LabVIEW PDA Module Getting Started Guide for LabVIEW Base Development System

Use this tutorial to learn how to create a LabVIEW project and build, run, and debug a PDA application. The VI in this tutorial creates a variable frequency sine wave using LabVIEW PDA functions.

Creating the LabVIEW Project

Use LabVIEW projects to group together LabVIEW files and non-LabVIEW files, create build specifications for building a PDA VI into a PDA application, and deploy the PDA application to a PDA device or emulator. You must use a project to build a PDA VI into a PDA application.

Complete the following steps to create a LabVIEW project, add a PDA target, and add a new PDA VI to the project.

1. Launch LabVIEW. In the Getting Started window, select Empty Project to open an empty LabVIEW project in the Project Explorer window as shown in Figure 1. LabVIEW creates an empty project with a Windows target, shown in Figure 1 as My Computer.

   

   Figure 1. Project Explorer Window

2. Right-click the project, which is Project:Untitled Project 1 in Figure 1, in the Project Explorer window and select New » Targets and Devices from the shortcut menu to open the Add Targets and Devices dialog box as shown in Figure 2.

   

   Figure 2. Add Targets and Devices Dialog Box

3. Expand the PDA folder and select Windows Mobile 5.0 Pocket PC
   Emulator as shown in Figure 3.

   

   Figure 3. Adding a New Device

4. Click OK to add the target to the project. The target appears in the Project Explorer Window as shown in Figure 4.

   

   Figure 4. Adding the Windows Mobile 5.0 Pocket PC Emulator to the Project Explorer Window

5. Expand the PDA target. In Figure 5, the PDA target is Windows Mobile 5.0 Pocket PC Emulator. LabVIEW automatically adds Dependencies and Build Specifications under the target. SubVIs appear under Dependencies when you add a VI that contains subVIs to a project. Build specifications you create for a target in a project appear under Build Specifications in the Project Explorer window.

   

   Figure 5. Expanding the PDA target in the Project Explorer

6. Right-click on Windows Mobile 5.0 Pocket PC Emulator and select New PDA VI. This will bring up a template selection allowing you to pick between portrait and landscape screen layouts shown in Figure 6. These templates are custom sized for PDA screens. Select PocketPC Portait Screen and click OK.

   

   Figure 6. Selecting a layout for the PDA Template

7. This will open a PDA template with code already on the Block Diagram. Open the Block Diagram by selecting Window » Show Block Diagram. Notice that the there is a while loop and case structure already. This will allow the code that is placed in the True case of the case structure to run when the Run button is pressed on the Front Panel. The program will stop the while loop and exit when the Stop button is pressed.

   

   Figure 7. Template Block Diagram Code

8. Save the VI as PDA Tutorial.vi.

Creating the PDA VI

LabVIEW PDA using the some of the functionality of LabVIEW. When a VI is targeted to a PDA, only the VIs that are available to that target are available on the palettes.

Complete the following steps to construct a VI that will simulate a sine wave with a variable offset and frequency and display that sine wave on a graph.

Front Panel

1. Open the PDA Tutorial.vi that was saved previously. This should open to the Front Panel, but if not select Window » Show Front Panel.
2. Add a graph to the Front Panel. The graph can be found on the Controls » Modern » Graph » PDAWaveformGraph_2x. Notice that all PDA controls have been resized to allow them to be displayed property on a PDA screen.

   

   Figure 8. PDA Graph Palette

3. Place two sliders on the Front Panel, one horizontal and one vertical. Sliders can be found Controls » Modern » Numeric » HControl_2x and VControl_2x.

   

   Figure 9. PDA Numeric Palette

4. To complete the Front Panel controls should be named and control settings need to be adjusted. Right-click on the Vertical Slide and select Properties. This will bring up the Property page for that control. Change the following properties to name the control Offset and allow you to adjust the offset of the sine wave from -2 to 2. Make sure to press OK when done configuring the properties.

   Appearance » Label = Offset

   Scale » Scale Range » Minimum = -2

   Scale » Scale Range » Maximum = 2

5. Right-click the Horizontal Slide control and select Properties. Change the following properties to name the control Frequency and allow you to adjust the frequency of the sine wave by a factor of 0 to 6:

   Appearance » Label = Frequency

   Scale » Scale Range » Minimum = 0

   Scale » Scale Range » Maximum = 6

6. Right-click the Wavefrom Graph indicator and select Properties. To make the graph display the data properly, me must turn off Autoscaling (which automatically scales the axes) and set the y-axis min and max to -4 and 4. This can be done by selecting Scales from the tabs at the top and then clicking the drop-down menu and selecting the y-axis. Make the Property Page look like the following by unchecking the Autoscaling option and setting the min and max to -4 and 4.

