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Practice debugging techniques.

Complete the following steps to load a broken VI and correct the error. Use single-stepping and execution highlighting to stepthrough the VI.

Front panel

  • Select File>>Open and navigate to C:\Exercises\LabVIEW Basics I to open the Debug Exercise (Main) VI.The front panel shown in appears.
    Notice the Run button on the toolbar appears broken, shown in , indicating that the VI is broken and cannot run.

Block diagram

  • Select Window>>Show Block Diagram to display the block diagram shown in .
    The Random Number (0-1) function, located on the Functions>>Arithmetic&Comparison>>Express Numeric palette, produces a random number between 0 and 1 .The Multiply function, located on the Functions>>Arithmetic&Comparison>>Express Numeric palette, multiplies the random number by 10.0 .The numeric constant , located on the Functions>>Arithmetic&Comparison>>Express Numeric palette, is the number to multiply by the random number.The Debug Exercise (Sub) VI, located in the C:\Exercises\ LabVIEW Basics I directory, adds 100.0 and calculates the square root of the value.
  • Find and fix each error.
    • Click the broken Run button to display the Error list window, which lists all the errors.
    • Select an error description in the Error list window. The Details section describes the error and in some cases recommends how tocorrect the error.
    • Click the Help button to display a topic in the LabVIEW Help that describes the error in detail and includes step-by-step instructions forcorrecting the error.
    • Click the Show Error button or double-click the error description to highlight the area on the blockdiagram that contains the error.
    • Use the Error list window to fix each error.
  • Select File>>Save to save the VI.
  • Display the front panel by clicking it or by selecting Window>>Show Front Panel .

Run the vi

  • Click the Run button to run the VI several times.
  • Select Window>>Show Block Diagram to display the block diagram.
  • Animate the flow of data through the block diagram.
    • Click the Highlight Execution button, shown in , on the toolbar to enable execution highlighting.
    • Click the Step Into button, shown in , to start single-stepping. Execution highlighting shows the movement of data on the blockdiagram from one node to another using bubbles that move along the wires. Nodes blink to indicate they are readyto execute.
    • Click the Step Over button, shown in , after each node to step through the entire block diagram. Each time you click the Step Over button, the current node executes and pauses at the next node.Data appear on the front panel as you step through the VI. The VI generates a random number and multiplies itby 10.0 . The subVI adds 100.0 and takes the square root of the result.
    • When a blinking border surrounds the entire block diagram, click the Step Out button, shown in , to stop single-stepping through the Debug Exercise (Main) VI.
  • Single-step through the VI and its subVI.
    • Click the Step Into button to start single-stepping.
    • When the Debug Exercise (Sub) VI blinks, click the Step Into button. Notice the run button on the subVI.
    • Display the Debug Exercise (Main) VI block diagram by clicking it. A green glyph, shown in , appears on the subVI icon on the Debug Exercise (Main) VI block diagram, indicating that the subVI is running.
    • Display the Debug Exercise (Sub) VI block diagram by clicking it.
    • Click the Step Out button twice to finish single-stepping through the subVI block diagram. The Debug Exercise (Main) VI block diagram is active.
    • Click the Step Out button to stop single-stepping.
  • Use a probe to check intermediate values on a wire as a VI runs.
    • Use the Probe tool, shown , to click any wire. A window similar to appears.
      LabVIEW numbers the Probe window automatically and displays the same number in a glyph onthe wire you clicked.
    • Single-step through the VI again. The Probe window displays data passed along the wire.
  • Place breakpoints on the block diagram to pause execution at that location.
    • Use the Breakpoint tool, shown in , to click nodes or wires. Place a breakpoint on the block diagram to pause execution afterall nodes on the block diagram execute.
    • Click the Run button to run the VI. When you reach a breakpoint during execution, the VI pausesand the Pause button on the toolbar appears red.
    • Click the Continue button, shown , to continue running to the next breakpoint or until the VI finishes running.
    • Use the Breakpoint tool to click the breakpoints you set and remove them.
  • Click the Highlight Execution button to disable execution highlighting.
  • Select File>>Close to close the VI and all open windows.

Questions & Answers

a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
Kim
y=10×
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
im not good at math so would this help me
Rachael Reply
how did I we'll learn this
Noor Reply
f(x)= 2|x+5| find f(-6)
Prince Reply
f(n)= 2n + 1
Samantha Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, Labview graphical programming. OpenStax CNX. Apr 09, 2015 Download for free at https://legacy.cnx.org/content/col11408/1.2
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