Experimental Physics and
Industrial Control System

I am beginner in EDM and I want to add a button in EDM. When I will press the button then my progam should be start otherwise should not be start. In case of my program, I am going  from 10 mA(i.e. initial value in current source)  to 120 mA(i.e. final value) with step of 10.How to use message button which act as a START button of my program and this should be press(toggle) only one time and program should be proceed and also I want to add stop button so that when press stop then whole program should be stop.How to perform this task ,I have no idea because for loop or while loop does not work in VDCT directly. Please provide example for this type of task.  

Thanks in advance......