Sending two sets of data to simultaneously output on two channels...

[taipan]

LabView 8.2
PCI-6115 Card

I am attempting to output voltage defined by two 1D arrays of doubles (each 250,000 points) from a PCI-6115 card. Each array needs to be output on a separate channel (DAC0 Out & DAC1 Out) so I entered ac0:1 but now need to know how to "feed" these two arrays into the one DAQmx write object. So far I have tried sending them as a single 2D array, a single 1D array (concatenated), and joined as a cluster, and nothing seems to satisfy DAQmx write. The DAQmx write object is set as a "Analog 1D DBL 1 Channel N-Samples" type. I am feeding these same two arrays into a front panel graph to verify the validity of the data (it looks good). I have also successfully output both of the arrays (to an oscilloscope) one at a time over a single channel so I know I am missing something simple here. These two arrays will be output continuously (only updating when the user makes changes to the front panel) at the full speed of the card (2.5 Million samples per second per channel) for maximum resolution. Any help would be appreciated and any other information required is available on request.

If anyone can tell me how to combine my two arrays of doubles, send them to a DAQmx write, and have them output on two different channels, I would be greatly appreciative...

Thank you,

taipan

PS - This is my first experience with LabView so insider lingo may be lost on me...

[johnsold]

Try Analog 2D N Channel N Sample. You have 2 channels but the VI you selected is for one channel. Then use the Build Array function to create a 2D array of your data.

Lynn

[taipan]

Thanks johnsold...

I ended up having to use a DAQmx Configure Output Buffer in the train of DAQmx objects as well to avoid a buffer underrun, but the VI now runs without failing.

My next task is phase locking both waveforms to an input clock signal rising edge... Hopefully I don't run into any more show stoppers!

Thanks again,

taipan