Declaration Editor...

It is available in the context menu (<F2>) or in the 'Extras' menu, if the cursor is positioned on the name of a function block in a text editor or if the function block box is selected in a graphic editor.

Intellisense Function

If the option List components is activated in the project options dialog for category 'Editor' , then the "Intellisense" functionality will be available in all editors, in the Watchand Receiptmanager, in the Visualization and in the Sampling Trace:

•If you insert a dot "." instead of an identifier, a selection box will appear, listing all local and global variables of the project. You can choose one of these elements and press 'Return' to insert it behind the dot. You can also insert the element by a double-click on the list entry.

•If you enter a function block instance or a structure variable followed by a dot, then a selection box listing all input and output variables of the corresponding function block resp. listing the structure components will appear, where you can choose the desired element and enter it by pressing 'Return' or by a double-click.

Example:

Insert "struvar." -> the components of structure struct1 will be offered:

5.2Declaration Editor...

5.2.1Working in the Declaration Editor

The declaration editor is used to declare variables of POUs and global variables, for data type declarations, and in the Watch and Receipt Manager. It gives access to the usual Windows functions, and even those of the IntelliMouse can be used if the corresponding driver is installed.

In Overwrite mode, 'OV' is shown in black on the status bar; switching between Overwrite and Insert modes can be accomplished with the <Ins> key.

The declaration of variables is supported by syntax coloring.

The most important commands are found in the context menu (right mouse button or <Ctrl>+<F10>).

Declaration Part

All variables to be used only in this POU are declared in the declaration part of the POU. These can include: input variables, output variables, input/output variables, local variables, remanent variables and constants. The declaration syntax is based on the IEC61131-3 standard.

Regard the possibility of using templates for objects of type 'Global Variables', 'Data types', 'Function', 'Function Block' or 'Program' , see Chapter 4.3, 'File' New from template'.

An example of a correct declaration of variables in CoDeSys-Editor:

5 - Editors in CoDeSys

Input Variable

Between the key words VAR_INPUT and END_VAR, all variables are declared that serve as input variables for a POU. That means that at the call position, the value of the variables can be given along with a call.

Example:

VAR_INPUT

in1:INT (* 1. Inputvariable*) END_VAR

Output Variable

Between the key words VAR_OUTPUT and END_VAR, all variables are declared that serve as output variables of a POU. That means that these values are carried back to the POU making the call. There they can be answered and used further.

Example:

VAR_OUTPUT

out1:INT; (* 1. Outputvariable*)

END_VAR

Input and Output Variables

Between the key words VAR_IN_OUT and END_VAR, all variables are declared that serve as input and output variables for a POU.

Attention: With this variable, the value of the transferred variable is changed ("transferred as a pointer", Call-by- Reference). That means that the input value for such variables cannot be a constant. For this reason, even the VAR_IN_OUT variables of a function block can not be read or written directly from outside via <functionblockinstance><in/outputvariable>.

Example:

VAR_IN_OUT

inout1:INT; (* 1. Inputoutputvariable *)

END_VAR

Local Variables

Between the keywords VAR and END_VAR, all of the local variables of a POU are declared. These have no external connection; in other words, they can not be written from the outside.

Example:

VAR

Declaration Editor...

loc1:INT; (* 1. Local Variable*) END_VAR

Remanent variables

Remanent variables can retain their value throughout the usual program run period. These include Retain variables and Persistent variables.

Example:

VAR RETAIN

rem1:INT; (* 1. Retain variable*)

END_VAR

•Retain variables are identified by the keyword RETAIN. These variables maintain their value even after an uncontrolled shutdown of the controller as well as after a normal switch off and on of the controller (resp. at the command 'Online' 'Reset', see Chapter 4.6). When the program is run again, the stored values will be processed further. A concrete example would be an piece-counter in a production line, that recommences counting after a power failure.

All other variables are newly initialized, either with their initialized values or with the standard initializations.

Contrary to Persistent variables Retain Variables are reinitialized at a new download of the program.

•Persistent variables are identified by the keyword PERSISTENT. Unlike Retain variables, these variables retain their value only after a re-Download, but not after an 'Online' 'Reset', 'Online' 'Reset (original)' or 'Online' 'Reset (cold)' (see Chapter 4.6 each), because they are not saved in the "retain area". If also persistent variables should maintain their values after a uncontrolled shutdown of the controller, then they have to be declared additionally as VAR RETAIN variables. A concrete example of "persistent Retain-Variables" would be a operations timer that recommences timing after a power failure.

Attention:

•If a local variable in a program is declared as VAR RETAIN, then exactly that variable will be saved in the retain area (like a global retain variable)

•If a local variable in a function block is declared as VAR RETAIN, then the complete instance of the function block will be saved in the retain area (all data of the POU), whereby only the declared retain variable will be handled as a retain.

