The purpose of this senior design project was to take an ongoing project’s manually controlled water filtration system with no data logging and transform it into an easily configurable automated open-loop process with data logging. Instead of using an off the shelf programmable logic controller, a Raspberry Pi was chosen to act as the master controller and data logger. This choice enabled easier end-user human-machine-interface, convenient data log accessibility, and a wide variety of future expansion opportunities. The physical system being controlled consists of three pumps, four valves, and two magnets that are energized or de-energized by relays which operate according to voltage levels sent from the Raspberry Pi. A python coded GUI displayed on a touchscreen allows user input of mode run times and the number of cycles the process should repeat while also displaying continuously updated system information.In addition to automated control, the user has the option of manually controlling the system by way of physical switches on an external panel with LEDs that serve as a visual indicator of system status. The final system designed was considered a success as a data log was produced containing the systems operation along with correct temperature and pH data that match the expected and observed system operation through an automated cycle and a manually controlled cycle.
Haines, Thad and Joyce, Frank, "Raspberry Pi Human Machine Interface and Control System for an Electromagnet Water Filter" (2017). Proceedings of the Annual Montana Tech Electrical and General Engineering Symposium. 19.