Abstract: This paper studies an experimental setup for a process control system based on a two-level network of PROFIBUS fieldbus and Ethernet, with the controlled object being a simulated electric boiler. The application of the fuzzy PID control algorithm in the boiler level control experimental system is highlighted, and the experimental principle and the design and development process of the experimental teaching application software are explained. Experimental results show that under fuzzy-PID control, the dynamic and static performance of the system is superior to that of the traditional PID controller.
Keywords: Fuzzy PID control, robustness, micro electric boiler, process control network
Abstract: A process control system based on two-level networks—Profibus and Ethernet for experimental equipment is studied in this paper. The controlled object is a process imitating the electrothermal boiler. The application of fuzzy-PID control to the boiler's level control experiment is emphasized by exhibiting the experiment principle, the design and development process of the experimental teaching application software. The field test shows that with Fuzzy-PID control the system's dynamic and stationary performances are better than with classical PID control.
KEY WORDS： Fuzzy-PID control; Robustness; Micro-size electrothermal boiler; Process control network
1. Introduction
An electric boiler is a device that converts electrical energy into heat energy to produce steam or hot water [1]. It can meet the needs of high-rise buildings, commerce, small industrial and mining enterprises, automobile and shipbuilding industries. Compared with other fuel boilers, the main features of electric boilers are: high thermal efficiency; small size, compact structure, no need for fuel and combustion waste storage space; fully automatic control without human intervention; rapid and flexible control, simple and convenient operation, and good load regulation performance; simple and convenient maintenance; good safety performance and long service life. At present, electric boilers have been widely used in industrial process production in my country.
Based on the characteristics of electric boilers, we developed a miniature electric boiler control system experimental device. This device is a miniature boiler heating and water supply system that simulates an actual electric boiler used in industrial settings, offering realism and intuitiveness. The control system uses an S7 series PLC at its core, connected to the I/O process station via a PROFIBUS fieldbus. At the upper level, four PCs serve as engineer and operator stations, connected to the PLC via Ethernet for student experimentation. This control system provides various types of input and output signals, facilitating the simulation of different operating states in the production process. The system structure and control methods are diverse and representative. This paper uses boiler liquid level control as an example to study the control of an actual production process.
For details, please click: Fuzzy PID Control of Liquid Level in Miniature Boilers