•If a local variable in a function is declared as VAR RETAIN, then this will be without any effect. The variable will not be saved in the retain area! If a local variable is declared as PERSISTENT in a function, then this will be without any effect also!

Constants, Typed Literals

Constants are identified by the key word CONSTANT. They can be declared locally or globally. Syntax:

VAR CONSTANT <Identifier>:<Type> := <initialization>; END_VAR

5 - Editors in CoDeSys

Example:

VAR CONSTANT

con1:INT:=12; (* 1. Constant*)

END_VAR

See Appendix B: Operands in CoDeSys, for a listing of possible constants. See there also regarding the possibility of using typed constants (Typed Literals).

External variables

Global variables which are to be imported into the POU are designated with the keyword EXTERNAL. They also appear in the Watch window of the declaration part in Online mode.

If the VAR_EXTERNAL declaration does not match the global declaration in every respect, the following error message appears: "Declaration of '<var>' does not match global declaration!"

If the global variable does not exist, the following error message appears: "Unknown global variable: '<var>'!"

Example:

VAR EXTERNAL

var_ext1:INT:=12; (* 1st external variable *)

END_VAR

Keywords

Keywords are to be written in uppercase letters in all editors. Keywords may not be used as variables. Examples for keywords: VAR, VAR_CONSTANT, IF, NOT, INT.

Variables declaration

A variables declaration has the following syntax: <Identifier> {AT <Address>}:<Type> {:=<initialization>}; The parts in the braces {} are optional.

Regarding the identifier, that is the name of a variable, it should be noted that it may not contain spaces or umlaut characters, it may not be declared in duplicate and may not be identical to any keyword. Upper/lowercase writing of variables is ignored, in other words VAR1, Var1 and var1 are not different variables. Underlines in identifiers are meaningful, e.g. A_BCD and AB_CD are interpreted as different identifiers. Multiple consecutive underlines at the beginning of an identifier or within a identifier are not allowed. The length of the identifier, as well as the meaningful part of it, is unlimited.

All declarations of variables and data type elements can include initialization. They are brought about by the ":=" operator. For variables of elementary types, these initializations are constants. The defaultinitialization is 0 for all declarations.

Example:

var1:INT:=12; (* Integer variable with initial value of 12*)

If you wish to link a variable directly to a definite address, then you must declare the variable with the keyword AT.

For faster input of the declarations, use the shortcut mode.

In function blocks you can also specify variables with incomplete address statements. In order for such a variable to be used in a local instance, there must be an entry for it in the variable configuration.

Pay attention to the possibility of an automatic declaration

Declaration Editor...

AT Declaration

If you wish to link a variable directly to a definite address, then you must declare the variable with the keyword AT. The advantage of such a procedure is that you can assign a meaningful name to an address, and that any necessary changes of an incoming or outgoing signal will only have to be made in one place (e.g., in the declaration).

Notice that variables requiring an input cannot be accessed by writing.

Examples:

counter_heat7 AT %QX0.0: BOOL; lightcabinetimpulse AT %IX7.2: BOOL; download AT %MX2.2: BOOL;

Note: If boolean variables are assigned to a Byte, Word or DWORD address, they occupy one byte with TRUE or FALSE, not just the first bit after the offset!

'Insert' 'Declaration keywords'

You can use this command to open a list of all the keywords that can be used in the declaration part of a POU. After a keyword has been chosen and the choice has been confirmed, the word will be inserted at the present cursor position.

You also receive the list, when you open the Input Assistant (<F2>) and choose the Declarations category.

'Insert' 'Type'

With this command you will receive a selection of the possible types for a declaration of variables. You also receive the list when you access the Input Assistant (<F2>).

The types are divided into these categories:

•Standard types BOOL, BYTE, etc.

•Defined types Structures, enumeration types, etc.

•Standard function blocks for instance declarations

•Defined function blocks for instance declarations CoDeSys supports all standard types of IEC1131-3:

Syntax Coloring

In all editors you receive visual support in the implementation and declaration of variables. Errors are avoided, or discovered more quickly, because the text is displayed in color.

A comment left unclosed, thus annotating instructions, will be noticed immediately; keywords will not be accidentally misspelled, etc.

The following color highlighting will be used:

Shortcut Mode

The declaration editor for CoDeSys allows you to use the shortcut mode. This mode is activated when you end a line with <Ctrl><Enter>

The following shortcuts are supported:

5 - Editors in CoDeSys

•All identifiers up to the last identifier of a line will become declaration variable identifiers

•The type of declaration is determined by the last identifier of the line. In this context, the following will apply:

•If no type has been established through these rules, then the type is BOOL and the last identifier will not be used as a type (Example 1.).

•Every constant, depending on the type of declaration, will turn into an initialization or a string (Examples 2. and 3.).

