(DAQmx NI USB 6210) How to export/have access to armstart trigger signal of a counter input if you are triggering it by itself

[FilipN]

Hi,

When carrying out counter input task (edge counting) with my NI USB 6210 device, I use Arm Start trigger with trigger source set to be the same counter input source (so it starts counting edges immediately when seeing an edge after starting the task).

I'm trying to have access to this start edge/signal so that it can be used to trigger another task, but I don't see how to do it.

(I wouldn't consider using another Digital input as trigger for both tasks as it wouldn't tell me the exact time when the edge is arriving.)

Anyone can help me with it? Any advice would be much appreciated.

Attached is a snippet of the part of vi.

[Kevin_Price]

No need to export the signal by functional name.  It's already available by it's wiring designation "/Dev3/PFI3".  Just wire in that same terminal constant value when you configure the start trigger signal for your DO task.

-Kevin P

[FilipN]

Thank you Kevin, (this is actually the same question as the follow up question in the other topic)

I understand what you are saying, but as I have periodic pulses coming into the counter, I don't want the whole original counter input as the start trigger of the DO. What I only need is the very edge which triggered the start of itself (the counter input) so that I can make sure the digital output and the counter task start at the exact same time (at a certain edge of the counter input). Not sure if I can do that with USB 6210?

Hope I made some sense.

Thanks again

[Kevin_Price]

Ok, I gotcha.  I don't think I've ever had to set up something like that.

Poking around in the options for the DAQmx Export Signal property node didn't show anything promising, but I think I found an even simpler answer elsewhere.  It'll be in the DAQmx terminal constant or control you wire into the 'source' input of DAQmx Trigger for your DO task.  You'll need to right click on it and choose "IO name filtering..." from the menu.  Then check the box for "Include Advanced Terminals."   Once you do that, you'll get many more options available for configuring a trigger source, including "/Dev3/Ctr1ArmStartTrigger".   Hopefully that'll do what you need.

-Kevin P

[FilipN]

Hi Kevin,

Thank you for your reply. It does help on devices which allow that specific routing option.

In fact I've found something even more suitable to my task: using a counter output pulse ticks task to generate a pulse with defined number of ticks from counter source input. It then generates a rising edge at the beginning and a falling one at the end and does exactly what I want.

Thanks again for your help, it did open up a new field for me.