Abstract : The PROFIBUS-DP bus is increasingly widely used in modern tobacco processing production lines. How to correctly use I/O devices with DP ports is particularly important! This article describes in detail the application of Danfoss frequency converters based on the PROFIBUS-DP bus. Keywords : PROFIBUS-DP bus; Danfoss frequency converter; programmable controller 1 Overview PROFIBUS-DP is a robust, powerful, and open communication bus, mainly used for connecting with field devices and quickly and cyclically exchanging data. In addition, it has the following advantages: It conforms to modern control concepts—distributed control—thereby improving the real-time performance and reliability of the system; Through the PROFIBUS-DP bus, control components (with DP ports) from different manufacturers can be connected to form a compatible and complete control system, which also helps improve the system's flexibility and portability; Due to the use of the PROFIBUS-DP bus, tobacco factories can easily build information management networks as needed. Therefore, the PROFIBUS-DP bus is welcomed by designers and users. Danfoss frequency converters are widely used variable frequency speed control products manufactured by Danfoss. Due to their innovative VVCPLUS control principle, they can withstand extremely high load impacts across the entire speed range and respond quickly to parameter changes. They also boast advantages such as small size (book-style design) and simple operation. This article focuses on how to implement the control of a Danfoss frequency converter using the PROFIBUS-DP bus to achieve speed matching with upstream and downstream machines. This control method is typical in cigarette production lines and can be transplanted and reused without modification. 2 Hardware Circuit The following hardware circuit is a part of the PROFIBUS-DP bus of a cigarette factory's toner production line. The following example illustrates the application of Danfos frequency converters based on the PROBUS-DP bus: (1) When the system meets certain conditions: the PLC controls the start, stop, and running speed of the motor via the PROBUS-DP bus; (2) Through the PROBUS-DP bus, the frequency converter feeds back the running status information of the motor M to the PLC, such as motor running speed and motor torque. [b][align=center]For details, please click: Application of Danfoss frequency converters based on the PROBUS-DP bus[/align][/b]