Digital Start Trigger from an optical switch

[StathPol]

Hi guys, 

Can someone eplain me please how shall I specify which edge (Rising or Falling?) to use for a data acquisition VI? IF the optical switch is connected with an oscope, it has to choose falling or rising. Also, when i use the digital start trigger.vi, shall i input the pulse width of the trigger?

Regards,

[NIRebecca]

Hi,

It may be helpful to have some more information about your program, or an example of the code you have tried so far. There is a lot of online help and documentation of how to use triggering and timing in data acquisition which I think may be a great place to start.

Timing and Synchronization Features of NI-DAQmx: https://www.ni.com/en/support/documentation/supplemental/06/timing-and-synchronization-features-of-n...

Are you using the DAQmx API? I think the Start Trigger.vi you are speaking about is the DAQmx Trigger (VI) in which can you can find all the documentation including how to select rising and falling edge etc. in the following LabVIEW help article.

DAQmx Trigger (VI): https://www.ni.com/docs/en-US/bundle/ni-daqmx-labview-api-ref/page/lvdaqmx/mxtrigger.html#d137e358

I hope this helps give you an idea of where to start. 

[StathPol]

if the trigger is 5 volts, is it possible to say to labview to read 3.5 Volts? because 5 volts at the top edge so my vi works 50% and does not work 50%.