September 30, 2023
1. Program background
Due to rapid development of real estate industry in recent years, engineering tower cranes have become widespread in construction industry. Various types of accidents in operation of tower cranes often occurred due to violation of rules and overruns of tower cranes, as well as collisions of tower cranes, which led to huge loss of life and property damage. The concept of safe production is deeply rooted in people's hearts, and people's demands for safe production are getting higher and higher. The lessons and experience of many safety-related accidents show that process of using and behavior of tower crane must be effectively controlled in order to effectively control risk factors in operation of equipment, and to prevent and reduce number of industrial accidents related to safety of tower crane. How to ensure personal safety of builders and safety of property, such as building materials and equipment on construction site, has always been main concern of construction managers.
2.Technical requirements1.On-line monitoring and recording of information about work of construction site, timely and effective control over process of use and behavior of tower cranes. 2. Monitor and inspect active personnel at construction site, ensure high-definition image quality to distinguish between characteristics of suspicious personnel, to prevent outsiders from entering construction site to steal building materials. 3. The image must be clear. The high-definition camera on each tower crane must have a bandwidth of 3-4M, without delay, packet loss and compression loss. 4. The tower crane is a phased project, so wireless monitoring project is best to have reusable characteristics in order to save project costs.
Characteristics and problems of construction tower crane environment: 1. There may be interference in 2.4G frequency band around; 2. When construction tower crane uses a wireless bridge for direct communication. -point transmission or point-to-multipoint transmission, there may be obstacles in middle of individual points; 3. The tower crane is generally high, and it is easy to be attacked by lightning in thunderstorm weather. that equipment must be equipped with lightning protection in addition to level of external protection. 4. When installing wireless network bridges and surveillance cameras on tower cranes, power supply issues should be considered. The power supply system at construction site may be unstable, and there are many large equipment. The construction site should be equipped with voltage regulators to protect electronic equipment. 3. Circuit analysis1. The main control center and each tower crane use AR9344 5.8G network bridge to avoid signal interference. For wireless transmission, use point-to-point or point-to-multipoint mode. 2. Our wireless bridge has a transmission range of 5 kilometers and can carry 6 to 10 130W cameras. 3. Individual blockages and invisible dots can be solved using relay mode. However, it cannot be repeated multiple times, and bandwidth will decrease accordingly after relaying. 4. A lightning rod must be installed on top of tower crane, and lightning rod must be well grounded so that lightning does not hit ground in time. All of our network bridges are equipped with a lightning protection function so that equipment can work normally even in thunderstorms. 5. It is inconvenient to supply power to surveillance camera on tower crane. All series of network bridges have a POE power output function, which can supply power to surveillance camera through network cable, which saves trouble. complex power supply in project. 6. The network bridge device on tower crane is set to terminal mode, and monitoring center network bridge is set to AP transfer mode. center through network bridge device, so that construction site of tower crane can be understood in time state. In case of multi-point transmission of multiple devices, POE switches are used. We can also provide 8-port and 24-port gigabit POE switches (specific requirements can be selected according to actual technical needs)Fourth, advantages of solution 1 . Eliminate dead zones in security monitoring, use 5G network bridges to ensure transmission stability, monitor screen is clear and smooth, and will not drop packets all time;2. Remote synchronization Real-time monitoring, recording and displaying construction status around tower crane to ensure safety Production is adequately guaranteed;3. unified and centralizedmanagement and debugging can save a lot of time and labor;4. installation and commissioning of project is fast and flexible, and can quickly respond to needs, and equipment can be used after completion of project. Recyclable, saving design costs;
5. Installation Notes
When installing bridge equipment, there are two factors to consider: height and angle
1. Installation height
The basic principle of installation height of product is that there are no obstacles between two points within wrapping angle of product. If there is an obvious obstacle between two points, it is necessary to increase height of installation in order to achieve goal of stable infection transmission. As shown in figure below: installation height of network bridge should be H≥R+D
A typical reference value for minimum installation height R is as follows:
For example: if there is a distance of 1 km between two points and there is a building 5 m high, then optimal installation height of 2.4G wireless bridges at both ends is 5+5.5, which is approximately equal to 10.5 meters. Typically, wireless network bridge can be installed on roof of a building, or installation height can be increased with additional brackets, supports, etc.
2. Product installation angle
The antenna used by wireless bridge is a directional antenna, so during installation process, it is necessary to align antennas on both sides. The basic principle of installation angle is that with appropriate installation height of product, centers of two products are as close to each other as possible. The specific method is to roughly align directions of both ends, fix one end, and fine-tune other end to left or right until beacon signal level reaches its maximum value.
This solution is a brief introduction to wireless monitoring solution for outdoor tower crane projects. The wireless bridge series can be applied to other outdoor scenarios, including scenic parks, driving schools, public factories, warehouse schools, oil ports, forests. fire prevention, etc., a specific plan for security surveillance and outdoor coverage of wireless transmission should be formulated in conjunction with site environment.
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