how to generate two pulses, and use one to trigger the other?

[foolooo]

Hi all,

I had some problems when I wanted to generate a group of pulses. I'm using LV 8.5 under windows XP OS, and the DAQ board I'm using is m series NI-6251 board. I wanna generate a pulse with width about 10 us, and us it to trigger another pulse. The ideal pulses are like

And here is my code,

The scope showed that only PFI4 worked, and there is no response on PFI3, when it ran continuously, SOMETIME both worked, but no stable. Could someone tell me about the problem? Thank you all.

[stilly32]

It looks like you are close. Since you are triggering one output off of the other, you need to ensure that the triggered task has been started and is waiting for the trigger before you start the first pulse that produces the triggering pulse. The easiest way to do that is to either use a sequence structure to ensure that your triggered task's Start is called before the triggering task, or use the error cluster and wire such that the triggered start has to complete first. Also, you won't want to clear your triggered task untill it is complete - otherwise you may clear the task before it can generate a pulse.

Hope this helps,
Andrew S


Message Edited by stilly32 on 04-30-2008 05:31 PM

[foolooo]

Thank Andrew, I connected the error out of the triggered start task to the error in of the trggering start task, and also added a wait in the triggered task, the pulses seemed much better and more stable.

But, there is a wide pulse, more than 1ms, occoured before the triggering pulse, and I have no idea why that happened. Thank you.

Message Edited by foolooo on 05-01-2008 08:36 AM