Diseño e implementación de controladores programados en PLCs enfocados al control de procesos en entornos virtuales : diseño e implementación de un módulo didáctico virtual para control difuso de nivel de un tanque mediante el PLC modicon M580

Abstract

Factory I/O software offers a virtual industrial environment with programmable equipment through a programmable logic controller (PLC). This paper presents the development of a virtual training module with the objective of controlling the level of a tank, to which is added an application that includes the stages of filling, capping and labeling of bottles. During these stages, essential elements of the control are integrated, such as running control, general shutdown, emergency shutdown and management of possible failures. For level control, a fuzzy controller is designed considering two types of membership functions and a Takagi-Sugeno type fuzzy inference, thus creating a fuzzy PID controller. In addition, nonlinear gains are implemented to improve the response of the controller to disturbances, which is validated by comparing the performance of the fuzzy controller and its variations with a conventional PID. For this purpose, the control algorithms for both the conventional PID and the fuzzy PID are developed in the Modicon M580 PLC, which acts in a “hardware in the loop” structure, using the Control Expert Classic software. Finally, a Human Machine Interface (HMI) is programmed to visualize the behavior of the controllers and the current status of the process. This graphical interface includes a remote control that allows the process to be controlled from the HMI. Locally, the process is controlled from a virtual board made in Factory I/O and a physical board, where electromechanical control and supervision elements present in the Industrial Control laboratory are connected to the PLC. For the validation of the results, a comparative analysis of the performance of the controllers is carried out, evaluating them qualitatively through graphs and quantitatively through performance indexes.