Design of a PID Controller Based on Programmable Logic Controller (PLC) and Human Machine Interface (HMI) for Water Level Control: A Case Study in Soufflet Malt Ethiopia Using Siemens Simatic WinCC

Abstract

Water level control problem is a common process control problem in Soufflet Malt Ethiopia and most process control systems do not implement HMI based control system. This thesis focuses on the design and implementation of automatic water level control system based on a PLC, PID, and HMI. By using the existing PLC hardware, the water level control system is automated to minimize the need for human operators and the chance of human errors. This thesis has, three primary objectives: PLC and HMI system design, Auto-Tuning of PID controller and Simulation of the system using Factory I/O software. In PLC and HMI system design, hardware configuration of PLC, HMI configuration and visualization, Input and Output addressing, and the control algorithm is written. PID controller is configured and tuned using pre-defined auto tuning function of TIA portal. And finally, water level control system is simulated on Factory I/O software to check the functionality of the system. Automatic water level control system using PLC and HMI is designed to control the level of the tank and avoid wastage of water. The system automatically regulates the tank's water level based on the setpoint set on the HMI. And the system is visualized using a human machine interface (HMI). On the HMI level sensor feedback, pump animation, Fill and discharge valve opening percentage, alarms and trends are configured to have a better understanding of the process. Automating water level control system helps in reducing time consumption and human resource consumption, avoid water overflow, plant downtime because of low water level, increase production revenue by reducing downtimes caused by low water level or more safety and security for operators. It is noted from the simulation result that, the designed control system regulates the water level automatically without continuous human intervention as per the desired setpoint with minimum overshoot, faster settling time. In future by making some changes this project can be used in different industries related to fluids like petroleum industries or oil refineries for controlling the level of filling the tanks and avoid wastage. And with the latest PLC technologies and by maintaining secure connectivity and reliable data handling this system can be upgraded to cloud-based system for gaining remote connectivity to these on-site resources, accessing the data, and processing it.