So basically, you need to follow either of the 2 examples:
Generates data in the foreground: http://www.mathworks.com/help/toolbox/daq/bsob84e-1.html#bsob867-1
Generates data in the background: http://www.mathworks.com/help/toolbox/daq/bsob84e-1.html#bsob885-1
With analog output, you can formulate your signal, queue it and start analogoutput.
For a step signal, something like:
dataOut = zeros (1,1000);
dataOut(1:200) = ones(1,200)*4.5;
s = daq.createSession('ni');
s.Rate = 1000
s.addAnalogOutputChannel('cDAQ1Mod2',0,'Voltage')
s.queueOutputData(dataOut);
s
s.startForeground();
This will generate a step for 0.2 seconds. You could use continuous generation to reuse the data to continuously generate the same signal.
