How do i create 6 digital 25Hz PWM output signals with my PCI-6221 card?

[RT_1979]

Hi!
I´m a student, who´s trynig to control a gasturbine process for my diploma thesis. The control program should be written in LabView 8. I need to control 6 25 Hz PWM signals for the gasvalves. The  needed accuracy of the duty cycle has to be about  0.1 %.
 A  tech. engeneer from  NI  told  us , that  we can  do this by using one single digital output for each PWM.
Now, after a while, i need to implement it into my program. But there are troubles:
My NI-PCI-6221 standard card only has 2 couteroutputs and only the first of the 3 ports seems to be buffered (Error Nr.  201062)...
I tried to do the programming, by manipulating the "DIO_PWM_50Hz.vi" I found in google.
Does anyone of you have any information or helpful examples how i can create these PWM with my card, or did I get a wrong Information by the salesagent (...not the first time....)?
Thanks for your help

Tobi

[Andre_Saller]

Here you can find an example, how to do this:

http://sine.ni.com/apps/we/niepd_web_display.display_epd4?p_guid=DE27921DB53A4D8DE034080020E74861&p_...

As the text says, best would be to use the counter. As your Hardware has only 2 Counters, you would need additional hardware. Best would be to use a Counter-Card (660x), thes boards have up to 8 counters, so you coulkd control your 6 gasvalves indipendently.

The soultion with the timed digital outputs of the m-series boards would only work, if you can use the same timing (one counter) for all 6 outputs.

Hope this helps!

[RT_1979]

Hello Andre!
Thanks for your help. I already knew the example you sent me. Unfortunately I need to control 4 different timings for my output signals and even measure 2 PWM, so i think i need to get another card.