Abstract : This paper introduces the general rules of fieldbus control in a frequency conversion speed-regulating drive system, and provides a general overview of the various performance parameters and bus structures of some commonly supported fieldbuses in frequency conversion speed-regulating systems. It also categorizes some commonly used frequency converters and servo systems according to the supported buses, and finally gives two examples of fieldbus control in a frequency conversion speed-regulating system. Keywords : Fieldbus; Frequency converter; ProfiBus; CANopen; DeviceNet; ModBus; ModBusPlus; SERCOS; Industrial Ethernet [b][align=center]A summary of the commonly adopted fieldbus control in a frequency conversion speed-regulating drive system SUN Jian-feng (Electrical Engineering College of Zhejiang University, Zhejiang Hangzhou 310027, China)[/align][/b] This paper demonstrates the bus structure and communication parameters of these familiar fieldbuses. It also cites two examples of fieldbus control systems. Keywords : fieldbus; frequency converter; ProfiBus; CANopen; eviceNet; ModBus; ModBusPlus; SERCOS; ethernet 0 Introduction Fieldbus control systems (FCS) integrate computer technology, information technology, and control technology. Since the 1980s, due to their advantages such as low cost, simple wiring, high reliability, and open protocols, they have gradually become the mainstream of industrial field control systems. In variable frequency speed control drive systems, products developed by some well-known global frequency converter manufacturers have increasingly higher levels of support for various fieldbuses. Therefore, by selecting different fieldbuses, different control requirements can be met, and system costs and maintenance expenses can be reduced. 1 Introduction to Fieldbus Control in Variable Frequency Speed ​​Control Systems Variable frequency speed control systems typically consist of several PLCs, frequency converters, sensors, human-machine interfaces (HMIs), and buses connecting these devices. Generally, some well-known frequency converter manufacturers have developed their own fieldbuses, such as the AFIO0 bus developed by ABB. However, practical applications often involve interconnecting equipment from many different manufacturers, which requires a more universal fieldbus. Most common frequency converters and PLCs support multiple fieldbuses, so simply purchasing appropriate adapters and communication boards (modules) allows for easy networking. Information on bus adapters can be found in the communication documentation of each frequency converter; it is not listed in this article. Table 1 categorizes commonly used frequency converter series according to their communication support. [b][align=center]For more details, please click: Overview of Commonly Used Fieldbuses in Variable Frequency Speed ​​Control Drive Systems[/align][/b]