Delay, Timer, and Sleep values are wildly off

[ASIC_LabRat]

Thanks,

I found this Automatic Loading of Interface to the Win32 Application Programmatic Interface (API) Import Librarie... with the list of the names but no discription of how to use... I assume there should be a link to the documentation. I suggested this as an Idea to close this loop.

Cheers!

ChipB

[Brian Richter]

Unfortunately I was mistaken; the problem was solved only temporarily. When my computer reboots, the problem is solved for a while. When I run some LabWindows applications, it eventually goes bad, and the timing of my timer callbacks along with Delay() and QueryPerformanceCounter() give wrong answers just as they did before. The Delay() issue I can avoid by using Sleep(), but the timer callbacks are unfixable.

I haven't been able to isolate it more specifically to what the magical function in these applications is that breaks things. I've just been living with the problem because on the true target computer for this application, the problem doesn't occur.

Brian

[D_Biel]

Since you previously fixed this by upgrading the BIOS, I guess you may have seen this KB by Microsoft: http://support.microsoft.com/kb/895980

The Delay and Timer functions in CVI take advantage of the QueryPerformanceCounter and may be subject to this issue. However, if you have already updated your BIOS, then this may not be relevant.

I have also seen a similar issue to this twice before. In one case, it took us two months to discover that it was a bad motherboard. Once Dell replaced the motherboard, everything worked fine. In the other case, the system was heating up causing changes in the performance of the CPU. This one looks like a possibility for your system because you experience the problem after the system has been running for awhile. You could try monitoring your CPU temperature and see if it is within a "normal" range.