How do I prevent scroll bar use from disabling front panel updates?

[ww.brown]

I have two top-level VIs running simultaneously using different execution systems.  The first VI has a list box scroll bar.  When the scroll bar is used by the operator, updates to the second VI front panel are temporarily blocked.  This is due to the single user interface thread shared by both VIs.  I there anyway to allow the second VI to update its front panel while the first VI is bound to its scroll bar?

[Wiebe@CARYA]

Hi,


Your problem seems to be a bit more complex. I created two vi's, one with a simple loop, the other with a list box (both running in different execution systems). The first isn't noticeably affected by moving the listbox' scrollbar.


It there an increase in processor load when you move the scrollbar? That could stop the other vi from updating. Perhaps you can isolate the problem (remove all irrelevant code) and post the remaining vi's?


Regards,


Wiebe.



"wwwbrown" <x@no.email> wrote in message news:1140801036814-330030@exchange.ni.com...
I have two top-level VIs running simultaneously using different execution systems.&nbsp;&nbsp;The first VI&nbsp;has a list box scroll bar.&nbsp; When the scroll bar is used by the operator, updates to the second VI front panel are temporarily&nbsp;blocked.&nbsp; This is due to&nbsp;the single user interface thread shared by both VIs.&nbsp; I there anyway to&nbsp;allow the second VI to update its front panel while the first VI is bound&nbsp;to its scroll bar?

[ww.brown]

Thanks for your reply.  You're right - there is more to my application.  Based on your letter I just tried a simple example and it works fine.  Something else must be going on in the larger application that gives the appearance of this problem.  I will have to spend some more time isolating it down to a small example.

I'll be in touch and thanks again.

wwwbrown

[ww.brown]

I have narrowed the problem to an example.  With the attached, run x.vi, run y.vi and then use the scrollbar on x.vi.  y.vi will stop updating. 

Regards,

wwwbrown

[altenbach]

They seem to work just fine here. Everything keeps updating. (LabVIEW 8.0).

What is your LabVIEW version?

Why are you opening a new VI reference every second in y.vi, without ever closing any references?????

Did you possibly disable mutithreading? (tools...options...performance and disk)

Message Edited by altenbach on 02-27-2006 12:28 PM

[Khalid]

Doesn't work, i.e., problem reproducible in 7.1.1.   Works fine in 8.0, though.

-Khalid

[wwbrown]

I have apparently stumbled into a resource bottleneck in Version 7.1.  I will be upgrading to Version 8 soon.  Thanks all for your help.

wwwbrown

[Wiebe@CARYA]

Looks like you found a new LV7.1 feature: "Wait For Front Panel Activity Finished".


I found that the same problem exist with other controls, that the scrollbars are not relevant (e.g. just clicking in a string control hangs the loop), and that the open vi ref might as well be in the same loop as the FP clicked on... Even the VI's own scrollbars hang the loop. Also, the path/name of the vi opened by open VI ref doesn't have to be a valid one.


Regards,


Wiebe.



"wwwbrown" <x@no.email> wrote in message news:1141071046028-330877@exchange.ni.com...
I have narrowed the problem to an example.&nbsp; With the attached, run x.vi, run y.vi and then use the scrollbar on x.vi.&nbsp; y.vi will stop updating.&nbsp;
Regards,
wwwbrown



FP Hang.llb:
http://forums.ni.com/attachments/ni/170/170237/1/FP Hang.llb

[ww.brown]

Thanks for the detailed analysis.   I wonder if NI has documented this in their "Known Problems" list for LabVIEW 7.1?

wwwbrown