Abstract : This paper introduces a real-time water level monitoring experimental system based on PLC and AC frequency converter designed and developed in our laboratory. The hardware composition, software design, and network communication implementation of the system are presented. Keywords : Monitoring; Configuration software; PLC; AC frequency converter; Communication 1 Introduction Water level regulation experimental devices are commonly used experimental systems in the teaching of automatic control systems. Traditional experimental methods use unit automation instruments or microcomputer experimental devices. However, with the development of computer technology and control technology, the original experimental devices can no longer adapt to the development of modern industrial control technology. In order to enable students to not only intuitively and vividly learn the characteristics, parameter adjustment methods, and debugging processes of system objects in automatic control system experiments, but also to have as much contact as possible with modern industrial control technologies, such as PLC technology, frequency converter control technology, network communication technology, CRT technology, and intelligent control technology, we have researched and developed a real-time monitoring experimental device based on PLC and AC frequency converter. This system integrates data acquisition, microcomputer control, PLC control, and frequency converter control, providing excellent experimental conditions for teachers and students. The following experiments can be conducted using this experimental system: 1. 1. PLC structure, principle, usage, and communication; 2. Structure, principle, and usage of AC motors and AC frequency converters; 3. Use of industrial control configuration software tools (KingSCADA, etc.); 4. Communication network structure and application; 5. Composition and application of microcomputer distributed monitoring systems; 6. Adjustment of dual-capacity water level objects. 2. System Introduction This system is a water level real-time detection and control experimental system. We adopt a generalized hierarchical monitoring system structure, dividing the entire system into three levels: PLC control level, upper computer monitoring level, and management monitoring level, as shown in Figure 1. [b][align=center]For details, please click: A Real-Time Monitoring System Based on PLC and AC Frequency Converter[/align][/b]