Developing And Implementation Of Embedded Gateway Based On Heterogeneous Multi-protocol

In the field of industrial control network, process level control network and field control network have a variety of heterogeneous bus which has different characteristics of structure layer and communication protocol. At present, in the industrial control network, the commu-nication of control devices exist interoperability problems in heterogeneous protocol, which will affect the stable operation of control network. The basic ideas to solve this issue is setting the freezer bus control network as the research background and using the embedded gateway as communication controller of heterogeneous bus networks, so as to achieve the goal of effi-ciency and stability of information interaction between heterogeneous bus protocol devices.Through the analysis of heterogeneous protocol structure and characteristics of industrial control network equipment, this paper establishes a communication model for more hetero-geneous bus protocol gateway aiming at three communication protocol of PROFIBUS-DP protocol, MODBUS TCP protocol and MODBUS RTU protocol. According to composition characteristics of the model, data mapping and command buffer mechanism are proposed to run as the core of heterogeneous multi-bus protocol communication solutions. On the basis of this solution, the design of embedded gateway communication controller is mainly centered around ARM7 microprocessor, which sets process level devices as the main station of gate-way and field level devices as the slave station. The idea of data mapping management is preserving control parameters by the different field level equipment according to the provi-sions of the address space. The mechanism of command buffer is that time-sharing transmit communication data produced by process level equipment using queue mode. Sequentially, we solve the problem of the heterogeneous protocol device communication and concurrency operation. For the problem about different format of heterogeneous protocol packet data, we process the two bus communication message in separate time during the protocol conversion at the field level and process level. Based on actual design requirements, embedded gateway achieves communication of the three protocols of PROFIBUS-DP bus, Ethernet and RS485 bus. What's more, for the convenience of the process-level bus which is HMI device bus de-vices accessing to field-level the bus devices, we develop a MODBUS slave expansion inter-face. Heterogeneous bus protocol command message in the field bus communication timing conflicts can be solved effectively. Actual tests show that real-time and stability of embedded gateway can achieve with the design requirements during communication process of heterogeneous bus equipments. Hete-rogeneous bus protocol command message in the field bus communication timing conflicts can be solved effectively, the transmission efficiency and communication reliability of multi-protocol command message are greatly improved. At present, the gateway has been used in the refrigerator controller bus networks.