Describing VIs, Controls, and Indicators

Aide LabVIEW 2014

Date d'édition : June 2014

Numéro de référence : 371361L-0114

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Integrate information for the user in each VI you create by using the VI description feature, by adding instructions to the front panel, and by including descriptions for each control and indicator.

Creating VI Descriptions

Create and edit VI descriptions by selecting File»VI Properties and selecting Documentation from the Category pull-down menu. The VI description is often the only source of information about a VI available to the user. The VI description appears in the Context Help window when you move the cursor over the VI icon and in any VI documentation you generate.

Include the following items in a VI description:

  • An overview of the VI
  • Instructions for using the VI
  • Descriptions of the inputs and outputs

You also can link from the VI to an HTML file or compiled help file.

Documenting Front Panels

One way of providing important instructions is to add a block of text to the front panel. A list of important steps is valuable. Include instructions such as, “Select File»VI Properties for instructions” or “Select Help»Show Context Help.” For long instructions, use a scrolling string control instead of a free label. When you finish entering the text, right-click the control and select Data Operations»Make Current Value Default from the shortcut menu to save the text.

If a text block takes up too much space on the front panel, add a Help button to the front panel instead. Include the instruction string in the help window that appears when the user clicks the Help button. Use the Window Appearance page in the VI Properties dialog box to configure this help window as either a dialog box that requires the user to click an OK button to close it and continue, or as a window the user can move anywhere and close anytime.

You also can use a Help button to open an entry in a help file. Use the Help functions to open the Context Help window or to open a help file and link to a specific topic.

Creating Control and Indicator Descriptions

Include a description for every control and indicator. To create, edit, and view object descriptions, right-click the object and select Description and Tip from the shortcut menu. The object description appears in the Context Help window when you move the cursor over the object and in any VI documentation you generate.

Unless every object has a description, the user looking at a new VI has no choice but to guess the function of each control and indicator. Remember to enter a description when you create the object.

Note  If you copy the object to another VI, you also copy the description. You might need to change the description for the new object.

Every control and indicator needs a description that includes the following information:

  • Functionality
  • Data type
  • Valid range (for inputs)
  • Default value (for inputs)—You also can list the default value in parentheses as part of the control or indicator name.
  • Behavior for special values (0, empty array, empty string, and so on)
  • Additional information, such as if the user must set this value always, often, or rarely

Designate which inputs and outputs are required, recommended, and optional to prevent users from forgetting to wire subVI connections. To indicate the required, recommended, and optional inputs and outputs, right-click the connector pane, select This Connection Is from the shortcut menu, and select Required, Recommended, or Optional.

Note  For dynamic dispatch member VIs, you can select Dynamic Dispatch Input (Required) or Dynamic Dispatch Output (Recommended).


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