Design And Implementation Of Iot Gateway For Smart Building Devices

The Internet of things,as another wave of information technology after the Internet,has entered into people's lives.It can realize information exchange between objects and objects,and has very important application value in the field of intelligent buildings.However,there are many kinds of network in the existing building,and even the special protocol of the manufacturer,which leads to the failure of the building subsystems to communicate with each other,resulting in the waste of a large number of effective resources.Therefore,for the existing buildings and new buildings of the Internet of things energy system,we need to use the Internet of things gateway for unified management.As the protocol standard for the future of the Internet of things,MQTT relieves the coupling of applications with its minimal bandwidth and publish/subscribe message mode,and can effectively integrate the current electrical equipment network.In this thesis,two communication protocols between ZigBee and ModBus are forwarded through MQTT message agent to realize protocol transformation.First,the purpose and significance of the research on the Internet of things gateway is clarified.On the basis of the analysis of domestic and foreign research status,the access layer ZigBee and ModBus protocol and the processing layer MQTT protocol are introduced in detail,and the design of the application of MQTT to the intelligent building field is proposed.Secondly,a clear analysis is made to the design objectives and overall architecture of the IOT gateway to the intelligent building,and the hardware and software environment required for the Internet gateway are designed respectively.From the three levels of access layer,processing layer and application layer,the protocol conversion function of Internet of things gateway is realized.ZigBee adopts tree topology self organizing network to realize data acquisition of terminal sensor data.ModBus uses master slave communication mode to realize data exchange.In order to achieve the conversion between MQTT and ZigBee and ModBus protocol messages,a custom frame format is designed.The workflow of the gateway is designed in detail,and the custom frame parsing process is given,and the push of the message is realized through the Mosquitto proxy software.The Web server architecture of B/S mode is used to realize the access to field data in different places.Finally,the integrated test of the Internet of things gateway is carried out.It mainly tests and analyzes the gateway protocol conversion function and data.query function of the Internet of things.