Darren's Weekly Nugget 11/09/2009

[Eric_R]

Hi D*

I am trying to gauge between this behavior seen is the result of a corrupted VI or a corrective action request that we should address here. The disable diagram structure should not effect the rest of the application.Can you provide me with the steps used to cause this error? Do you know if this is caused when the same procedure is followed with LV 2009? If a recompile of the code fixes the issue this points heavily to a corrupted VI.

[tst]

Eric, here's one example of how the CDS doesn't always function correctly (which already has a CAR). That was in 8.6 and I don't know if it still happens in 2009.

[D*]

Eric, I finally have the sequence of events to create the bug.  Use the attached code to reproduce the bug at will in LV8.6.  I'll leave it up to someone else to check 2009. There is nothing fancy to the attached .vis. One should be able to recreate the bug from scratch if they open brand new projects/vis, and add the block diagram elements that you see in the attached vi's.

Instructions.

1. Open both projects (Alpha Project 3.lvproj, Test Project 1.lvproj) into memory.

Setup the correct initial conditions :

2. In the Alpha Project, open "ParentVI.vi" and run it. The indicator should read "Alpha" (this is correct.)  If it doesn't, follow "Repair Instructions" below.

3. Close "ParentVI.vi".  Save any changes that LabVIEW wants.

4.  In the Test Project, open "ParentVI.vi" and run it. The indicator should read "Alpha" (this is correct.)  If it doesn't, follow "Repair Instructions" below.

5. Close "ParentVI.vi". You should get a dialog to save changes to "projectname.vi".  Agree to save changes.

All VIs are now closed.

Create the error.

6. Open "ParentVI.vi" in the Alpha Project.

7. Open "projectname.vi" in the Alpha Project.

8. Run   "projectname.vi" in the Alpha Project.  Indicator reads "Alpha"

9.  Open "projectname.vi" from the Test Project. Indicator reads "Alpha", because we have not run it.

10. Save "projectname.vi" you just openned from the Test Project, and then close that .vi.

11. Close "projectname.vi" you openned from the Alpha Project. (no dialog prompts show)

12. Close "ParentVI.vi' you openned from the Alpha Project.  (no dialog prompts show)

All .vis should now be closed. The projects are still open.

Demonstrate the error.

13. In the Alpha Project, open "ParentVI.vi" and run it. The indicator now reads "Test".  (this is incorrect.)

14. Open the subvi "projectname.vi".

15. Run "ParentVI.vi" again, and voila, the indicator now reads "Alpha". (this is correct.)

"Repair" the error.

1. Open "ParentVI.vi" that shows the bug.  Open it's subvi "projectname.vi".  Save "projectname.vi". Close all .vis. Now you can repeat the instructions to reproduce the bug.

I've notified NI, but I haven't gotten a CAR yet.

 -D

[D*]

Whoops.  There's a typo in item 4.  It should say : "The indicator should read "Test" (this is correct.) "

[Eric_R]

Hi D

Thank you for the instructions, Unfortunately, I was unable to reproduce the error here, I received the correct indicator strings when trying it on my PC and following the instructions. Were you able to hear back form NI in regards to a CAR number?

[D*]

Eric, what version of LabVIEW are you using?  I gave it a try in 2009, and it appears that the bug has been fixed.