Creating LabVIEW demonstrations for Connexions1.232003/08/14 13:38:00 GMT-52004/02/12 14:11:04 US/CentralPrashantSinghprash@ece.rice.eduPrashantSinghprash@ece.rice.eduRichardG.Baraniukrichb@rice.eduinteractiveLabVIEWVIThis document explains how authors can create LabVIEW demos and use them in Connexions documents.
One can use LabVIEW 7 to create interactive or animated
demonstrations for use in a Connexions document. These
demonstrations are known as LabVIEW Virtual Instruments or
VIs. These demonstrations currently run outside of the browser
and require the user to have two extra tools: the LabVIEW 7
Run-Time Engine and the Connexions virunner helper
application. Another document
instructs users on how to obtain these tools for their platform.
Here is one such LabVIEW demonstration. It lets the user see
the effects of the amplitude, complex frequency, and phase on
the complex exponential.
Creating VIs
Create a VI using LabVIEW 7 on your favorite platform. If you
create and use sub VIs in your demonstration, then package
these dynamic VIs with the top-level VI into an LLB file. A
convenient way of doing this is by choosing Save with Options
from the File menu. You can then choose Development
Distribution, and when prompted, enter a name for an LLB file
in which to save the VIs.
When the VI has the desired functionality, you will want to
ensure that it behaves the way a user will expect. There
should be a convenient way of choosing to close the front
panel when the VI has served its purpose. The appearance of
the window should also be that of a demonstration applet. You
can set the window appearance by choosing VI Properties from
the File menu and selecting the Window Appearance
category. Choose to customize the appearance, and deselect the
following items:
Show menu barShow scroll barsShow toolbar when runningAllow user to resize windowAllow run-time shortcut menus
If you require scroll bar functionality, or if the VI resizes
well, then you can select the relevant options.
Building Executables
Once you have put the finishing touches on the VI, you will
need to build executables for each supported
targets. Connexions currently supports Windows, Linux (x86),
and Solaris (Sparc) platforms. If you do not have the LabVIEW
7 Professional, then you may need an add-on that provides the
application-building functionality. You will need access to
LabVIEW on each of the supported platforms because we do not
currently have an automated build process.
On each platform, choose Build Application or Shared Library
from the Tools menu. The VIs must not be in memory when you
build them. LabVIEW will warn you if they are. Specify a
target file name for the compiled VI. On Windows, this should
end in .exe. Linux and Solaris do not require
specific extensions for executables, so you may want to append
_linux or _solaris as appropriate to
avoid file name conflicts. Choose a destination directory and
specify the same directory as the support file
directory. Choose the Source Files tab and add the top-level
VI and any dynamic VIs to the list. If you are using dynamic
VIs, then all of your VIs are likely located in an LLB file.
Click the Build button to build the executable. LabVIEW will
place the executable and any shared libraries it calls in the
destination directory. You may save the build options in a
build script so that the process will be easier next time you
create an executable from this VI. To load a saved build
script, click the Load button.
Adding the demonstration to Connexions
Once you have created the executables, anyone with LabVIEW or
the Run-Time Engine on those platforms can run them. But
making the VI Connexions-friendly requires a couple of other
small steps.
You must take all of the files created when you built the
executables, as well as the source VI or LLB file, and add
them to this document. The ID of this document is m11601. To
improve the user's experience, we provide only one link for
running the VI. The virunner helper app then reads the file
pointed to by this link, downloads the platform-specific
files, and runs the VI. The file read by virunner is known as
a VI Information File (viinfo file) and is a simple XML file,
which indicates the locations of the necessary files for each
platform. For the Connexions project we prefer that these
files reside in this document you are currently viewing. The
viinfo file should then point to files inside of this
document.
Once the files are all in document m11601, you must create the
viinfo file. The FORMAT file included with the virunner source
describes the format of the viinfo file. You can access the
virunner source via the CVS web interface at http://mountainbunker.org/cgi-bin/viewcvs.cgi/software/virunner/. Here
is a sample viinfo file: windows
http://cnx.rice.edu/content/m11601/latest/common_distributions.exe
http://cnx.rice.edu/content/m11601/latest/lvanlys.dll
linux
http://cnx.rice.edu/content/m11601/latest/common_distributions_linux
http://cnx.rice.edu/content/m11601/latest/lvanlys.so
solaris
http://cnx.rice.edu/content/m11601/latest/common_distributions_solaris
http://cnx.rice.edu/content/m11601/latest/lvanlys.so
http://cnx.rice.edu/content/m11601/latest/Common_Distributions.vi
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You
should also add the viinfo file to this document so that
others can easily use your LabVIEW demonstration in their
documents.
Using a demonstration in a document
After adding a demonstration to Connexions, you can use it in
a Connexions document. You will need to add the source VI or
LLB file as well as the viinfo file to the document. You can
then then use an example and media tag to present a LabVIEW
demonstration example element.
To produce the following example,
Here is one such LabVIEW demonstration. It lets the user
see the effects of the amplitude, complex frequency, and
phase on the complex exponential.
use this CNXML code:
Here is a sample LabVIEW demonstration. It lets the user
look at various probability distributions and see the
effects of the parameters.
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