Research And Design Of Real-time Conversion System For Multi-fieldbus Protocol

With the proposal of "China Manufacturing 2025" plan,industrial control network has become a research hotspot.As the main part of industrial control network,fieldbus greatly improves the efficiency of data transmission.However,due to the commercial competition of major manufacturers,there has not yet been a unified fieldbus international standard.At the same time,the application of Ethernet to industrial control network is also an irresistible trend.Therefore,it is unavoidable to form heterogeneous networks in the industrial field.It is particularly important to achieve efficient,accurate and real-time communication between heterogeneous networks.In addition,most of the fieldbus controllers produced abroad are used in our country at present.Independent research and development of controller chips is of great significance to gradually get rid of foreign products and promote the industrial development of our country.Under the premise of in-depth study of relevant research results at home and abroad,this paper proposes a design scheme of real-time conversion system for Multi-Fieldbus protocols for the conversion of different protocols.The design scheme makes full use of the advantages of IP soft core and FPGA.Fieldbus controller,Ethernet controller and protocol conversion module are implemented on an FPGA chip in the form of IP soft core.The main research contents and innovations include:(1)The design scheme of real-time conversion system of Multi-Fieldbus protocol based on FPGA is proposed.The system is designed to realize the protocol conversion between CAN bus and Modbus RTU bus and Ethernet,and the usage scenario and functions of the system are introduced.The proposed design scheme includes software design scheme and hardware design scheme.(2)Based on the in-depth study of CAN protocol,the design scheme of CAN controller based on FPGA is proposed and implemented.Firstly,the design ideas and principles of each module are elaborated in detail,and then the functions of each module are realized one by one by using hardware description language Verilog HDL.Finally,the modules are integrated and the functions of the designed CAN controller are verified by RTL simulation.(3)A design scheme of Modbus RTU bus based on FPGA is proposed and implemented.Then we use Verilog HDL language to realize the function of the module in the scheme.Finally,the modules are implemented and integrated,and the expected function of the designed Modbus RTU controller is verified by RTL simulation.That is,the master and slave stations can send and receive information frames normally,and the master station can send the correct request frames according to the requirements,and the slave station can achieve the correct response to the information frames.(4)The implementation scheme of UDP/IP Ethernet controller based on FPGA is proposed.Then the protocol conversion frame is designed to realize the protocol identification and conversion of the protocol conversion module.Finally,the software parts of the protocol real-time conversion system are integrated,and RTL simulation is carried out to verify the function and real-time of the designed system.(5)The design scheme of hardware platform for real-time conversion system of Multi-Fieldbus protocol is proposed and realized.Firstly,each circuit module in the scheme is designed.Then an experimental scheme based on hardware platform is designed to verify the function and real-time performance of the designed system.Finally,the average delay and delay jitter of the protocol conversion system under various conditions are obtained by analyzing the experimental data.Through the delay analysis,the designed system has good real-time performance and can meet the needs of industrial field.