In our test there are different steps that use different AO channels. If possible, we'd like to just configure all channels when we start up, and have any unused channels in a particular part of the test output zeros. Is it possible to have an AO task with 16 channels configured, but then only write to, say, channels 4,6,and 10? Or, will we have to have the full array of waveforms, and have 0's waveforms on unused channels?
Since creating the task reserves the channels, and forces them to use the same clock, I'm going to say there isn't a way to do what you are asking. I have been in a similar situation and our solution was similar to what you are describing where we are forced to update all channel values, and have the number of points on all channels be the same.