Re: More then one active Vi with open Front panel?

[Dave Ritter]

Gerd, Michael, Paul, (others...?)

This sounds like the perfect situation for the "Selective GUI Panel 
Control" technique, whereby all the subVIs can remain embedded in a 
*single* ( -- Michael, you'll like that one ;�), active loop, and the 
GUI panels open and close without any impact to the underlying code. 
All of the GUI subpanels VIs can live inside the single loop 
architecture without the typical wireflow complications of nested while 
loops -- that is, 'outer' main VI loops waiting on the completion of 
'inner', subVI (GUI) loops.

Another one of the great advantages of this method is that it can 
usually be applied to existing architectures without the usual 
hair-pulling, gnashing of teeth, and major reconstruction required by 
changing the application's underlying architecture midstream. (In fact, 
this is precisely how I stumbled onto it myself...)

There isn't room to discuss the concept in any detail here, but if you 
are curious, there are 20 pages or so dedicated to the technique  in 
"LabVIEW GUI" (including a variety of real-world, practical examples -- 
more info here:  http://www.bettervi.com/LV_GUI/LVGUI_Gen.html )

On the other hand, if you don't want to spring the 50 or so bucks for a 
book, check out the LTR back-issues for two articles on the technique. 
(Intro article: Vol. 8 No. 2, and an application to Error Handling: 
Vol. 8 No.3. More info can be found at www.ltrpub.com)

Not only does your situation sound like the ideal application for this 
particular technique, but once you get a handle on the underlying 
concept (and the apparent reversal of LabVIEW GUI logic implied by it), 
you are sure to find other interesting uses for this handy, and (dare I 
say it?) powerful,  wiring strategy.

Cheers,

Dave Ritter
BetterVIEW
www.bettervi.com

Yes, it will work. Go right ahead.

My problem is I enjoy discussions on methodology and implementation 
techniques too much. In our local LabVIEW user group meetings we
sometimes (actualy always) discuss (actually argue) programming style. 
The issue lately is: single loop good, multiple loops bad.
:-)

Michael Aivaliotis
<http://forums.lavausergroup.org>
Couldn't I put the subvi's in a true case and nothing in the
false case within the separate while loops? Control the case
using a local (....aaaah, that bad word again) from the state machine.
Maybe it is not best programming style, but would be quick to
implement in this existing project....
Gerd



How do you suggest that the subvi's get called? What method
would you use to command the subvi's from the state machine?
Just curious...
Michael Aivaliotis

Gerd,

You asked,

...The main VI is basically a state machine waiting for user
clicks to
go to one of the sub VIs, which e.g. displays a xy chart of
measurements... How can I get the main VI to commence working (not
waiting for the chart window to complete and return)?
Michael responded,

You will have to use VI Server to do this...
While Michael's approach will work and is probably
preferable, I think
you might also accomplish the same thing by putting each of your
selectable subVIs in its own loop parallel to the state
machine loop.
Use the state machine to enable the execution of the
appropriate subVI
for one iteration of the subVI's loop. One loop being held up until
its subVI closes will not interfere with any other loop,
including the
master state machine's.

--
        EnWirementally,
        Paul F. Sullivan