Design And Implemention Of BACnet/ZigBee Interconnection Network Based On Embedded System

BACnet protocol defines an open structure of the building automation system, is the only standard of building automation communication protocol, which widely used in building automation field with the characteristics of openness, practicality and easy to integrate with other network. However, BACnet is a wired communication network, its shortage of high cost, poor flexibility hinders the upgrade and expansion of building automation system. This paper analyses and studies the BACnet communication network and wireless communication network technology, to determine the design and implementation of BACnet/ZigBee interconnection network based on embedded system, to solve the problem of BACnet cable network problems.This paper analyzes the three extension mechanisms of BACnet network, and determines to extend BACnet network from the protocol architecture which adds ZigBee application system to the BACnet architecture, namely expansion of data link layer and physical layer. The virtual data link layer is introduced into BACnet network and ZigBee network for providing a protocol interface of communication between heterogeneous network.This paper deeply studies the state mechanism in MS/TP network, and puts forward a kind of error retransmission mechanism combined with the CRC, which adds conversion of retransmission state in the state machine, to ensure the send and receive of data frame. Presents a dynamic bandwith allocation algorithm to improve the real-time of network, by Simulink and Stateflow Fusion Modeling to emulate on the performance of dynamic bandwidth allocation algorithm, the results show the proposed algorithm can effectively improve the utilization of network bandwidth, and improve the quality of communication.This paper designs the system scheme according to the research target, regards micro controller STM32F107 as the main processor of interconnection network system to realize the control and data processing for the system; EIA-485 driver using MAX485 chip, be responsible for data transceiver task on fieldbus; RS-232 driver using MAX232 chip, achieves the target of communication between controller and PC. verify the experimental feasibility of interconnected system by three aspects, and the verification results to get the expected results.This paper accomplishes the system design, and provides the complete test results.