Proportional digital controller using “ARDUINO UNO” for liquid level control of a tank

The design of a digital controller for the liquid level control of a tank was started by obtaining the transfer function of the plant: liquid level system. The structure of a digital control system was taken into account by selecting the appropriate sensor, actuator and power circuit for the plant. Continuing with a brief review of digital control theory, the discretization methods of the transfer function and the design of digital controllers using the root-place method were studied. Data were acquired to characterize the plant using MATLAB; then compared to the transfer function, initially found for final adjustment, the MATLAB rltool function was used for the digital design. Simulation in blocks was carried out in SIMULINK, configuring the real physical limitations of the system. The code of the digital controller designed in the integrated development environment of the Arduino electronic development board was implemented, finding the Z transform inverse previously. The data was stored in MATLAB and the simulation results were compared showing consistency. It was observed that a proportional control design is sufficient for this type of first order systems that have their pole at the origin. Ultrasound sensors are accurate in measuring water level height unlike infrared sensors.