   

   Figure 10. Waveform Graph Property Page

7. Rearrange the Front Panel to look similar to the Figure 11.

   

   Figure 11. Complete PDA Tutorial Front Panel

8. Save the VI.

Block Diagram

1. Show the Block Diagram by selecting Windows » Show Block Diagram.
2. Place a Wait function inside the While loop. When programming for PDA always remember to place wait functions in while loops to free the processor. This will make your PDA application run much better. The Wait functions are found on the Functions » Programming » Time, Dialog & Error. Right-click on the function and select Create » Constant and type 150. This will configure the Wait function to wait for 150 ms.

   

   Figure 12. PDA Time, Dialog & Error Palette

3. To configure 100 points for the sine wave we will use a For Loop. This is found under the Functions » Programming » Structures palette. Place the For Loop on the Block Diagram. On the loop count terminal (N), right-click and select Create » Constant and type 100.

   

   Figure 13. PDA Structures Palette

4. The remainder of the code is to calculate the points of the sine wave. The iteration count of the For Loop is used as the independent variable. This is scaled by the Frequency control, which is then an input to the Sine function. The output of the Sine function is then added to the Offset control. Complete the remainder of the Block Diagram to look like the following.

   

   Figure 14. Completed Tutorial Block Diagram Code

5. Save the VI.

Creating the PDA Build Specification

Build specifications contain the build settings and code generation options to use when you build a PDA VI into a PDA application. You can create the build specification when you create a project or wait until you are ready to build the PDA VI into a PDA application.

You can have multiple build specifications for the same target. For example, you might want one build specification that generates debugging information and another build specification that does not generate this extra information.

Complete the following steps to create a build specification.

1. Right-click Build Specifications under the PDA target and select New » Application (EXE) from the shortcut menu.
2. LabVIEW prompts you to save the project. Click the Save button when prompted and save the project as PDA Tutorial.
3. Click the Help button to open the LabVIEW Help and read a description of each build setting.
4. Enter PDA Tutorial in the Build specification name text box as shown in Figure 15.

   
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   Figure 15. Creating the Build Specification

5. Select Source Files from the Category list and select PDA Tutorial.vi in the source files list. Click the blue right arrow button to move the VI from the source files list to the Top-level VI text box as shown in Figure 16.

   
   [+] Enlarge Image

   Figure 16. Selecting the Top-Level VI for the Application

   Note: The Machine Alias category is not used in this tutorial. You use the Machine Alias category to overwrite the default IP address of a shared variable host target so you can move the shared variable to a different host without rebuilding the application. Refer to the Using Shared Variables in PDA and Touch Panel VIs topic in the LabVIEW Help for more information about using shared variables.

6. Select the Generated Files category to view the filenames and path to the files the PDA Module will generate when you build the PDA Tutorial VI into a PDA application.
7. Click the OK button. The build specification you just created appears in the Project Explorer window under the PDA target as shown in Figure 17.

   

   Figure 17. PDA Build Specification in the Project Explorer Window

8. Select File » Save Project in the Project Explorer window to save the project. Build specifications are saved with the project.

Building the PDA VI into a PDA Application and Deploying

After you develop the PDA VI on the host computer, you build the PDA VI into an executable PDA application that you can run on a PDA target. Pick one of the options in the Using the Shortcut Menu section or the Using the Run Button section to build, run, and deploy a PDA application.

Note: ARM PDA emulators require a few minutes to load the OS before you see the PDA application running on the emulator target.

Using the Shortcut Menu

Right-click the build specification and select one of the following from the
shortcut menu:

• Deploy — Builds the PDA VI into a PDA application, if necessary, and deploys the application to the PDA target. This option does not automatically run the PDA application.
• Run — Builds the PDA VI into a PDA application, if necessary; deploys the application to the PDA target, if necessary; and automatically runs the PDA application.
• Build — Builds the PDA VI into a PDA application. This option does not deploy or automatically run the PDA application.

