Wrong pulse counting for tick based pulse generation for USB6210

[pc@norpix.com]

I try to  generate 50 HZ pulse in USB 6210 with sample code "http://zone.ni.com/devzone/cda/epd/p/id/3088". But doesn't work properly.

Please see attachment:

app.jpg: pluses setting. I set 200000 ticks to low and high.

Tick count based.jpg : result wave  from oscilloscope.

You will see low is 3 times longer than and high.

Do you have any idea?

Thanks.

[USBarnes]

pc@norpix.com,

Does this happen on ctr0 as well? Also, have you tried decreasing the low and high ticks to something more like 1000? I'd like to see if we can get the output to look as we expect. My last question is, what are you using for a trigger source? Have you tried this with a non-retriggerable example? If so, does it output the same incorrect waveform? Thanks for the pictures. Those are always helpful for visualizing the situation.

[pc@norpix.com]

I didn't test ctr0 since It's used by something else.

Trigger  source  is standard TTL signal generated by NI PCI 6601;without trigger  is the same.

[USBarnes]

pc@norpix.com,

Could you tell me more about the trigger signal you are using from your NI PCI 6601? Is it outputting at a particular frequency? My thought is that maybe we are retriggering before the waveform has finished a generating a complete period. It looks like there is one period that looks correct from the original picture you posted. Not to be too repetitive, but did reducing the ticks make the duty cycle correct?