Triggering on a external source

[zo fluke]

We are trying to trigger our anolog signal from an external busy signal coming from our spectroscopy amplifier.  We have tried using a triggering node but haven't had any luck (see attached). any ideas?

-Thanks

lkersti@udallas.edu

[GarPar]

Hi zo fluke-

     When you say you haven't had any luck using the triggering node, what do you mean?  Are you receiving any errors?  I am assuming your code will just hang, nothing will happen because you aren't receiving a trigger, correct?

     What DAQ device are you using?  Also, is this busy signal coming from the spectroscopy amplifier a true digital signal? 

     All the best!

[zo fluke]

We are using 6016 NI-DAQpad.  We actually are not getting any errors, our program will run but our data is not triggering propperly.  It will trigger even if I unplug the busy signal.  I'm pretty sure that the busy signal is not a true digital signal. 

 This is the definition given in the manual.

BUSY Rear-panel BNC connector with Zo <10 W provides a
+5 V logic pulse for the duration that the input pulse
exceeds the baseline restorer discriminator.

Thanks again!!

-Zo Fluke

[GarPar]

zo fluke-

     That busy signal description is fairly vague.  Is the busy signal always at zero, or is it floating? 

     It sounds like you might be in a noisy environment.  If your task is starting acquisition when you have specified that it needs a trigger to start acquiring, it somehow thinks it is getting a trigger.  There could be noise in your busy signal line, or even noise in the environment surrounding your DAQpad.  If you have nothing plugged into the trigger line, that line floats around.  It could be collecting voltages from its surroundings, which could cause the trigger to connect.

     You should make sure that the trigger signal being sent to your DAQpad is a digital trigger.  If this busy signal isn't a true digital signal, it may now work correctly for you.

     I hope this helps!