Jump to content

"Continous Pulse Train" Output - PWM Control with Duty Cycle


Recommended Posts

Alright, so the latest project is to drive a throttle body type valve with Pulse Width Modulation (http://en.wikipedia.org/wiki/Pulse_width_modulation). I have a number of PCI cards to choose from (using PCI-6123 counter 0), and am able to correctly run my valve through MAX. I'm having trouble running a VI and controlling the duty cycle through it.

The valve needs to be driven at 128 Hz and varying duty cycle between 5% and 95%, which I've tested through MAX and it works great. The attached VI will run the valve, but it won't update: so I can input a duty cycle, run the VI and it will move to the requested position, but when I change the duty cycle in the front panel control it doesn't change the valve position or the PWM output. I have any test tools available if they're needed, but this looks to be a problem with my understanding of how to control a counter's output duty cycle in a VI. Any ideas?

Available hardware devices are (if you have something against using a 6123 for some reason):

PCI-6122

PCI-6123 (currently using ctr0 and works fine)

PCI-6601

cRIO:

9211

9481

9481

9203

9265

9411

SCXI: (Can't use, too slow)

1102B

1102B

1520

1124

1520

Gen_Dig_Pulse_Train-Continuous-Variable_Freq_LV86.vi

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.