delayed retriggerable finite pulse train

[Little_Tee]

Hi there,

I'm trying to create a delayed retriggerable finite pulse train on a USB-6251 (2 counters). I just read an old thread on this problem and I got it to work.
However, I'm having this one small annoying issue:

• I want to send a finite pulse train (3 pulses) at 1Hz
• The trigger has a period of 3seconds (0.333333Hz)
• My initial delay is 0.1s
• This results in the following :
  
  • first 3 seconds : perfect 0.1s delay, 3 pulses at 1Hz
  • second 3 sec   : nothing
  • third 3 sec        : perfect 0.1s delay, 3 pulses at 1Hz
  • and so on

I reckon this is because the counter that is gating the continuous pulses is not finished yet with his pulse and therefore does not "see" the new rising edge of the trigger.
Is there a way I could solve this?
I know I could just use the first trigger and send 150 pulses or so at 1Hz. That's what I would do if I was very confident in the accuracy of the 3s period of the trigger, but I'm not. And since it is very important the timing is accurate after that trigger, I think I will induce to much error in the timing that way.

Any ideas?

Cheers,
Tom
  

[Little_Tee]

please?

If some things are not clear, do ask me for more info!

[Little_Tee]

Sorry for boosting this thread, but I just noticed something in the program Alan suggested : Delayed_Retriggerable_Finite_Pulse_Train.vi while checking its output on a scope:
If you set an initial delay, the pulse train actually starts after 2 times that delay time after the initial trigger. I can't seem to find where this factor 2 is coming from.

[Little_Tee]

I'm so sorry.
I'm started to get ashamed of myself right now. You can just ignore the previous message. I was using an altered version of that program, one I already had my hands on.
Sorry ... again.