What type of signals are you using for the control and feedback? Are you using the analog output for control and the analog input to measure the position? If so, you can configure the board to perform both operations simultaneously, even using the same clock for input and output. This way you can overlay the stimulus data from the analog output, with the acquired position data from the analog input and see the response of your device. We have several examples that show how to do simultaneous AO/AI. Take a look at the link below for one example.
http://zone.ni.com/devzone/explprog.nsf/6c163603265406328625682a006ed37d/913e26ccf1019bbb862566eb007bb202?OpenDocument
Regards,
Brent R
Applications Engineer
National Instruments