•An address (as in %MD12) is extended around the ATATDeclaration>Proc... attribute(Example 4.).

•A text after a semicolon (;) becomes a comment (Example 4.).

•All other characters in the line are ignored (e.g., the exclamation point in Example 5.).

X %MD12 R 5 Real Number X AT %MD12: REAL := 5.0;(* Real Number *)

Autodeclaration

If the Autodeclaration option has been chosen in the Editor category of the Options dialog box , then a dialog box will appear in all editors after the input of a variable that has not yet been declared. With the help of this dialog box, the variable can now be declared.

Dialog Box for Declaration of Variables

With the help of the Class combo box , select whether you are dealing with a local variable (VAR), input variable (VAR_INPUT), output variable (VAR_OUTPUT), input/output variable (VAR_INOUT), or a global variable (VAR_GLOBAL).

With the CONSTANT, RETAIN, PERSISTENT options, you can define whether you are dealing with a constant or a retain variable

The variable name you entered in the editor has been entered in the Name field, BOOL has been

placed in the Type field. The button opens the Input Assistant dialog which allows you to select from all possible data types.

Declaration Editor...

Declaration of Arrays:

If ARRAY is chosen as the variable type, the dialog for entering array boundaries appears.

Dialog for determining array boundaries during automatic declaration

.

For each of the three possible dimensions (Dim.), array boundaries can be entered under Start and End by clicking with the mouse on the corresponding field to open an editing space. The array

data type is entered in the Type field. In doing this, the button can be used to call up an input assistant dialog.

Upon leaving the array boundaries dialog via the OK button, variable declarations in IEC format are set up based on the entries in the Type field in the dialog. Example: ARRAY [1..5, 1..3] OF INT

In the field Initial value, you may enter the initial value of the variable being declared. If this is an

array or a valid structure, you can open a special initialization dialog via the button or open the input assistant dialog for other variable types.

In the initialization dialog for an array you are presented a list of array elements; a mouse click on the space following „:="opens an editing field for entering the initial value of an element.

In the initialization dialog for a structure, individual components are displayed in a tree structure. The type and default initial value appear in brackets after the variable name; each is followed by „:=". A mouse click on the field following „:=" opens an editing field in which you can enter the desired initial value. If the component is an array, then the display of individual fields in the array can be expanded by a mouse click on the plus sign before the array name and the fields can be edited with initial values.

After leaving the initialization dialog with OK, the initialization of the array or the structure appears in the field Initial value of the declaration dialog in IEC format.

Example: x:=5,field:=2,3,struct2:=(a:=2,b:=3)

In the Address field, you can bind the variable being declared to an IEC address (AT declaration).

If applicable, enter a Comment. The comment can be formatted with line breaks by using the key combination <Ctrl> + <Enter>.

By pressing OK, the declaration dialog is closed and the variable is entered in the corresponding declaration editor in accordance to the IEC syntax.

Note: The dialog box for variable declaration you also get by the command 'Edit' 'Declare Variable'. If the cursor is resting on a variable in Online mode, the Autodeclare window can be opened with <Shift><F2> with the current variable-related settings displayed.

Line Numbers in the Declaration Editor

In offline mode, a simple click on a special line number will mark the entire text line.

In the online mode, a single click on a specific line number will open up or close the variable in this line, in case a structural variable is involved.

5 - Editors in CoDeSys

Declarations as tables

If the Declarations as table option is activated in the Options dialog box in the category, the declaration editor looks like a table. As in a card-index box, you can select the register cards of the respective variable types and edit the variables.

For each variable you are given the following entry fields.

Comment: Enter a comment here.

Both of the display types of the declaration editor can be changed without causing any problems. In the online mode, there are no differences for the display.

In order to edit a new variable, select the 'Insert' 'New Declaration' command.

Declaration Editor as a Table

'Insert' 'New Declaration'

With this command you bring a new variable into the declaration table of the declaration editor. If the present cursor position is located in an field of the table, then the new variable will be pasted in the preceding line; otherwise, the new variable is pasted at the end of the table. Moreover, you can paste a new declaration at the end of the table by using the right arrow key or the tab key in the last field of the table.

You will receive a variable that has "Name" located in the Name field, and "Bool" located in the Type field, as its default setting. You should change these values to the desired values. Name and type are all that is necessary for a complete declaration of variables.

5.2.2Declaration Editors in Online Mode

In online mode, the declaration editor changes into a monitor window. In each line there is a variable followed by the equal sign (=) and the value of the variable. If the variable at this point is undefined, three question marks (???) will appear. For function blocks, values are displayed only for open instances (command: 'Project' 'Open instance').

In front of every multi-element variable there is a plus sign. By pressing <Enter> or after doubleclicking on such a variable, the variable is opened up. In the example, the traffic signal structure would be opened up.