Abstract : This paper introduces a small distributed computer system composed of a frequency converter supporting the Modbus protocol and an industrial control microcomputer (IPC). In the IPC programming, Visual C++ was used as the basic development tool, combined with ActiveX technology, and the database was accessed and manipulated through ODBC data sources, successfully realizing real-time monitoring and information management functions. Keywords : Frequency converter, real-time monitoring, database 1 Introduction Due to the important role of frequency converters in energy saving and automatic control, they have been widely used in industrial and mining enterprises. Frequency converters are generally installed with field equipment, which are often located in dispersed locations, harsh environments, and far from the control room, posing certain difficulties for operators in operation, inspection, and meter reading. With the improvement of automation and informatization, staff hope to be able to monitor and manage information in real time without leaving their offices. This system, tailored to the specific needs of a company's equipment, automatically regulates the cooling water temperature using 16 fans. Each frequency converter adjusts and controls four fans (one operating at variable frequency, the other three operating/stopping at industrial frequency as needed). Besides automatic detection, control, and power output functions, the frequency converter also supports the Modbus protocol, providing favorable conditions for remote microcomputer monitoring. The system achieves real-time monitoring of parameters such as voltage, current, power, and frequency of the frequency converters and fans; control operations such as fan start/stop and operating mode settings; and generates various operating parameter curves and historical fan data statistical reports, thereby saving significant manpower and improving work efficiency. 2. System Composition and Functions This system uses an industrial control microcomputer (IPC) in the control room as the host computer, connected to each frequency converter (as a slave computer) in the field via a 232/485 converter and shielded twisted-pair cable, forming a small distributed computer system. No other hardware equipment is required. The system composition diagram is shown in Figure 1. The functions implemented on the IPC include: display of electrical wiring diagrams and corresponding equipment operating parameters, fault and over-limit alarms, control and equipment operating parameter setting operations, and information management. Specifically, the electrical wiring diagrams and corresponding equipment operating parameters are displayed on the screen, including: voltage, current, power, frequency, and temperature; equipment status (running, stopped); fault alarms; and equipment operating parameter over-limit information. The control and equipment operating parameter setting operations involve remote control operation of the frequency converter, including: starting and stopping the frequency converter and fan, and setting control (PID regulation) parameters. Information management periodically archives the detected operating parameters, analyzes and processes them, and generates: voltage, current, power, frequency, and temperature curves, bar graphs, and charts; comprehensive operating parameter reports; and operating parameter over-limit alarm and fault alarm record tables. A schematic diagram of the system functions is shown in Figure 2. [b][align=center]For more details, please click: Design of Real-time Monitoring and Information Management System for Variable Frequency Drives[/align][/b]