Continuous Waveform < 1Hz

[task]

I need to generate a continuous waveform (sine, square, triangle) that is less than 1 Hz. I have tried doing it manually by sending out a 100 point array, one point every X ms based on the frequency setpoint. For example if the frequency is 0.1 Hz I send a point out every 1 ms. The problem I have is I need 0.05 Hz resolution (customer specification). It would be nice to use the Analog output continuous waveform VI supplied with Labview but it doesn't work with anything less than 1 Hz. Any clues?

[Bill B]

Hello,

Thank you for contacting National Instruments.

If you are currently using LabVIEW 7, this can easily be accomplished by using our new NI-DAQmx driver. I have attached an example program that is already setup to do exactly what you want to do. You can find more of these example programs in LabVIEW 7 by going to Help >> Find Examples >> Hardware Input and Output >> DAQmx.

Please take a look at the example I have attached. Depending on the board you have, you may need to decrease the size of the Samples per Buffer from 1000 to a smaller number. If you want to increase your resolution, you can decrease the Cycles per Buffer to 1 or increase the Samples per Buffer or both. If you have any trouble, just reply to this posting. If you do not curre
ntly have LabVIEW 7.0 or a DAQ device that is supported by NI-DAQmx, I can point you to some additional resources.

Regards,
Bill B
Applications Engineer
National Instruments

[task]

Thanks. I think I figured that out but I appreciate your response. One more question...I need to also acquire my analog inputs (8 of them) simultaneously while outputting my waveforms. I'm still working on trying to get one thing to use DMA and another interrupts using the DAQmx stuff. Any help would be appreciated.
Thanks.

[Bill B]

Hello,

Please see this KnowledgeBase and the image attached below. Let me know if you need additional assistance with this issue.

http://digital.ni.com/public.nsf/websearch/C326F7D33CA6DB0E86256DFE008043B7?OpenDocument

Regards,
Bill