| Creating Sub-vi's in LabVIEW |
Creating Sub-vi's in
LabVIEW
In any programming
environment, if you do enough programming you will eventually want to put
together code for common tasks and use it as a subroutine or a function (or
whatever other name is used for that in the particular programming
environment). You can do that in LabVIEW. Here's how.
Choose the code that you want
to "encapsulate", and select it. (It has to be the active selection.) With the block diagram
selected, on the menu choose Edit - Creat Sub
vi. The code you selected will be
replaced by a sub-vi. You will probably need to
edit the connections to the sub-vi - i.e. the inputs and the outputs. The sub-vi comes with an icon
- shown in the top-right hand corner of both the front panel and the block
diagram for the sub-vi.
The icon also contains
information about connectors (terminals for information flowing into the
sub-vi and out of the sub-vi, i.e. inputs and outputs). The icon may come
with a single connector terminal, but you can right-mouse-click the icon to
put it into a connector-editing mode to add connectors. With a little
experimentation, you can learn to adjust the configuration. To wire a connector, you will
need either a control (for an input) on the front panel, or an indicator
(for an output) on the front panel. You can create those from the block
diagram. To wire an output, for
example, click on the terminal location on the icon (which will then turn
black) and then click on the indicator (which will turn the terminal
location the proper color for the kind of variable you have in the
indicator). Wire all of the inputs and outputs. Save your sub-vi. To use a sub-vi that
you have created, click on the Select a vi...
icon, then find your sub-vi file and select
it. You will get an insertion icon that you can use to place your sub-vi
whereever you want it in your new program.
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