Hi sal2,
The DAQmx Base driver installs various LabVIEW examples. You can find them by going to Start (from Windows) >> Programs >> National Instruments >> NI-DAQmx Base >> Examples >> LV7.1 >> Dynamic. An example you can use is in the Dynamics folder, called "Gen Mult Volt Updates - SW". You can change the data being output to vary between 0 and 4 instead of the current sinusoidal data to achieve a software timed pulse train.
Thanks,
Lesley Y.