Can I get better time resolution than 1ms in labview?

[jbrookover]

Hello,

I am trying to generate an external waveform which requires timing to be in the microsecond range, I was trying to use the wait function to define the timing dt but found that I could not get below 1 ms. I tried to specify timing in the microsecod range by overloading the wait function with a float (0.200) to represent 200 us but found behavior to be erratic. Again, I am trying to create a waveform for extenal hardware which does not support buffering and requires software to drive.

Thanks!

Joel Abdullah

[waldemar.hersacher]

Under Windows you cannot do any reliable timing below 10 ms.

If you are realy forced to do the timing in software you can switch to LV RealTime and an PXI Realtime controller.

Use a timed loop instead of a wait where you can get microseonds on a PXI Realtime controller.

You must be sure that your external hardware can be accessed from LV Realtime.

[Ben]

"I am trying to create a waveform for extenal hardware which does not support buffering and requires software to drive."

Sorry but that simply can not be done in a Windows environment due to the limitaions of the OS (1KHz was "way-fast" when WIndows replaced DOS).

It can be done in a Real-Time OS like Pharlap for example.

Attempts to deterministically perform any operation at a rate faster than 1KHz in a non-deterministic OS can be best described as an "exercise in futility."

Trying to help,

Ben

Note to Waldermar:

Timed loops can perform rather well at 1KHz or even better if you have a hardware clock available.

Message Edited by Ben on 05-28-2008 10:47 AM

[jbrookover]

Oi,

I had a pit of the stomach feeling that was the case.

I love it, my computers clocking at 3 Ghz but the but the fastest time I can rely on is 100 Hz.

Incredible.


Thank you
Joel Abdullah

[Ben]

Have you tried using a timed loop to get down to 1KHz?

Provided your device can take updates that fast and your code is structured well, 1KHz may be possible.

Ben

[jbrookover]

Yes I just coded up 1 kHz, my sinusoid is compressing and decompressing,dropping out values etc.  Using THD as a quality indicator my 100Hz waveform is acceptable.