LabVIEW

Eventually this page will have an introduction to LabVIEW for those who are not familiar with the language. For now, however, is has only links to some LabVIEW code that I have written. All this code comes with a permanent, non-exclusive, royalty-free license for personal and company-internal use. Except for VIs explicitly covered by the GNU Lesser General Public License, an additional license must be obtained before using this code in a product for sale.

Additional VIs (including some formerly from this page) are available as shareware, with a small recommended fee.

Note:
Since Stuffit now handles .zip files, the .sit files have been removed from the site.

Displaying Compared Digital Waveforms
Enhanced Running Global
Unnecessary Coercion Dots
Edit Panel Elements
A GUI Prototype
Color Palette
GUI as SubVI

Displaying Compared Digital Waveforms

This VI is an example of a way to implement a display comparing two digital waveforms similar to that in SignalExpress. It is written in LabVIEW 8.6 but can be converted to run in almost any earlier version.

Unnecessary Coercion Dots

(July 8, 2004) My mistake:
Stephen Mercer explained the situation on Info-LabVIEW (July 1). It's an upgrade of two features, not a bug in a third.
Tunnels and shift registers now understand type defs. If you pop up on the state tunnel in a state machine, for instance, to make a constant, that constant will be a type def if you originally defined the state enum as a type def. (Prior to LV 6.1, you'd get an enum with the proper states, but it wouldn't track any future changes in the state enum.) This will eliminate a lot of grief that state machines used to give me.
Complementary to this new ability, coercion dots were enhanced to indicate type def to non-type def connections. With the two changes, the wiring at tunnels and shift registers doesn't appear any different, but it really has changed significantly under the surface.
Property nodes do not yet preserve "type def"ness. Hence the new dots.

In working with LV7, I've occasionally gotten coercion dots where I didn't expect them while trying to set type def cluster values through a reference. In a complex application it is easy to overlook something I did wrong, so I've built a simple example where (I think) there is no place for an error to hide.

The example below was made by taking a simple numeric and a simple (non-latching) boolean from the palette, saving them as type defs, popping up on the terminals to create property nodes and references, and wiring them as shown. I can see no reason for the coercion dots. Disconnecting from the type defs makes them go away. The dots appear in LV7.0 and 7.1, but not in earlier versions.

I'm on a Mac running OS X. Does this same problem exist under Windows? Anyone know why it happens? If you'd like to try it on your machine, you can download the .llb (LV7.0) I used. I'd appreciate any information you have.

Edit Panel Elements

Bug fix:
February 26, 2004 - Really checks most recent panel with focus first.

Need to:

make selected front panel elements match in width or height without LabVIEW 7?
access a given decoration programmatically?
make boolean controls and indicators match in various attributes?

Learn about this temporary stand-in for a candidate OpenG package.

A GUI Prototype

A client needed a GUI front end for his simulator of Erbium Doped Fiber Amplifier designs. Learn how developed a LabVIEW 4.0 prototype that supported closed loops in only 23 billed hours.

Color Palette

Addition:
November 16, 2009 - LabVIEW 8.5 version.

Correction:
July 21, 2004 - More accurate color values. Cleaner diagram.

LabVIEW 6.0 introduced several new color palettes. While they are nice, many denizens of Info-LabVIEW (myself included) miss the old palette. If you're among those who miss it, here is a reasonable facsimile. I can't figure out how to use it while editing icons. If you do, please let me know. Each file contains the same VI; just choose whether you want it compressed or not in LV 6.02 or in LV8.5.

Color Palette.vi (42 kbytes)
Color Palette.zip (15 kbytes)
Color Palette 85.vi (21 kbytes)

GUI as SubVI

While the following VIs have been written for different projects over the course of the years, they were assembled and updated for a presentation entitled GUI as SubVI for the September 9, 1999, Power LabVIEW Users Group meeting in Woburn, MA. If you were not at the meeting and want to download a full set of the VIs choose:

GUIasSubVI.zip (903 kbytes).

(Except for Desktop.vi, the VIs are platform independent. Desktop.vi determines which of three operating systems has called it and behaves almost appropriately. I have recently been informed that the user currently logged in needs to be included in the NT style platforms.)

Individual VIs are also available in compressed and raw .vi form, as shown in the table below. If you were at the meeting and want to add the files omitted from the "Goodies" disk, download the first three or four files: Adjust Phase, Capture Board Data, Classify Pits, and, optionally, Run Control Panel. If you are just looking for some nice utilities, you may be interested in the following:

Scalable Delay is my Inline Delay.vi with a fast-forward/slow-motion adjustment added for presentations. It can be used to force a delay at a certain point of a diagram's execution. The default action is identical to Inline Delay.vi, so it can be substituted for Inline Delay.vi.
Chained Find First Error inserts the full calling chain to a subVI error into an error cluster (in the same way as LabVIEW reports it for a function error). It also handles single error code inputs (a convenient way to form error clusters) or arrays of error codes, as Find First Error.vi does. You'll also need its subVI: Call Chain with Arrows. These VIs are included for those who need the LabVIEW 5.0 version. There is much more functionality in their drop-in replacements in the new error handler package.
Post It allows messages from any number of subVIs to be viewed in one convenient place. This VI calls Chained Find First Error.vi.
Desktop returns a path to the desktop in MacOS, Windows 95, or Windows NT. This VI calls Chained Find First Error.vi.
Get Spreadsheet Contents locates the specified spreadsheet text file within the specified folder and returns its content in a table.
File Must Exist stops execution if the specified file can't be found.
Find Data Block extracts one column of a table and returns a pointer to the next blank line in that column. This is especially useful for parsing spreadsheet files.
Was Never Executed returns the value TRUE the first time it is executed after being loaded and FALSE every time thereafter. This VI is reentrant, so it can be used independently in multiple locations.
Toggle changes its outputs between TRUE and FALSE each time it is called.
Running Global allows a system to be stopped from any one of a number of VIs. The LabVIEW 7 version allows automatic stopping on errors.

For examples of how the above subVIs are used, download the whole package.

If you're looking for a specific VI, choose the appropriate link below.

Downloadable Files and Sizes
		.zip	.vi
Missing from floppy	Adjust Phase	17k	58k
	Capture Board Data	19k	65k
	Classify Pits	26k	91k
	Run Control Panel	15k	47k
	Scalable Delay	18k	64k
VI/subVI	Chained Find First Error	35k	117k	Consider upgrade
VI/subVI	Call Chain with Arrows	24k	86k	Consider upgrade
	Post It	36k	125k
	Desktop	22k	75k
	Get Spreadsheet Contents	12k	37k
	File Must Exist	14k	42k
	Find Data Block	12k	37k
	Was Never Executed	5k	14k
	Toggle	6k	16k
	Running Global	7k	21k	Enhanced (LV7)

If you download the LabVIEW VI or control files themselves, you will have to edit their titles to replace each %20 with a space. If they don't automatically associate with LabVIEW, add the MIME types application/x-labview-vi and application/x-labview-ctl (and probably application/x-labview-llb) to your browser's helper files list.