Add-On Instruction Definition Editor - Parameters
The table describes the settings on the
Add-On Instruction Definition Editor dialog box - Parameters
tab. Use these settings to define parameters in the Add-On Instruction.Setting | Description |
Name | The name of the parameter. Names must follow the IEC-61131 Name Standard. The IEC-61131 Name Standard, section 2.1.2 states: An identifier is a string of letters, digits, and underline characters that begin with a letter or underline character. Underlines are significant in identifiers (for example, A_BCD is interpreted differently than AB_CD). Multiple leading or multiple (consecutive) embedded underlines are not allowed, trailing underlines are not allowed, and letter case is not considered significant. Tip: In Logix Designer , most component names are limited in length to 40 characters or less.The parameter must not have the same name as another parameter or local tag in the same Add-On Instruction definition. Name is not available for members of InOut parameters. |
Usage | The usage type for the parameter: Input , Output , or InOut .
Use Auto Layout to order the layout of the parameters so that Input parameters appear first, followed by Output parameters, and then by the InOut parameters. Right-click the Usage heading to select Auto Layout .Usage is not available for members of the InOut parameters. |
Data Type | The parameter data type. Input and Output parameters are atomic data types only. During an Add-On Instruction call, Input and Output parameters are passed by value. InOut parameters are atomic or complex data types (that is, structures or arrays). InOut parameters are always passed by reference. Data Type is not available for members of the InOut parameters and the alias parameters. |
Alias For | The local tag or its member to be an alias of the parameter. For the Add-On Instruction definition, only Input and Output tags can alias local tags. Local tags and InOut tags cannot alias another tag. Use only one input and one output alias per local tag. Alias For is not available for members of the InOut parameters. |
Default | The default value that is set when an Add-On Instruction of this type is instantiated. This defines the default values that initially come from the data type. Default is not applicable to InOut parameters or their members because InOuts are passed by reference. |
Style | If it is set to Visible, the style displayed on the faceplate for this parameter. Or, the style displayed in the Tag Editor or Data Monitor .The Style box is read-only for members of the InOut parameters.These settings are available:
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Req | Determines whether the parameter requires an argument. Req is selected and read-only by default for the InOut parameters because by-reference parameters require an argument. Right-click the Req heading to select or deselect all the rows in the Req column. |
Vis | Determines whether the parameter is visible on the Ladder Diagram and Function Block Diagram instructions when the Add-On Instruction is called. Right-click the Vis heading to select or deselect all the rows in the column.If Req is selected, Vis is selected and read-only. The Visible function is not applicable for members of InOut parameters.If the parameter is not required, the Visible configuration may be overridden for Add-On Instruction called in Function Block Diagrams routines. Overriding the visibility at the instruction call level does not affect the definition configuration. |
Description | A description for the parameter. If a Parameter does not have a description, the description of the data type is passed through. Because only complex data types have descriptions, only InOut parameters potentially have a description passed through to the parameter. A member of an expanded parameter shows its description, if it has one, on that member in the definition itself. If a member is of another Add-On Instruction type and has its own description defined, which is shown in black text, and passes its description to a member without a description, the description concatenation occurs during pass-through. The description is concatenated with the description from the base tag, which is shown in gray text. |
External Access | Determines whether the tag has Read/Write , Read Only , or no access (None ) from external applications such as HMIs. |
Constant | Select the Constant check box to prevent executing logic from writing values to the associated tag or parameter. If a logic routine tries to write to a constant tag, the routine will not verify. The Constant check box is not available for all tag types.Tip: You can use the Data Monitor dialog box to write values to the parameter. The Value boxes in all other browsers and language editors are disabled when the tag is a Constant tag. Changes made to the values of constant tags are recorded in the Controller Log for future reference. |
Can Be Null | Use to allow the Add-On Instruction invocation to pass in a value of 0 as an argument instead of an actual tag. When Can Be Null is selected, Add-On Instruction invocation allows for 0 or an actual tag to be assigned as an argument.When Can Be Null is not selected, Add-On Instruction invocation only allows for an actual tag to be assigned as an argument. Can be Null is enabled only for InOut parameters. |
Hide and Show Columns | To hide columns in the dialog box, right-click a column header and select Hide Column . To display a hidden column, right-click any column header and select Toggle Column > [column] . |
Editing Modes | An asterisk appears in the first column in the dialog box to indicate that changes have been made to a parameter that have not yet been applied. |
Popup Menu | Right-click a parameter to display options of operations to perform. |
Move Up | Moves the selected row or rows of parameters up. Parameters are displayed on the instruction and in the Data Type in the order set on the Parameters tab Also change the parameter order using drag and drop.The EnableIn and EnableOut parameters are at the top of the list and you cannot change their order. |
Move Down | Moves the selected row or rows of parameters down. Also, change the parameter order using drag and drop. |
Copy all default values of parameters and local tags whose values were modified to all tags of this instruction type | Copies all the default values of the parameters, local tags, or members' default values that have changed to all tag instances of this instruction type. |
Logic | Opens the Logic routine. Logic is not visible if the Add-On Instruction is locked using source protection. |
Data Type Size | Displays the size of the Add-On Instruction data type. The value includes the size of any local tags, even though local tags are not visible when an instance tag of this data type is expanded in the Tag Editor or Data Monitor . However, this value does not include logic size. The size is automatically updated when you Apply the instruction, not as you create the parameters and local tags. |
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