Darren's Weekly Nugget 06/15/2009

[Darren]

One of my favorite features of LabVIEW 8.6 is Linked Tunnels.  I can't believe I haven't written a nugget about these yet!  In case you haven't heard, wiring tunnels in multi-frame structures is a lot easier in LabVIEW 8.6:

See those tiny white triangles on outer edges of the string tunnels?  Those indicate the input/output tunnels are "linked".  There are two equally awesome use cases for linked tunnels:

1. You are adding a new pass-through wire on an existing case or event structure that already has a bunch of frames.  When you pass the wire through one of the diagrams, if you right-click the output tunnel you just created and choose Linked Input Tunnel > Create & Wire Unwired Cases to link the input and output tunnels that bookend that wire, it will automatically wire up those tunnels in every other frame of the structure.
2. You are adding a new frame to an existing case or event structure that already has linked tunnels.  When you add the new frame, all linked tunnels will already be wired together on the new diagram.

I like this feature so much, I tried to figure out a way to show it off in my NI Week 2008 keynote demo.  But since Tim only gave me 10 seconds to write my VI, I wasn't quite able to squeeze it in.  😉

Message Edited by Darren on 06-15-2009 04:54 PM

[smercurio_fc]

Neat. From what I read about JKI's Right-Click Framework, one of its plug-ins does something similar. It seems, though, that the native LabVIEW solution adds the wires as you create the new cases whereas the RCF plug-in is more manual.

[MattBradley]

I like it!  Now if only I can remember to use it (while I'm programming something, not after I'm done).

[jcarmody]

One of the first things I do when starting a new JKI State Machine based program is to link the tunnels in the While Loop and Event Structure.  Two great tastes that taste great together!  Linked tunnels are great.

[falkpl]

Way cool!  I use "action engine" functional globals all the time, and these are always growing in their case structures, each time I added a case I had to wire up all tunnels through from my shift registers (typically 2-3 wires), or duplicate a default case and alter it.  This takes 10-20 seconds but I do it several times a day.  Now I will be able to save a minute or two a day, at the end of my career I can probably retire a few days early now.  Thanks.

[Ray.R]

Fantastic!

This is a great feature that I was not aware of.  Thanks Darren.  🙂

Using this feature when creating State Machines or Event Structures will be very useful and highly appreciated.

You should definitely show this during NI Week.  This is a feature that has been long awaited....  (by me)

RayR

[Ben]

I am a fan of the linked tunnels myself.

Q: What happens to a linked tunnel when a LV 8.6 VI is back saved to LV 8.5 where that option was not available? I did not notice any warning message when I back-saved.

Curious,

Ben

[Darren]

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Ben wrote:

Q: What happens to a linked tunnel when a LV 8.6 VI is back saved to LV 8.5 where that option was not available? I did not notice any warning message when I back-saved.

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When you save for previous an 8.6 VI with linked tunnels, the links simply disappear in the previous version.  I think we only display warnings during Save for Previous if the resulting VI will be broken, or risks having changed runtime functionality.  In the case of these tunnels, there's no risk of that kind of thing happening in 8.5 and earlier if you remove the links.