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In this section, you will learn about LabVIEW debugging techniques.

If a VI does not run, it is a broken, or nonexecutable, VI. The Run button often appears broken, shown at left, when you create or edit a VI. If it is still broken when youfinish wiring the block diagram, the VI is broken and will not run. Generally, this means that a required input is not wired,or a wire is broken.

Finding errors

Click the broken Run button or select Windows>>Show Error List to display the Error list window, which lists all the errors. Double-click an error description to display therelevant block diagram or front panel and highlight the object that contains the error.

Execution highlighting

View an animation of the execution of the block diagram byclicking the Highlight Execution button, shown in . Execution highlighting shows the flow of data on the block diagram from one node to anotherusing bubbles that move along the wires. Use execution highlighting in conjunction with single-stepping to see howdata move from node to node through a VI.

Execution highlighting greatly reduces the speed at which the VI runs.


Single-step through a VI to view each action of the VI on the block diagram as the VI runs. The single-steppingbuttons affect execution only in a VI or subVI in single-step mode. Enter single-step mode by clicking the Step Over or Step Into button. Move the cursor over the Step Over , Step Into , or Step Out button to view a tip strip that describes the next step if you clickthat button. You can single-step through subVIs or run them normally.

If you single-step through a VI with execution highlighting on, anexecution glyph, shown in , appears on the icons of the subVIs that are currently running.


Use the Probe tool, shown in , to check intermediate values on a wire as a VFI runs. Whenexecution pauses at a node because of single-stepping or a breakpoint, you also can probe the wire that just executedto see the value that flowed through that wire.

You also can create a custom probe to specify which indicator you use to view the probed data. For example, ifyou are viewing numeric data, you can choose to see that data in a chart within the probe. To create a custom probe,right-click a wire and select Custom Probe>>New from the shortcut menu.


Use the Breakpoint tool, shown in , to place a breakpoint on a VI, node, or wire on the block diagram and pause execution at thatlocatiFon. When you set a breakpoint on a wire, execution pauses after data pass through the wire. Place a breakpointon the block diagram workspace to pause execution after all nodes on the block diagram execute. When a VI pauses at abreakpoint, LabVIEW brings the block diagram to the front and uses a marquee to highlight the node or wire thatcontains the breakpoint. LabVIEW highlights breakpoints with red borders for nodes and block diagrams and red bullets forwires. When you move the cursor over an existing breakpoint, the black area of the Breakpoint tool cursor appears white. Use the Breakpoint tool to click an existing breakpoint to remove it.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket 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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