Trigger analog output with analog input using Data Acquisition Toolbox

I am using a national instruments USB 6353 DAQ and matlab's data acquisition toolbox to perform some data acquisition operations. I would like to change from solely collecting data (which works great now) to outputting an analog signal if a specific condition is met in the data collected, in near real time.

pseudo code would look something like this:

create analog input channel

create analog output channel

queue analog output

begin collecting data (this would have to be a background operation, right?)

if(analog input > 2.9v)

     trigger output

end

I just can't figure out how external triggering would work using the data acquisition toolbox, unless it's a manual or immediate trigger.

[W Joey]

Hi Eric, I have met the same problem with you. And i collect input data in a matrix and then compare the value of data to threshold. But i use foreground input and the problem is the comparison will begin only after all data has been collected and it wastes time. Would you like to upload your code?