1 Introduction
Road lighting is an important part of urban public facilities. At present, most of the domestic road lighting systems do not use networked monitoring and management. Only simple lighting and switching control of lighting equipment can be carried out on a regional basis. The switch control of most urban street lights is still Decentralized control by traditional transformers (distribution boxes), can not effectively monitor street lights, lack of flexible operating system, so there are a series of problems: such as complex systems, difficult to manage; street lights cover a wide range, difficult maintenance; switch The control efficiency is low, and the power is wasted seriously. In view of the current lack of street lighting control and management level in the city, the author designed a street lamp wireless monitoring system, which can realize intelligent control of urban street lights and save energy. The system is mainly divided into three layers, which are a street lamp management center with a human-computer interaction interface function, a street lamp node information for transmitting a street lamp, a street lamp monitoring sub-station for transmitting a street lamp control command, and a street lamp control terminal for collecting street lamp node information. The combination of GPRS communication and ZigBee wireless communication replaces the traditional wired transmission. Among them, the communication between the street lamp management center and the street lamp monitoring substation adopts GPRS technology, has the characteristics of wide coverage and high transmission rate, and can realize remote remote operation; between the street lamp monitoring substation and the street lamp control terminal and the street lamp control terminal The communication uses ZigBee technology.
2. System structure of street lamp monitoring network
This design adopts the combination of GPRS technology and ZigBee technology, combining the advantages of both, which not only saves cost but also reduces the complexity of the system. The system adopts the three-layer mode structure of “Street Light Management Center—one street light monitoring sub-station one street light control terminal†to realize remote control operation of street lamps. Among them, the communication between the street lamp management center and the street lamp monitoring substation adopts GPRS technology, and the communication between the street lamp monitoring substation and the street lamp control terminal and the street lamp control terminal adopts ZigBee technology. The system operation targets thousands of street lights on urban roads. Through the management system, it is responsible for monitoring the various operating conditions of the street lights, such as monitoring whether the current voltage, current, power and other indicators of the street lamp nodes meet the specifications, and can realize the street light switch. Simple control. The structure of the entire street light monitoring system is shown in Figure 1.
Figure 1 system structure diagram
ZigBee network topology can be divided into three categories: network structure, star structure and tree structure. After analyzing the topology of ZigBee network, considering the wide coverage of streetlight monitoring, the natural environment is susceptible to weather, obstacles and electromagnetic radiation, and it is inevitable that terminal nodes will fail. Star networks and trees Shape networks are not suitable. Therefore, the system adopts a mesh ZigBee network, which has a large communication range and can realize the function of route discovery. When the network is faulty, it can automatically repair and achieve healing, thereby greatly improving the stability and reliability of the entire monitoring system. Sex, using the routing function to transfer. The network structure is shown in Figure 2.
Figure 2 ZIGBEE networking intention map
In a streetlight wireless monitoring system, there are multiple ZigBee networks, and a streetlight in the vicinity of a street forms a ZigBee network. Because the street lights are evenly distributed on both sides of the road, the distance between each two lights is generally 25~30m. Therefore, the system first needs to choose a suitable location to install the ZigBee network coordinator. In the ZigBee network, the ZigBee network coordinator is responsible for establishing the network. Generally, the ZigBee network coordinator is used to implement the function of the street lamp monitoring substation, which is responsible for maintenance. The operation status of the street lamp node on the street. After the routing node joins the network, the role of the controlling terminal in the streetlight monitoring system. In practical applications, in order to facilitate management, each streetlight control terminal can only join a ZigBee network to achieve single-lamp control. When all router nodes have successfully joined the network, the coordinator assigns a network address to the routing node according to the mesh network topology.
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