| The rapid development of information and microelectronics technology continues to drive the automatic control technologies reforming and innovating in the manufacturing industry field.An opend and networked automatic control architecture is gradually formed,while the fieldbus technology is playing an increasingly central role and its applications are becoming more widespread.However,there are more than60 kinds of global fieldbuses at present,and each has its own advantages and disadvantages.The incompatibility between different field buses brings great inconvenience to users.Therefore,the integration of protocols between different bus standards has gradually become a research hotspot.Based on this situation,this paper selects the Modbus fieldbus and Profibus-DP fieldbus that are widely used domestically as research objects,and designs a protocol conversion module between Modbus and Profibus based on STM32.This article studied the Modbus/Profibus protocol conversion process based on C language using M3 kernel.The paper selects the VPC3+C chip which integrated with complete DP protocol from VIPA of Germany as the underlying protocol processing chip.Its excellent performance and simpler pin interface are easier to embed into the control system.In the process of external data exchange,the paper selects different interface drivers according to the requirements of Modbus and Profibus technology.In term of the highest 12 Mbps Profibus-DP requirements,the ADM2486 was selected for the RS-485 driver chip,and its data processing rate can reach 20 Mbps.As the Modbus fieldbus transmission rate is relatively low,the article selected the RSM3485 S chip with magnetic coupling isolation protection to meet the communication requirements.The article successfully implemented bidirectional conversion of Modbus protocol and Profibus-DP protocol with STM32 microcontroller and other related protocol chips.On the Profibus-DP fieldbus,the protocol conversion module acts as a slave to communicate with the PLC master.On the Modbus fieldbus,the protocol conversion module acts as the master to send commands to the Modbus slave device and receive the slave data.Through the protocol conversion module developed in this article,users can quickly configure the Modbus slave device to the Profibus-DP fieldbus network,which helps to enhance the Modbus networking capability,shorten system develop time,reduce the cost of system design maintenance and makes the system design more flexible. |
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