Double Capacity Liquid Level Control System Based On Fuzzy PID Controller

Liquid level control system is on of the most important factors in the industrial production process. The quality of liquid level control is a factor that also impacts the continuous process system; therefore, in the study of industrial control system liquid level control is an important research direction. With the rapid development of technology, there is also a higher requirement for industrial automation; this in turn caused the traditional PID control to have difficulties to fully meet the process control requirements, hence giving birth to the development of advanced control theory in industrial control. In addition, the study of simulation techniques has peeked on the attention of researchers, thus greatly improving the speed of designing systems. Based on these designed the feedforward-cascade control system to effectively overcome the interference coming from various channels.This paper focuses on dual capacity water tank level control system as the research object. Through method of mechanisms and experiment constructs a mathematical model, and also studied simple single parameter and cascade control system. For the difficult tuning issues in control system the paper introduces fuzzy PID controller, through fuzzy controller tune the control parameters. This simplifies the process of tuning the parameters, especially when there are different control points in the system. Tuning using fuzzy PID controllers also has a good adaptability. Finally, this paper uses S7-300PLC as the underlying controller and a general purpose computer as the positioning machine, to achieve a feedforward-cascade control system based on PID controller. The experimental results show that, the system can better achieve the double capacity tank liquid level control system.