Greetings,
This is extremely easy to do in the LabVIEW environment. If you have LabVIEW, please open the example finder by going to Help->Find Examples. There are a number of examples that ship with LabVIEW which perform analog output with the 6731 board. Try the Getting Started with Analog Output example. You can also find this example online at the following address.
Getting Started with Analog Output
http://venus.ni.com/stage/we/niepd_web_display.DISPLAY_EPD4?p_guid=B45EACE3E33556A4E034080020E74861&p_node=200083&p_submitted=N&p_rank=&p_answer=&p_source=Internal
Regards,
Justin Britten
Applications Engineer
National Instruments