Research Of Dual-Communication-Mode Environmental Monitoring And Control System Based On ZigBee/RS-485

Warehouse management has high requirement for the indoor environment,especially for some special warehouse like archives,which are very sensitive to varieties of environmental parameters such as temperature and humidity because of the particularity of the content preserved.So it is necessary to provide a stable and suitable preservation environment.In the past,it is often necessary to manually check the environmental parameters of a warehouse,which is expensive and obviously not sustainable.Later,various kinds of warehouse environment monitoring system based on different networking technologies are gradually appearing on the market.The wireless networking technology has become the first choice for the construction of the network because of its flexible networking and no wiring.And the wired networking technology has the advantages of low difficulty of development,high stability and cost performance,also suitable for lots of scenes.Under this background,this paper proposes a kind of environment monitoring and control system providing wireless and cable two communication modes at the same time,which can be selected by the administrator according to the working environment.First of all,this paper investigates the development status and shortcomings of warehouse environmental monitoring,then formulates the project plan according to the needs of warehouse environmental monitoring.Secondly,the networking technologies has been investigated.ZigBee technology is selected as the wireless communication mode,and RS-485 bus is used as the wired communication mode.This paper mainly studies and researches the ZigBee technology,collates and summarizes the technical details.Based on ZigBee technology and RS-485 bus,a communication scheme is drafted to achieve easy switching of two communication modes,wireless and cable.The software and hardware design of ZigBee communication module are completed based on CC2530 chip and the Z-Stack protocol stack launched by TI company.Then,the appropriate sensors are selected,such as temperature and humidity,CO,CO2,O3,dust,water immersion and smoke sensing.Based on STM32 chip,a system automatically monitoring temperature and humidity,concentration of dust and multiple kinds of gases,statement of water and fire in the warehouse is actualized.It also provides alarm function in the case of abnormal occurrence,and supports communication between controller and multiple monitors.Combining actual needs,the embedded real-time operating system ?C/OS-? and FreeModbus protocol stack are transplanted to ensure real-time,stability and scalability of the system.Meanwhile,communication software design of controller is completed.Finally,the system is built and debugged.After long time field test,the environmental monitoring and control system designed in this paper can realize all function and has stable performance,meeting the expected requirement.