Why the time differece between a timed loop will always be 32ms even I have set the period to be 10ms??

[Guyson]

I'm a beginner of LV,my problem , as u can see from the title, is how to ensure a timed loop to have a period with 10ms?
I have tried many methods but a magic number 32ms always appear?
Can anyone tell me the reason?
Thx a lot!!!

program attached!

[TiTou]

I ran your VI and here is the result I got without changing anything... the loop execute at the rate of 10ms...

Could this come from your PC ? Is it an old slow PC ?

[Guyson]

I use HP notebook (Model nx6120) , 1.73Ghz to run the program and the result is like that

[TiTou]

Hmmm... that's weird ! I tried your VI many times on my computer and it always works as expected

I'll see if I can run it on an old computer. Old the line...

Also, could you try to run the attached VI (in a row.vi) and tell me the result you get ?

[Guyson]

here' sthe result~~
do u think that the problem arise from my notebook??

[TiTou]

... I don't have a clue... ... might be you PC.

The result I get on my computer seems sensible (see attached test_.xls) the first write takes longer because the file has to be created and then it is very fast.

Sorry, I don't understand your results..

[Guyson]

Nevermind, u really help me a lot~~~
But, I still have one more question. I carefully look at ur ok.xls file, i find that not all the difference equal to 10
(e.g. in 44th, 45th and 341st row), why do these happen??

[TiTou]

I have no idea about that either, I almost never use Timed Loops so I don't know how to interpret this.

When it 9 or 11 instead of 10 I assume it is more or less inevitable ; but once it lasts 50ms... I don't know why.
Maybe this won't happen if you increase the priority of the loop.

Sorry, we've reach my limit

[Guyson]

Anyway, Thx a lot~~~
one more question, would u mind telling me the specification of ur computer??

[TiTou]

here it is :

Maybe the details of the hard drive have to be concidered... who knows...

Message Edité par TiTou le 07-14-2006 11:37 AM