It is a very simple task. As I wrote it has nothing to do with a Mills, Lathes etc. The Mach3 is going to run in a minimzed Window, no commands will be entered directly into the Mach3 SW. My UI, Control System, Vision System and Motion System is written in C# using MS VS. At one point, I need to teach setpoints for the stepper motors (4 of them). They are used for a timing belt driven loading system. The accuracy of this system has to be better than 0.1mm. In the past I used motion controllers which are unfortunately not available anymore. This lead me to use Mach3 with a CL stepper driver running in 12800steps/rev microstep-mode. So far, so easy. Now, for teaching the positions, I am using standard buttons on a screen. Actually the mousedown event is used to send a G1 code to mach3 which will start a move to the max possible position. If the button is released, the Mouse_Up event is used to send a Stop using OEMButton 1003. This is working, but there is always a delay until the motor stopps. It is not the ramp down of the movement profile. Therefor I thought the JogOn/Off would be a better way to do this.