SoftToon,
Try this example: http://sine.ni.com/apps/we/niepd_web_display.DISPLAY_EPD4?p_guid=B45EACE3DBEB56A4E034080020E74861&p_node=DZ52146&p_submitted=N&p_rank=&p_answer=&p_source=External.
I found it by searching the Example Code Library for frequency. Good luck with your application.