LN,
After taking a quick look at your program, I assume you are referring to the fact that you can't enter a value greater than 10 sec into the "Measure Time (sec)" control.
This should be an easy fix for you. With the program not running, right-click on the Measure Time control and select Data Range... from the popup menu. On the data range dialog that appears you will see that this control has a maximum value of 10.0 specified. Change this value to your desired maximum acquisition time and hit OK. You can now enter values up to your new maximum.
If you have any more questions, let me know.
Good Luck,
Scott Menjoulet