RT file I/O hangs timed loop

[Robert_North]

After porting a RT project from LabVIEW 8.5.1 to 2010 I started experiencing issues where after a couple of hours one of 6 timed loops I am using would hang.  This occurred in both debug mode and when executing the built application.  After quite a few hours of debugging I have narrowed it down to a possible problem when using file I/O in timed loops on an RT system. 

I have included an application that contains 2 timed loops one of which is opening/creating a text file, writing some text to this file and then closing the file.  The behavior that I am experiencing is that the timed loop that contains the file I/O eventually hangs.  If this timed loop is changed to a while loop then neither of the loops hang. 

Can anyone confirm whether there is indeed a fault with timed loops in LabVIEW 2010 or whether I a have something wrong with my installation of LabVIEW?

I am currently using LabVIEW 2010 DS2 and NI-RIO 3.5.1 on cRIO-9014 and cRIO-9073.  Both cRIO's show the same behavoir.

Regards,

Rob

[MegaHertz]

Hi Rob,

I've been running your test VI on my computer here (LabVIEW 2010, Windows 7) for a couple hours, and I haven't seen any hang behavior from the file I/O loop. At this point, there are no known issues with Timed Loops in 2010. Do you have any sense of special conditions that might cause the hang?

[jkurtw]

Run it on an RT controller

[Robert_North]

Hi Andy,

Have you tested this on the cRIO-9014 and 9073?  This issue seems to be specific to RT.

Best regards,

Rob

[MegaHertz]

Hi Rob,

Thanks for the re-direct, I was able to reproduce this on a 9073. This was reported to R&D (corrective action request #214156) for further investigation. In the meantime, this Developer Zone on using File I/O in RT may help point towards a workaround for your particular application.

Thanks for the feedback!

[Robert_North]

Hi Andy,

Thanks for your response.  I have already converted all timed loops to while loops which seems to work fine for this app.  Hopefully a patch can be issued soon as we intend to port other RT apps that required timed loops to achieve thread synchronisation, to 2010.

Regards,

Rob