Research And Implementation Of A CAN-Based Supervisory Control System Of The Gateway Station In Heating Network

CAN (Controller Area Network) is a real-time fieldbus network which today is very popular in industrial environments because of its very appealing characteristics and low implementation. This dissertation describes the hardware and software architecture of a CAN-based supervisory control system of the gateway station in heating network. In contrast to central control system (CCS), the CAN-based supervisory control system is high in reliability, flexible in configuration. The dissertation probes into the protocol and principle of CAN, and establishes the communication protocol in user layer. The dissertation presents a dynamic scheduling scheme to ensure that the key field messages can be transferred to the supervisory computer in time. A rule of three-way handshake is introduced to improve the reliability of the system. Frame filter is used to decrease the interrupt times in communication and improves the real-time performance of the system.Conventional supervisory control software have some disadvantages in that they are long in development cycle and bad in reusability. To overcome these problems, the author designs the configuration software platform for the CAN-based supervisory control system of the gateway station in heating network. The dissertation presents the configuration model based on the abstraction of the objects of the gateway station in heating network. Using this configuration software platform, the developers needn't program when they develop their projects. The only thing they need to do is to fill in some sheets to configure the software and the hardware of the application system. The dissertation puts forward the model of database configuration. The configuration software can build the real-time database and history database according to the configuration of the developers. The dissertation still brings forward the animation model for the configuration software, which can simulate the running status of the devices in the industrial environments.The system is flexible in the architecture of software and hardware. Although it is designed for the gateway station in heating network, it is easily extended to the other small and medium scale industrial applications.