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Chapter 9
Creating VIs
©
National Instruments Corporation
9-19
Opening, Operating, and Changing SubVIs
You can open a VI used as a subVI from the block diagram of the calling
VI by double-clicking on the subVI icon or by selecting Project»This VI’s
SubVIs. You will see a palette containing all the subVIs of the calling VI.
Select the subVI you want to open.
Any changes you make to a subVI alter only the version in memory until
you save the subVI. The changes affect all instances of the subVI and not
just the node you used to edit the VI.
Activity 9-4. Call a SubVI
Your objective is to build a VI that uses the
Temp & Vol.vi
as a subVI.
The Temp & Vol VI you built in Activity 9-1 returns a temperature and
volume. You will take a volume reading and convert the value to gallons
when a switch is pressed.
Front Panel
1.
Open a new front panel by selecting File»New.
2.
Select a Horizontal Switch from the Controls»Boolean palette and
label it
volume
. Place free labels on the front panel to indicate
Liters
and
Gallons
by using the Labeling tool.
3.
Select a meter from Controls»Numeric and place it on the front panel.
Label it
Tank Volume
.
4.
Change the range of the meter to accommodate values ranging
between 0.0 and 1000.0. With the Operating tool, double-click on the
high limit and change it from 10.0 to 1000.0. Switch to the positioning
tool and resize the meter by dragging out one of the corners and
expanding the control.