Depending on the software you are using, there are many shipping examples and example programs on the web that illustrate generating a finite pulse train. The E series boards have the DAQ-STC counter/timer chip, and so make sure you search for DAQ-STC examples. I have included links to a LabVIEW example and Measurment Studio Example in Visual Basic.
Generate finite pulse train in LabVIEW.
http://eagle.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_guid=B45EACE3DA2156A4E034080020E74861&p_node=DZ52328&p_submitted=N&p_rank=&p_answer=&p_source=Internal
Generate finite pulse train in Visual Basic with Measurement Studio
http://eagle.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_guid=B45EACE3D96156A4E034080020E74861&p_node=DZ52328&p_submitted=N&p_rank=&p_answe
r=&p_source=Internal
