Your objective is to open, run, and explore the components of a VI.
Open the Temperature System Demo VI.
In the LabVIEW dialog box, click the Find Examples button to display the Find Examples dialog box. If you already opened a VI, select Help»Find Examples to display the Find Examples dialog box.
Click the Search tab and enter temperatures.
From the list of examples, double-click Temperature System Demo.vi to open the VI.
You also can open the VI by selecting File»Open and navigating to labview\examples\apps\tempsys.llb\Temperature System Demo.vi.
Front Panel
This VI simulates a temperature acquisition and analysis application. The VI compares the temperature value to a high and low value and displays the value on the chart, and plots a histogram of the data on another chart.
Run the VI by clicking the Run button in the toolbar. The button changes appearance to indicate that the VI is running.
Select Window»Show Tools Palette to display the Tools palette.
If the Automatic Tool Selection LED in the Tools palette is not lit, click the Automatic Tool Selection button to enable automatic tool selection.
Move the cursor over the slider in the System Controls section. LabVIEW selects the Operating tool.
Click and drag the slider to change the value. Notice the speed of the simulated acquisition changes as you change the value.
You operate LabVIEW controls just as you would similar real controls. Other ways to operate knob controls using the Operating tool include:
Clicking the black region of the slider to move the slider to the value at the point you clicked.
Clicking the digital display and entering a number. If you use this method, the Enter button appears on the toolbar. LabVIEW does not pass the value to the control until you click this button or press the <Enter> key. Macintosh Press the <Return> key to enter the value.
Click the Abort Execution button in the toolbar to stop the VI.
Block Diagram
Display the block diagram for the Temperature System Demo VI by selecting Window»Show Diagram. This block diagram contains several basic elements of LabVIEW programming, including structures, functions, and subVIs. You also can press the <Ctrl-E> keys to display the block diagram. Macintosh Press the <Command-E> keys.
Double-click the Temperature Status subVI icon to display the front panel of the subVI.
Click the Run Continuously button and adjust the value of the High Limit and Low Limit knobs. Notice the Temperature Status VI is a fully functional VI that performs basic comparisons between the Temperature and the High Limit and Low Limit values. When the temperature is greater than the High Limit, the Over Limit indicator turns red. When the temperature is less than the Low Limit, the Under Limit indicator turns blue.
When you run the Temperature System Demo VI, it calls the Temperature Status subVI to perform this basic comparison.
Click the Run Continuously button again to stop the VI from continuously running.
Close the front panel for the Temperature Status VI by selecting File»Close.
Do not close the Temperature System Demo VI, because you will use it in the next activity.