Computer running LabView loses time

Question

Running LabView VI on HP Brio pc
Computer clock loses time non-linearly
e.g. after 24 hours lost 5 mins, after 36
lost 20mins. Time stamped log file is therefore wrong.
Happens with both Win95 or Win98 OS but worse on Win95.
The VI is reading data from instruments on serial port
and also a GPIB interface. Very slow
logging though (1 reading/min over many days).
Does this look like a hardware or software issue? Has anyone ever experienced this?
Help appreciated

Answer 1

Mine does too - and I can loose an hour in a day! I posted it on
a microsoft newsgroup and they explained that it was my problem,
my application was too cpu bound to service the time interupt
requests. There is no need to reset the time, just reboot. Windows
it seems only reads the time from the BIOS once at startup.
Call it a feature...?
I call it a bug!
"Mark Hanning-Lee" wrote in message news:[email protected]...
> GP wrote:
> >
> > Running LabView VI on HP Brio pc
> > Computer clock loses time non-linearly
> > e.g. after 24 hours lost 5 mins, after 36
> > lost 20mins. Time stamped log file is therefore wrong.
> > Happens with both Win95 or Win98 OS but worse on Win95.
> > The VI is reading data from instruments on serial port
> > and also a GPIB interface. Very slow
> > logging though (1 reading/min over many days).
> > Does this look like a hardware or software issue? Has anyone ever
> > experienced this?
>
> A general points:
>
> Win98 tends to be worse at this than other OS; not just a LabVIEW issue.
> My Win98 PC used to lose minutes per day; my Win2000 PC loses only a few
> ms per day.
>
> Make SURE that every loop in your code has a Wait or Wait until next ms
> Multiple. That frees the CPU.
>
> If a problem gets worse with time, see whether your memory usage is
> growing with time.
> If so, look for Build Array that is running in a loop, causing a large
> array to grow without limits.
>
> Also make sure there is a Close function for every Open.
> Make sure that you aren't opening & closing inside a loop; correct
> behavior is to Open before a loop, Read and/or Write inside the loop, &
> Close at the end.
> That's true for serial i/o, for VISA, and for GPIB.
>
> Lastly, if you are now using classic GPIB & serial functions, consider
> switching to VISA. Or vice versa!
>
> In general, you can keep the clock sync'd by running the free Dimension
> 4 software from www.thinkman.com . That sets the PC clock at regular
> intervals so it stays more or less on time.
> (But I'd be reluctant to do that when the program is running; might mess
> up loop timing.)
>
> Mark