CHAPTER 2 : CUSTOMIZING A VI

Okay guys this will be the next things after we try out the 'GETTING STARTED TO LAB VIEW'

OPEN A BLANK VI

First we start with blank VI. So next add VIs Expression to complete the specific task.

Getting started >> blank VI in the New section.

Blank front panel window and block diagram window appear.

Function palette not visible? then, right click any blank space on the block diagram to display Function Palette.

ADDING AN EXPRESS VI THAT SIMULATES A SIGNAL 

To open context help

Help >> Show context help (from the blog diagram and front panel)

On the Function Palette >> Express >> Input Palette. Then move the cursor over one of the input palette. When you move the cursor over a VI, the Context Help window displays information about that VI.

Use the information that appears in the Context Help window to find the Express VI that can simulate a sine wave signal.

Select Express VI > Configure Stimulate Signal ( dialog box appear).

Move the cursor over the various option in the “Configure Stimulate Signal”

The dialog box will appear. Frequency and Amplitude will appear. Read the information that appears in the context help windows.

Generate a sine wave with frequency = 10.7 and amplitude =2.

The signal in the Result Preview window changes to reflect the configured sine wave.

 

Click the OK button to save the current configuration and close the Configure Simulate Signal dialog box.

Move the cursor over the stimulate signal express VI and read the information that appears in the context help window it will display the addition standard context help description. And then save the VI.

SEARCHING THE HELP AND MODIFYING SIGNAL 

On the block diagram, move the cursor over the stimulate signal express vi to display the context help >> detailed help link to display the stimulate signal topic in the Labview help.

Search tab >> sample compression >> enter >> double click 

add to the block diagram >> move the cursor to block diagram >> add sample compression express VI to the block diagram

Use View >>Quick drop ( find easily the item) >> configure the sample compression expres VI to reduce the signal by a factor 25 using the mean of these values >> ok >>close the configure sample compression dialog box.

Use the Wiring tool to wire the Sine output of the Simulate Signal Express VI to the Signals input of the Sample Compression Express VI.

CUSTOMIZING A USER INTERFACE FROM THE BLOCK DIAGRAM 

Right click the Mean o/p of sample, then Create >> Numeric Indicator >> mean indicator appear shown at left.

Right-click the wire that connects the Sine output of the Simulate Signal Express VI to the Signals input of the Sample Compression Express VI and select Create>>Graph Indicator from the shortcut menu.

Use the Wiring tool to wire the Mean output of the Sample Compression Express VI to the Sine graph indicator.

The merge signals function will appears.

Rearrange the object > display the front panel

CONFIGURING A VI TO RUN CONTINUOUSLY UNTIL THE USER UNTIL THE USER STOP IT 

Add while loop >> execution control >> move the cursor to the upper left corner of the block diagram and drag the cursor diagonally to enclose all the express VIs  >> release the while loop>> stop button will appear 

DISPLAY THE FRONT PANEL AND RUN THE VI 

The VI now runs until you click the STOP button. A While Loop executes the VIs and functions inside the loop until the user clicks the STOP button.

Click the STOP button and save the VI.

USING THE ERROR LIST WINDOW 

Display front panel >> Click mean indicator >> shown at left >> press delete key >> display block diagram .

A wire appears as a dashed black line with a red X in the middle, shown at left. The dashed black line is a broken wire. The Run button, shown at left, appears broken to indicate the VI cannot run.

Click broken run >> display error list window >> in the error and warnings list >> select the  wire has loose ends error >> click help

Select view >> error list >> click close button to close the error list window >> run button no longer appears broken.

CONTROLLING THE SPEED OF EXECUTION 

On the block diagram, search for the Time Delay Express VI, shown at left, on the Functions palette and place it inside the While Loop. You can use the Time Delay Express VI to control the execution rate of the VI.

Enter 0.25 >> time delay text box >> click ok >> close the configuration time delay dialog box

Display the front panel >> and run the VI>> click enable switch and examine the graph

(if the enable switch is on = the graph display reduced the signals. If the enable switch off = graph does not display the reduced signal )

Click stop button to stop the VI

USING A TABLE TO DISPLAY DATA 

Control >> search for Express Table indicator >> add to the right waveform graph.

Display the block diagram and then lab view wired the table terminal to the build table express VI. Drag the cursor diagonally until the selection rectangle encloses the build table express VI and table terminal.

Drag the object into the while loop to the right sample compression Express VI.

Use the Wiring tool to wire the Mean output of the Sample Compression Express VI to the Signals input of the Build Table Express VI.

Display the front panel >> arrange the controls indicator >> run VI >> click enable switch  >> stop VI 

Experiment with properties of the table by using the Table Properties dialog box. For example, try changing the number of columns to one.  Save and close the VI.

to be continued ...