Bug by DAQmx PWM output (1Hz, 1%)

[Risotto]

Hello,

I have here a strange problem with PWM generation / DAQmx (PCI 6014, PCI 6229).

I would like to generate a PWM signal herausgeben. To do this I use the DAQmx-driver, which works fine. But I found a strange problem:in some case, when I want to generate 1Hz/1%, i get 6,6Hz and 6,6%. Or when I want 1Hz und 99%, I get 6,6Hz und 93,3%.

After some researchs, I found that the output was depending on how I initialize my task and particulary how I create my channel with "Create Channel (CO-puls generation frequency)".

Case 1: (please see in attached file "PWMout_OK.vi")

I init "Create Channel (CO-puls generation frequency)" with 1Hz/1%, and then starts the task. Then I use ich "DAQmx Write" with 1Hz/99% --> I get 1Hz/99%

Case 2: (please see in attached file "PWMout_not_OK.vi")

I init "Create Channel (CO-puls generation frequency)" with 2Hz/1%, and then starts the task. Then I use ich "DAQmx Write" with 1Hz/99% --> I get

6,66...Hz/93,33...%

Seems to be a bug for me. But do I use the DAQmx driver the rigth way?

Regards,

Risotto

Message Edited by Risotto on 04-25-2007 04:19 AM

[Kilian]

Hi Risotto,

Can you please try to insert a "DAQmx Stop Task.vi" and a "DAQmx Start Task.vi" in between the two "DAQmx Write" in your file "PWMout_not_OK.vi"?
Please let me know if the error occurs after inserting these two steps.

regards
kilian

Message Edited by Kilian on 05-03-2007 04:57 AM