An Integrated Network Of Multi-protocol Conversion And Implementation

Fieldbus technique is widely applied in modern industrial control; it is widely used for its stong controllability, high reliability and excellent openness as a digital field communication network. However, many different proprietary field buses supporting different standards have been installed in industrial field in different time periods under different circumstances. In application, different buses often need to communicate with each other. Besides, users always need to operate and control many different field-bus devices. Thus it's necessary to address the interoperability issue and provide the uniform customer interface.To address the interoperability issue and facilitate the development of distributed control applications, the dissertation design and implement the Interconnect gate Unit (IU). IU is the core of system design target. Through analysis to the feature of different field-bus protocol, the dissertation researches its hardware environment and software design. IU adopts the SAMSUNG S3C2440 as the hardware core and embedded operation system VxWorks to implement field-bus driver and management of task scheduling, which improves real time ability and compatabilty.In aspect of fieldbus, the dissertation chooses CANbus, which is widely used in field environment, as bottom layer fieldbus. With both of CAN bus and RS232 bus, the composite network including field devices and monitor PC is implemented. Besides the feature of CAN bus and RS232 bus technique, the dissertation describes and imple -mentation of the protocol conversation with CAN bus and RS232 bus in detail. bus communication netwoxk experimental platformsystem. The dissertation analyzes the design of the whole system and describes the architecture and functional module division of IU, as so with the method and main points of function implementation.The dissertation chiefly focus on software design of IU. Firstly,a description of the software architecture and functional division is represented. Secondly, the interface of field-bus communication is implemented. The protocol conversation between CAN bus and RS232 bus is designed based on application-layer protocol design of CAN bus and RS232 bus. Furthermore, the dissertation starts with the connection between I/O subsystem and driver in VxWorks os, and analyzes the implemention course from I/O function to driver, the implementation of the CAN bus device driver and the analysis to task scheduling and communication between tasks based on VxWorks os is described in detail.The application environment is simulated in lab, the test to the reliability and exactitude of interface and performance is done. The results prove IU can performance correctly and implement the protocol conversation fuction between CAN and RS232 bus. That provides experience to protocol conversation in more complex environment.Finally, the research and work in the dissertation are summarized and further research target is discussed.