Command: Edit Parameters

Function: The Edit Parameters dialog is used to manage the constant input parameters of a function block.

Call: CFC → Edit Parameters menu; context menu or click the Parameters function block field

Requirements:

A CFC editor is active.
A function block is instantiated and has VAR_INPUT CONSTANT variables in its declaration.

Function blocks with VAR_INPUT CONSTANT variables are displayed in the editor with the Parameter word in the lower left corner of the box.

Note

This functionality applies only to boxes which have been inserted into a CFC with CODESYS >= V3.5 SP4.

Note

Only the CFC editor has this functionality for its VAR_INPUT CONSTANT variables.

In the FBD editor, CODESYS always displays all input parameters on the box, regardless of whether or not they are declared as VAR_INPUT or VAR_INPUT CONSTANT. CODESYS also does not make a distinction about this in text editors.

Dialog: Edit Parameters

Parameters	Name of the constant input variable Example: `iConst` If the input variable is marked with the `{attribute 'parameterCategory':= '<category name>'}` pragma, then the variable will be categorized and listed below the specified category.
Type	Data type of the variable For a custom data type, this is the DUT name. Example: `EXAMPLE`
Value	Transfer values to the function block instance Manually specified value Note The value has to be compatible with the data type. For input variables with custom `STRUCT` data type, the transfer value follows the syntax: `STRUCT( <name of first component> := <value>, <name of next components> := <value> )`. The structure name is listed under Type. Example: `STRUCT(x1:= TRUE, i1:=222, str1 := 'second')` Read out automatically in online mode as "prepared value". Prepared values are displayed in brackets. Read out from the controller in online mode. This value is highlighted in red with a red frame Tip Click into the field to specify the desired value.
Initial value	Initial value from the declaration
Min	Minimum value from the declaration if the variable was marked with the `{attribute 'parameterMinValue':= '<value>'}` pragma
Max	Maximum value from the declaration if the variable was marked with the `{attribute 'parameterMaxValue':= '<value>'}` pragma
Unit	Unit from the declaration if the variable was marked with the `{attribute 'parameterUnit':= '<value>'}` pragma
Description	Comment from the declaration
Clear Prepared Parameters	Deletes prepared values which are displayed in brackets You can load and run the application in online mode and in that time parameterize the function block instance with values. To do this, specify prepared values for the input variable and click Debug → Write Values. These values are then prepared here as possible transfer values. Tip Delete the prepared values if you do not want to use them. Note The command is active when you write a prepared value to a variable in online mode (Debug → Write Values command).
Save Prepared Parameters to Project	Saves the transfer values and parameters in the project so that they can be used during the next online mode. Note The command is enabled when you have written or forced values in online mode and are back in offline mode.
Close	Accepts the configured values and closes the dialog

Example 5. FB_Test function block

TYPE EXAMPLE :
STRUCT
    x1 : BOOL;
    i1 : INT;
    str1 : STRING;
END_STRUCT
END_TYPE

TYPE COLOR :
(
	yellow,
	green,
	blue,
	black
) // Basic data type is INT, default initialization for all COLOR_BASIC variables is yellow
;
END_TYPE


FUNCTION_BLOCK FB_Test

VAR_INPUT CONSTANT
	xConst  : BOOL := FALSE; // Boolean value
	{attribute 'parameterCategory':='General'}
	{attribute 'parameterUnit':= 'm/s'}
	{attribute 'parameterMinValue':= '0'}
	{attribute 'parameterMaxValue':= '100'}
	iConst	: INT := 0; // Integer
	strConst : STRING := 'Hello World'; // String
	exampleConst : EXAMPLE := (x1 := TRUE, i1 := 1, str1 := 'first'); // STRUCT
	colorConst : COLOR := yellow; // ENUM
END_VAR

VAR_OUTPUT
END_VAR

VAR
END_VAR

;

PROGRAM PLC_PRG
VAR

	xStart : BOOL;
	fbTest	: FB_Test;

END_VAR

Figure 1. Implementation

Figure 2. Dialog with parameters of fbTest