Course Manual

In the block diagram right-click and navigate to the HandsOnPi2040 Driver Palette.

LabVIEW will not let you run the source-code until these errors are sorted. Close the Error List and select all of the Vis. (Left-click drag on mouse).

Press Ctrl+space to bring up quick drop and Ctrl+W to wire the VIs together. Quick drop is an extremely useful productivity tool that ships with LabVIEW. It allows you to automate repetitive tasks with a few key combos.

Press Ctrl-H to bring up the context help window. Hover over Initialize.vi.

Now, right-click on VISA Resource Name Initialize.vi and select create constant.

Right click on the ‘True’ Boolean Constant. This will bring up a drop down window, hover over ‘Visible Items’ and select ‘Label’.

Finally let’s wire in a couple of outputs.

Right-click on IDN for Initialize.vi and select ‘Create Indicator’. Then we need an error out, so right click at the bottom the Close.vi and select ‘Create Indicator’.

The VIs don’t know who they are talking to. To fix this, hardware users need to set the correct VISA reference from the ‘VISA’ drop down box.. For Emulator users click the ‘Copy’ button, as seen in the image below and paste the reference in, if you have hardware refresh and select the ASRL reference.

Now press run again.

Make your workspace bigger to allow space for adding objects. Use Ctrl then drag to expand.

Now insert a For Loop, to do this right click anywhere on the block diagram to bring up the functions palette. Select ‘Structures’ then ‘For Loop’.

You will only need to place the For Loop around the WriteDO SubVI (and the constants attached to it.)

Once the For Loop has been placed, you will see an ‘N’ in the top left corner, this is the loop count (or how many times the loop will execute.)

Right click on the left hand side of the Loop Count, and select ‘Create a Constant’. For this task you will need the Loop Count to be 20 (10 times on and 10 times off.)

Right click on the edge of the For Loop and select ‘Add Shift Register.’ Wire the True Constant to the Shift Registers and the DO (Value) wire terminal.

For a blinking LED you will need to invert the boolean value after every loop. To do this right click anywhere to bring up the functions palette. Hover over ‘Boolean’ then select the ‘Not’ Boolean. Wire this into the shift registers.

Right click inside the For Loop, hover over ‘Timing.’ There will see many different timing options. For this you will use the ‘Wait’ function. Select and place inside the Loop.

Create a constant by right clicking on the left side of the ‘Wait’ function. The ‘Wait’ function executes in milliseconds, therefore to slow down the Loop by 5 seconds, write 500.

Now Run the program. You have successfully used a For Loop to blink the Digital Output.

Firstly, right click on the edge of the For Loop, and select ‘Replace with While Loop’

Now the For Loop has been replaced, the Loop Count is not connected. This is not needed for a While Loop and can be deleted.

To add a ‘Stop’ boolean, switch to the front panel window and right click where you want to place the button. The Controls palette will appear, select ‘Boolean’ and pick a button. The example uses a ‘Push Button’ but any will work.

Back on the Block Diagram move the new Control Boolean into the While Loop and wire it up to the Conditional Terminal in the bottom right corner. If the Button on the Front Panel is pressed when the program is running then the Loop will end and the ‘blinking’ LED will stop.

First lets delete the while loop and its contents. Click on the While Loop and press the delete key. Do the same for the ‘True’ constant. Then remove the broken wires with Ctrl+B.

Right click to bring up the Functions Palette, hover over ‘Structures’ then select ‘Event Structure.’ Place the Event Structure on the Block Diagram.

Wire the Initialize VI and the Close VI through the Event Structure.

Add a new Event Case by right clicking on the Selector Label, and select ‘Add Event Case.’

Add the WriteDO.vi by bringing up the Functions Palette, hover over ‘Instrument I/O’, ‘Instr Drivers,’ ‘HandsOnPi2040,’ and select ‘WriteDO.vi.

Drag the sub VI inside the Event Structure and wire it up. Right click the Output terminal and create a Constant.

Change the Output from ‘No DO – Error’ to ‘DO1’ by clicking the drop down arrow on the Output Constant.

Next we need to add a button for the Digital Output. Go to the Front Panel, and right click anywhere to bring up the Controls Palette. Hover over ‘Boolean,’ and select ‘Push Button’

Wire the new Boolean Control into the ‘DO Value’ terminal.

