Research And Design Of Embedded Gateway Based On BACnet Protocol

BACnet is the unique open standard of ISO in the building automation and control network protocol. Building control equipment made by different manufacturers can communicate mutually and work coordinately to achieve interoperability as long as it corresponds with the BACnet protocol. But now, there is still some building automation equipment using specialized protocol for data communications. This dissertation mainly deals with the subject of how to use BACnet gateway to solve the problem of communication between BACnet device and non-BACnet device. The embedded gateway based on BACnet protocol provides a transmission channel and a device of data exchange for achieving information share between field control network and internet information network.Firstly, based on studying the architecture of BACnet protocol, the model structure of object and the standard of each protocol layer, coding and decoding of BACnet protocol is realized. It is the software base of embedded Gateway based on the BACnet protocol. Secondly, a design scheme of embedded gateway based on BACnet protocol is proposed and realized on the S3C44B0 development board, and a series of key technologies are analyzed, such as BACnet protocol stack, CGI technology, data synchronization between heterogeneous databases scheme. Embedded database is used in the internal part of the gateway, reducing the frequency of the Flash operation. Finally, data synchronization between SQLite database and MySql database is designed and realized, the data synchronization between embedded databases and background heterogeneous database is realized by socket program and log files. Data synchronization size is the record; the flow of data is determined by network communication conditions to avoid data losing, so the data synchronization delay can be decreased to the greatest extent.The results of the experiment indicate that proposed embedded gateway has many features such as stability, reliability, low cost and good transplant. It is valuable to achieve data synchronization system at the embedded gateway in industrial production and intelligent home areas.