Diseño e implementación de dos técnicas de control aplicadas a una planta de recirculación de líquidos en el Instituto Tecnológico Superior Sucre.

Abstract

This work presents the implementation and comparison of two control techniques for the flow variable, in the liquid recirculation module belonging to the Instituto Tecnológico Superior Sucre; the modeling of the plant was carried out in the first instance using the system identification method, applying the Matlab programming tool; and then the PID and Predictive control systems were implemented in the Simulink software. The code obtained was used to create the blocks in a programmable logic controller (PLC) Siemens S7-1200. To have the parameters with which to compare the performance of the above mentioned controllers, a PID control is implemented, but using the block integrated in the TIA PORTAL software; and the dynamic functioning of the process is observed, for the different controllers. The results obtained from the experiments show that the Predictive control system has a better performance in the dynamic state, compared to the PID controllers designed in Matlab and native to the programmable automaton. In addition, a human-machine interface was designed and implemented to allow interaction with the process. The interface represents an indispensable tool for the study of control systems by people who use the module within the educational institution. It was possible to implement other control systems in the programmable controller using the ST programming language (structured text) and the PLC CODE tool of the Matlab software. Finally, to improve the signal of the measured variable, a 4 to 20 mA industrial-type flow transmitter could be incorporated to obtain a distortion-free signal.