As you put the finishing touches on your application, you might want to provide online help to the user. LabVIEW offers several mechanisms for doing this. By using the Description and Tip option available on every front panel control and indicator, you create not only well-documented VIs, but also VIs that have extensive online help available to the user.
If you select Help»Show Context Help, the Context Help window appears.
As you move the cursor over an object, the Context Help window updates to show its description. You can programmatically show or hide the Context Help window with the Get Help Window Status and Control Help Window functions, which you find in the Functions»Application Control»Help palette.
Use this function to determine if the Context Help window is visible and the location of the upper left corner of the window.
With this function, you can control whether the Context Help window is visible, and where it will appear when shown.
You can also use the Control Online Help function to access the LabVIEW Help or custom help files that you compile using third-party tools. The type of online reference development tools you can use to develop this type of help file depend on the platform on which your application will run.
• Windows Microsoft Help (.hlp files)
• Macintosh QuickView
Get Help Window Status
Control Help Window
With this function, you manipulate an online help file. You can list the contents of the help file, jump to keywords in the file, or close the online help file.
Providing online help and reference materials for your application makes it easier to use and gives it a more polished, professional look.
VI Comparison
The LabVIEW Professional Development System includes a utility to determine the differences between two VIs loaded into the memory. From the LabVIEW pull-down menu, select Tools»Compare»Compare VIs to display the Compare VIs dialog box.
From this dialog box, you can select the VIs you want to compare, as well as the characteristics of the VIs to check. When you compare the VIs, both VIs will be displayed, along with a Differences window that lists all differences between the two VIs. In this window, you can select various differences and details to view, which can be circled for clarity.
Control Online Help
Exercise 5-4
Objective: To examine some of the built-in LabVIEW features for handling applications.
In this exercise, you will explore some of the features built into LabVIEW for handling applications.
1. Open the Application Exercise(5-3) VI you created in the previous exercise. Close any other VIs loaded into memory.
2. Select Tools»VI Revision History. The history window for the VI should appear.
3. Click Reset in the Revision History window to clear the current history.
Click Yes to confirm the deletion of the history and resetting of the revision number.
4. In the Comment box of the History window, type inInitial Application Created.and then click the Add button. Your comment should appear in the Revision History listing, along with a date and time stamp. Close the Revision History window.
5. Select Browse»Show VI Hierarchy. The application’s hierarchy appears.
6. Experiment with expanding and collapsing the hierarchy. Notice that as you click the small black and red arrows in the hierarchy, they expand or collapse branches of the hierarchy. You might see some icons with a red arrow by them, indicating that they call one or more subVIs. In addition, you might also see icons with a blue arrow next to them, which occurs when a subVI is called from multiple places in an application, but not all calls are currently indicated in the hierarchy.
7. Examine the operation of the buttons in the hierarchy toolbar. Notice how you can arrange the hierarchy using the Layout buttons or by dragging the icons, or include various application components using the Include buttons. Use Redo Layout to redraw the window layout to minimize line crossing and maximize symmetry.
8. Double-click any subVI icon in the hierarchy to display the appropriate subVI. Close the subVI you selected, and close the hierarchy window.
9. Open the Application Exercise(5-2) VI you completed in Exercise 5-2, change to the front panel of the Application Exercise(5-3) VI, and then select Tools»Compare»Compare VIs to display the Compare VIs dialog box.
10. Using the Select option, make sure that the two Application Exercises are listed in the VIs to Compare box, and that the Compare options are set as in the previous example.
11. Click Compare to display the Differences window and tile the two VIs.
Place a checkmark in the Circle Differences checkbox in the Differences window. Then, select a difference from the Differences listbox, select a detail from the Details listbox, and then click Show
12. CloseApplication Exercise(5-2).vi.
End of Exercise 5-4
C. LabVIEW Tools for Project Management
There are several tools you can add to the LabVIEW environment to assist in project development. The following section describes two of these tools that are included in the LabVIEW Professional Development System.