their relevant data type)
   

Figure 4-83: Define Variable Name in FBD Editor

4. The KAS IDE"Integrated development environment" An integrated development environment is a type of computer software that assists computer programmers in developing software. IDEs normally consist of a source code editor, a compiler and/or interpreter, build-automation tools, and a debugger automatically checks if the variable already exists. If it is new, you have to:
• Select its type in the drop-down menu: for FBD and FFLD, it is set by default according to the In or Out data type of the function block
• Specify where it is defined: the default is the current PLC"Programmable Logic Controller" A Programmable Logic Controller, PLC, or Programmable Controller is a digital computer used for automation of industrial processes, such as control of machinery on factory assembly lines. Used to synchronize the flow of inputs from (physical) sensors and events with the flow of outputs to actuators and events program, but you can choose to make the variable Global or declared as a retain variable



Figure 4-84: Define Variable Type in FBD Editor

FBD variables

FFLD editor

1. Double-click the in or out pins of the function block
   

Figure 4-85: Add a Variable in the FFLD Editor

2. Edit the name (or select an existing variable within the list which is already filtered according to their relevant data type)
   

Figure 4-86: Define a Variable Name in the FFLD Editor

3. The KAS IDE automatically checks if the variable already exists. If it is new, you have to:
• Select its type in the drop-down menu (by default, it is set according to the In or Out data type of the function block)
• Specify where it is defined
  

Figure 4-87: Define a Variable Type in the FFLD Editor

Data Types

You can create a variable of available Data Types.

For a list of types, List of Data types

Arrays

Complex Structures

Complex variables are arrays, structures, and instances of function blocks. The following features are allowed for programming:

• Use arrays of structures
• Use arrays of FB instances
• Pass any complex data (array, structure, instance) to a UDFB"User Defined Function Block" UDFB can be used as a sub-function block in another program of the application. It is described using FBD, LD, ST or IL language. Input / output parameters of a UDFB (as well as private variables) are declared in the variable editor as local variables of the UDFB or sub-program

There is almost no limitation in the amount of complex data declared (theoretically up to 4GB, but practically limited by the memory available in the runtimeIn computer science, runtime (or run-time) describes the operation of a computer program, the duration of its execution, from beginning to termination (compare compile time). Within KAS, runtime also refers to the virtual machine that manage the program written in a computer language while it is running)

For more explanations on the Structure concept, refer to Structures

Declare the structure

1. Right-click in the Dictionary to open the menu
2. Select the Add structure command
   

Figure 4-89: Add a Complex Structure

3. Right-click on the newly created structure and select the Rename structure command
   

Figure 4-90: Rename Complex Structure

4. Right-click on the new structure and select the Add variable command
   

Figure 4-91: Add Variable to a Complex Structure

5. Expand the new structure
6. Double-click on the new nested variable and define its name and type
   
7. Repeat steps 5 and 7 to add all the requested variables

Create an instance of the structure

When finalized, you can drag-and-drop the structure from the library in the (Project) node to a program just like any other function block. A new instance is automatically created.

1. Select the new structure and move it with a drag-and-drop operation to the program declaration within the Dictionary
   

Figure 4-92: Create an Instance of the Structure

2. You can also add a variable in the Dictionary with the Add variable command. Then double-click on the new variable to define its type by selecting the structure type which is displayed in the Type drop-down menu.
   
3. Then you can drag this new instance and drop it in your program like any other variable

See Also