Synchronous digital output on two lines NI USB-6221

[oign]

Dear Labview Community,

I am trying to output digital waveforms on two lines of my  NI USB-6221 . So far I made a vi that seems to run fine with a virtual device.

Though when i try it on the real DAQ it is getting stuck in the while loop because the DAQmx is done task returns a false value to the stop of the loop.

This is a bit weird since like I said it works fine with a simulated device. Maybe someone has a suggestion what I did wrong?

Thanks!

oign

[Wetzer]

Hello,

from the Screenshot i can see, that you use AO Sample Clock to drive your buffered Digital Output Task.

The AO Sample Clock doesnt run by default. You will have to create a "dummy" AO Task, configure this Sample Clock and Start the Task.

Since there is no Sample Clock running "Is Task done" will return False forever.

You can do a little Test to prove this:

Select AI Sample Clock in your VI instead of AO Sample Clock

Open MAX and start a Finite Analog Aquisition with Sample Clock configured and the same number of Sampels configured than your DO Task

Start your VI first then start the Aquisition in MAX

Best Regards!

Moritz M.