Using the Run Button

The behavior of the Run button differs from LabVIEW for Windows:

• If you want to build, run, and deploy—Click the Run button in a PDA VI to build the PDA VI into a PDA application, deploy the PDA application to the PDA target, and run the PDA application on the PDA target. LabVIEW prompts you to create a build specification if you do not have an existing build specification for the PDA VI. If you have multiple build specifications, the PDA Module uses the default build specification, which the PDA Module indicates with a green square
  around the PDA build specification glyph in the Project Explorer window.
• If you want to build without deploying or running—Press the <Ctrl> key while you click the Run button in a PDA VI to build the PDA VI into a PDA application without deploying or running the PDA application. LabVIEW prompts you to create a build specification if you do not have an existing build specification for the PDA VI. If you have multiple build specifications, the PDA Module uses the default build specification, which the PDA Module indicates with a green square around the PDA build specification glyph in the Project Explorer window.

Closing the PDA Application

Click the Exit button in the PDA application on the PDA target to close the PDA application.

Debugging the PDA Application

You must create a build specification that enables debugging before you can debug a PDA application. Enabling debugging generates extra debugging information and can significantly increase the size of the PDA application.

When LabVIEW on the host computer connects to the PDA target, the PDA application runs on the PDA target. The front panel is fully functional on the PDA target. However, the front panel controls have no effect on the PDA application, and the indicators of the PDA VI on the host computer do not reflect the execution of the PDA application on the PDA target.

The block diagram acts as a conduit between the PDA application running on the PDA target and the PDA VI running on the host computer, where you can probe signals, set breakpoints, and step through code as you do in any other VI.

Tip: You can modify an existing build specification by double-clicking the build specification in the Project Explorer window or right-clicking the build specification and selecting Properties from the shortcut menu. This tutorial creates a second build specification for debugging.

Creating a Debugging Build Specification

Complete the following steps to create a debugging build specification.

1. Right-click Build Specifications under the PDA target and select New » Application (EXE) from the shortcut menu.
2. Enter (Debug) PDA Tutorial in the Build specification name text box.
3. Remove the checkmark from the Same as top-level VI checkbox so you can change the PDA application name.
4. Enter (Debug) PDA Tutorial.exe in the Target filename text box.
5. Place a checkmark in the Enable debugging checkbox to generate debugging information when you build the PDA VI into a PDA application as shown in Figure 18.

   
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   Figure 18. Creating the Debugging Build Specification

6. Select Source Files from the Category list and select PDA Tutorial.vi in the source files list. Click the blue right arrow button to move the VI from the source files list to the Top-level VI text box.
7. Click the OK button. The build specification you just created appears in the Project Explorer window as shown in Figure 19.

   

   Figure 19. Two Build Specification in the Project Explorer Window

Adding a Probe to the PDA VI

Probes display information about the data that passes through a wire. As you interact with the PDA application on the PDA device, you can see the data passing through the wire in the PDA VI on the host computer.

Complete the following steps to add a probe to the PDA VI.

1. Select Window » Show Block Diagram in the VI to open the Block
   Diagram if it is not visible.

   Note: Double-click the VI in the Project Explorer window to open the VI if the VI is not already open. The Block Diagram acts as a conduit between the PDA application running on the PDA target and the PDA VI running on the host computer.

2. Right-click the wire that is flowing from the Frequency control to the for loop and select Probe from the shortcut menu.

   A floating Probe window appears after you create a probe. LabVIEW numbers the Probe windows automatically and displays the same number in a glyph on the wire you probe as shown in Figure 20.

   

   Figure 20. Adding the Probe to the Block Diagram

Deploying and Debugging a PDA Application

You must use the debug build specification to deploy the PDA VI, which contains debugging information, to the PDA device before the probe in the PDA VI on the host computer can update the values passing through the wire.

Complete the following steps to deploy and debug the PDA application.

1. Right-click the build specification for the PDA VI you want to build and deploy, which is (Debug) PDA Tutorial in Figure 19, and select Debug from the shortcut menu. Save any VIs if prompted.

   The PDA Module builds the PDA VI into a PDA application, deploys the PDA application to the PDA target, and runs the PDA application on the PDA target as shown in Figure 21.

   

   Figure 21. Running the PDA Application on the PDA Emulator

   Tip: You also can start a debugging session by clicking the Step Over or Step Into buttons or by clicking the Pause button and then clicking the Run button on the block diagram toolbar.

2. Move the Frequency slider in the PDA application running on the PDA target and click the Run button. The value in the Probe window on the block diagram updates as you move the slider in the PDA application.

   Note: Any changes you make on the front panel of the PDA VI on the host computer have no effect on the PDA application running on the PDA target.

3. Click the Exit button in the PDA application on the PDA target to stop the PDA application and end the debugging session.

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