PWM Signal generation Using Digital I/O of PXI 6509

[Padilam]

Hello 

I need to generate PWM Signal using the Digital I/O of PXI - 6509 in CVI.Please help me in this regard.

What are the things i need to consider.

Regards,
Srinivas Padilam.

[R Sandoval]

Hello Srinivas,

Please refer to the forum link (http://forums.ni.com/t5/LabWindows-CVI/pulse-signal-in-cvi-whith-NI6221/m-p/1072125).  The posted reply has an example of how to generate a PWM signal using DAQmx in CVI.

[Padilam]

Ramon,

For the example above they are using counter channel of the 6221 card but i need to generate 20 PWM. so i need to use Digitial Output lines.

Thanks,

Srinivas Padilam

[R Sandoval]

Hello Srinivas,

A counter is particularly useful in setting the clock frequency for the production of PWM signals.  An example of this can be referenced at:

NI-DAQmx: M Series Pulse Width Modulation (PWM)

http://zone.ni.com/devzone/cda/epd/p/id/5043

However, the PXI-6509 does not have a counter and does not provide a PFI line for external trigger sources.  Therefore, the production of PWM signals on this card will have to be software-timed.  A related example can be referenced:

Software Timed Pulse Width Modulation

http://decibel.ni.com/content/docs/DOC-7198

The example is structured for the production of only one PWM signal.  Since you are using multiple lines, my best suggestion is having a loop that executes without time delay and updating the values of the DIO based on elapsed time.  You may, however, encounter limitations with this implementation since your while loop may possibly execute every 1 ms.