Right click on the Label Selector as we need to ‘Edit Events Handled by This Case.’

This will bring up the ‘Edit Events’ window. Select ‘Boolean.’

This Event Case is now complete. We will need 3 more Event Cases, each one corresponding to a LED. The easiest way to do this is to right click the Label Selector, and select ‘Duplicate Event Case.’

Select ‘Boolean 2’ on the Edit Events window.

It’s important to change the DO Constant when the case has been duplicated. (DO1 for Boolean, DO2 for Boolean 2, etc.) Duplicate this case 2 more times for DO3, and DO4.

At this point your Front Panel may look a little messy, take some time to clean it up. This will make it easier to use when you have finished building the program.

Back on the Block Diagram we will need to add a While Loop. Right click to bring up the Functions Palette, hover over ‘Structures’ and select ‘While Loop.’

Place the While Loop around the Event Structure.

Go to the Front Panel, so we can add a ‘Stop’ button that we’ll connect to the Loop Condition. Right click to bring up the Controls Palette, hover over ‘Boolean, then select ‘Stop Button.’

We will also need to create a new Event Case for this Stop button. Right click on the Selector Label and select ‘Add Event Case.’

Place the ‘Stop’ control inside the new case.

Right click the Selector Label and select ‘Edit Events Handled by This Case’

When the ‘Edit Events’ window pops up choose the ‘stop’ option in the ‘Event Sources’ table.

Our last step is to wire a ‘True’ constant to the Loop condition. Right click to bring up the Functions Palette, hover over ‘Boolean’ and select ‘True Constant.’

Place the Constant inside the Event Structure.

Wire the constant to the Loop Condition, like the image below.

The program will now run successfully. You will be able to turn the LEDs on and off as many times as you want. You can use the Stop button to stop the execution of the program.

Beginning with a Block Diagram with an Initialize.vi and a Close.vi. Right click to bring up the Functions Palette. Follow along with the image below and add the WriteAO.vi onto the diagram.

Wire up the 3 VIs.

Right click on the ‘Analog Output’ terminal and Create a Constant. For this exercise the Analog Output will produce 2 different pieces of numerical data, therefore 2 constants will be grouped into a Cluster.

You will need to create a Bundle. Right click on the Block Diagram to bring up the Functions palette, hover over ‘Cluster, Class, & Variant, then select ‘Bundle By Name.’

Delete the wire connected to the subVI, as it needs to be wired into the bundle you built before.

Wire the bundle and the like the image below.

Once wired up, you will notice that the bundle has the label ‘Duty’. Expand the Bundle down so the ‘Frequency’ label is visible.

Right click at the edge of the bundle and create Constants for ‘Duty’ and ‘Frequency.’

The front panel should look like the image below. However, this needs some adjusting.

Right click on the ‘Duty’ Control and hover over ‘Replace.’ Select ‘Numeric’ and then ‘Vertical Pointer Slide.’ Do the same for the ‘Frequency’ Control.

You will need to change the ‘Scale’ of the ‘Frequency’ slider. Right click on the Slider, select ‘Scale’, ‘Mapping’, then ‘Logarithmic.’

The ‘Duty’ slider can stay as a Linear scale.

Now you need to set the top and bottom points on the sliders. You will only need to change the highest point for ‘Duty’. Set it to ‘1’.

For ‘Frequency’ the lowest point should be ‘10’ and the highest ‘500,000.’

Bring up the Functions Palette by right clicking on the Block Diagram, hover over ‘Structures’ and select a For Loop. Place the For Loop around the WriteAO.vi.

A For Loop needs a ‘Loop Count.’ Choose a number that will allow you to time to use the dials and see how it executes on the Waveform Chart.

You will need to slow down the Program before running it. Bring up the Functions Palette, select ‘Timing’ and place the ‘Wait (ms)’ function inside the For Loop.

Right click the left hand terminal on the Wait function and create a Constant. Type in ‘100’ this will slow the program down enough for you to see the results.

You can now run your program. Move the Vertical Pointer Slides up and down and you will be results will show on the Emulator.

Front Panel

Block Diagram

Icons, Connector Panes, and SubVIs

Integer (int) – whole numbers (e.g., -700, 0, 700)

Floating point (float) – numbers with fractions (decimals) (e.g., 700.0, 0.7)