Chapter 9 Creating VIs
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National Instruments Corporation 9-21 BridgeVIEW User Manual
How Do You Debug a VI?
A VI cannot compile or run if it is broken. Normally, the VI is broken while
you are creating or editing it, until you wire all the icons in the diagram. If it
still is broken when you finish, try selecting Remove Bad Wires from the
Edit menu. Often, this fixes a broken VI.
When your VI is not executable, a broken arrow appears instead of the Run
button. To list the errors, click on the broken Run button. Click on one of
the errors listed and then click on Find to highlight the object or terminal
that reported the error.
You can animate the VI block diagram execution by clicking on the
Highlight Execution button. Execution highlighting is commonly used
with single-step mode to trace the data flow in a block diagram.
For debugging purposes, you might want to execute a block diagram node
by node. This is known as single-stepping. To enable the single-step mode,
click on the Step Into button or Step Over button. This action then causes
the first node to blink, denoting that it is ready to execute. Then you can
click on either the Step Into or Step Over button again to execute the node
and proceed to the next node. If the node is a structure or VI, you can select
the Step Over button to execute the node but not single-step through the
node. For example, if the node is a subVI and you click on the Step Over
button, you execute the subVI and proceed to the next node but cannot see
how the subVI nodes execute. To single step through a structure or subVI,
select the Step Into button.
Click on the Step Out button to finish execution of the block diagram nodes
and/or complete single stepping. For more information about debugging,
see Chapter 4, Executing and Debugging VIs and SubVIs, in the
G Programming Reference Manual.
For more information about block diagrams, and the options available from
the block diagram window, see the section
