I just finished an experiment about something similar to the one you have. It's a salsa mixer. It has two pumps with a flow meter each one, one low and one high level switch, the mixer motor and the dump motor. It also has the start cycle, stop cycle and the emergency stop button. The system should repeat the cycle as needed. When the stop cycle is pressed, it must finished the cycyle and not start a new cycle until the start cycle is presed again. When the e-stop is pressed, the cycle should stop and when the start cycle is pressed, the cycle should re-start right where it stopped.
If you need more information about it, just let me know.