I've done the same thing as jimdi4. You can add as much logic as you need to get it to act like you process. I generally use timers to reproduce the real world delays. As to the graphical environment, you can add windows to your HMI to allow you to monkey with the simulation parameters. I use a popup window that I can move out of the way if I need too. I have also done some simulation in the HMI. Namely Wonderware Intouch scripts. If you have any more questions, please ask.