Abstract : This paper applies Siemens' PROIBUS DP to realize communication between a PLC and multiple frequency converters, accurately controlling the frequency converters, and provides the relevant program. Keywords : Frequency converter, PLC, PROFIBUS 1 Introduction In recent years, with the rapid development of AC frequency converter technology, it has been widely used to control the speed and position of AC motors. Fieldbus technology has developed rapidly along with computer technology, network communication technology, and microelectronics technology, driving the entire automation control to a higher level. Fieldbus technology realizes data transmission and information exchange between control devices according to open communication protocols, forming various automated control systems that conform to the production site. It is currently one of the hot topics and development directions of automation control technology and is known as the computer local area network of the automation field. This paper adopts the PROFIBUS-DP fieldbus, which is one of the internationally used fieldbus standards. With its unique technical characteristics, strict certification specifications, open standards, support from many manufacturers, and continuously evolving application rules, any device that conforms to the PROFIBUS-DP protocol can be connected to the bus, making it the most important fieldbus standard. The transmission rate can reach up to 12 Mbit/s, the maximum distance is 100M at 12 Mbit/s, and the maximum distance is 200M at 1.5 Mbit/s. The transmission distance can be increased by using repeaters. The maximum transmission distance of the network can reach 90 km. Up to 126 slave stations can be connected. It is suitable for various communication media. 2 Control content and control requirements This article takes the high-speed coin pressing machine as the control object. In order to meet the requirements of large-scale production, the speed of the high-speed pressing machine must reach at least 700 coins/minute, and the quality of the product must be guaranteed. The main process is: the feeding mechanism sends the coin to the coin-pulling mechanism, the coin-pulling mechanism accurately pulls the coin to the main drive mechanism, and the pressing is carried out in the main drive to process it into finished products. Its main features are: (1) high speed: only 85ms is needed to complete one coin; (2) the transmission between each mechanism must be well coordinated. In particular, it is emphasized that the main drive and the coin-pulling mechanism must be very accurately coordinated. The coin-pulling time is only about 20ms. Therefore, the dicing machine drive uses the SIEMENS MC servo CNC system. The MC servo CNC system is SIEMENS' latest high-speed motion control system and is a shaftless drive system (a shaftless drive system obtains the synchronization signal from the main drive; that is, a high-resolution photoelectric encoder is installed on the main drive crankshaft. When the main unit is running, the encoder's pulse signal is sent to the dicing machine servo controller for control. The servo controller accurately controls the dicing machine's movement, thereby achieving the requirement of synchronous operation with the dicing machine). [b][align=center]For more details, please click: Multi-Voltage Inverter Control System Based on PROFIBUS Bus[/align][/b]