Synchronizing 2 DO channels

[santo_13]

Please refrain from creating duplicate posts - https://forums.ni.com/t5/LabVIEW/Synchronizing-2-DO-channels/m-p/4275962#M1246507

[GerdW]

Hi hobbes,

no need for duplicate threads! (I merged them.)

And no need for crying out so loud…

[hobbes8000]

Thanks a lot for your reply.

Best choices for #8 depend on what happens *outside of* the part of the timing diagram you've sketched.   Does something trigger the t=0 point?  What happens after the 100 msec pulse width?   Will you repeat the 2 pulse pattern sometime in the future?  When?  Is is based on a defined delay, a hardware trigger, or a software decision?

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Currently, nothing triggers the t=0 point. After the 100 msec pusle width, the signals are just turned off. These pulses will not be repeated in the future. I want to trigger these pulses by a software decision, such as a start button or something.

I would be really thankfull if you could provide an example of the steps 5~7 you have recommended.

Thank you once more for your kind and detailed reply.

Yoo

[ZYOng]

Here is an example I modified from NI-DAQmx: Correlated Digital I/O with NI CompactDAQ and LabVIEW. The CO will keep providing the sample clocks to the DO task. The DO task will output a pulse of specified width when you press the Send button.

I used simulated devices as I don't have access to the real hardware. Don't forget to configure your RTSI.

[Kevin_Price · Accepted solution]

I kudo'ed ZYOng's example and am adding one of my own.  While there are a few similarities, our approaches are mostly pretty different.  See what you can learn by trying and studying both, then come back if you have questions about specific details.

-Kevin P

[hobbes8000]

Thank you both for your wonderful vis. I really appreciate it.

I have one more question

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Do I have to use a NI RTSI cable? Can't I just use another non NI 34-pin ribbon cable instead? I'm asking because it takes so long for the shipping of the NI RTSI cable. Will there be any problems using a non-NI 34 pin ribbon cable?

* non NI ribbon cable means just a 34 pin ribbon cable that is not manufactured by NI.

Thank you again for your great reply.

[hobbes8000]

I'm actually trying to add more channels from the two daq devices: daq 1, daq 2. But it seems like when trying to add more channels from the same daq device, an error occurs.

what should I do? Can more channels be added using this type of code?

Thanks again for your effort. It's really helping me

[ZYOng]

A port is a collection of digital lines and it works as a single entity. Use browse or syntax to select multiple lines from the same port in a single task.