Design and implementation of digital monitoring system for urban interconnected fire safety

0 Introduction

As an integral part of the modern urban safety system, fire protection has become increasingly important with the rapid development of modern cities. However, most of the urban building fire safety systems on the market are single and simple alarm devices, which are not conducive to receiving and handling alarms, seriously restricting the safety protection of buildings and delaying the combat and rescue time of the fire brigade. Through investigation and statistics on the causes of various fire accidents, it is found that most fires are caused by human factors, such as missed reporting, late reporting of fire information, and failure to open alarm equipment in time. For this reason, it is of great significance to establish a digital system for urban building fire safety and connect the fire protection system of each building into a network. Networked monitoring and management is also an inevitable trend in the development of fire protection. At present, urban fire protection work is mainly based on units and is an independent system. This model is more suitable for smaller cities. However, with the expansion of urban scale, this decentralized system shows its limitations. First, decentralized systems are not easy to manage centrally. As managers of urban fire protection, they must go deep into each unit to investigate the fire protection work on the spot, which is inevitable to leak and lose control. Second, information cannot be fed back in time. Information on the on-site situation and rectification of the inspected units cannot be obtained in time. Third, as a grassroots fire-fighting unit, due to uneven levels and different levels of attention, it may not be able to discover the disaster in time when it occurs, causing the fire to spread.

The reality requires that modern urban fire protection must form an omnipresent safety precaution network, which monitors every corner of the city at all times, can keep abreast of the local situation, and report to the monitor in a striking manner when a major abnormal situation occurs. At the same time, it is also a database of urban fire protection conditions, which can query the information of the subordinate areas at any time and store them for record. The development of modern science and technology provides sufficient technical guarantee for this requirement. With the rapid development of Internet technology, the Internet is becoming more and more closely connected with people's lives. The Internet not only provides people with a vast amount of network information resources and becomes a window for people to understand the world, but also combines the Internet with the existing working mode, giving full play to the advantages of the Internet's speed and information sharing, which will play an important role in improving the existing work efficiency and enhancing the management of functional departments.

1 System composition

The construction of the urban Internet fire monitoring system is a systematic project. Since it involves various units in the city, fire management departments and Internet technology providers, it is a complex project. However, once it is in operation, the social benefits it brings are undoubtedly huge. Figure 1 is a schematic diagram of the urban fire network monitoring system.

As the cornerstone of the interconnected fire monitoring system, the scattered fire monitoring rooms of various units are both providers and beneficiaries of fire information. Each unit is responsible for the collection of fire information of the unit, the maintenance of the alarm system and the handling of specific conditions. This part is the most basic and the most important. If this part of the alarm system is paralyzed, there will be no information collection, not to mention the monitoring of the monitor. Only when the alarm system of the unit is in real-time monitoring and early fire hazards are discovered in time, on the one hand, the unit duty officer can be notified in time, and on the other hand, even if the unit duty officer is negligent, it can be reported to the city monitor, and the city monitoring center will deal with it in time to avoid a catastrophe. This has an important practical role in real life. It can be said that this double urban fire insurance can prevent many fire hazards. The urban fire monitoring center is generally located in the fire brigade. As the last insurance before the fire, its role is also very important. Because in real life, due to various reasons, not every unit can fully implement the duty system. In this state, a corner of the city is in danger of being out of control. Once there is a dangerous situation, disaster is often inevitable. If a city fire digital monitoring network is established, when the on-duty personnel find an abnormal situation somewhere, they will first notify the local on-duty personnel, and when there are signs of escalating disasters, they can immediately notify the fire department to rush to the scene. In normal times, this is also where the city's fire data is located. The historical status of each department, key department information, and unit information can be queried in a timely manner when needed. The Internet network that serves as a bridge between units and the city fire monitoring center is generally provided by the local telecommunications department. With the popularization of modern networks and continuous technological upgrades such as broadband networks, optical fibers, and integrated information networks, information access will become easier and easier.

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The fire monitoring room of each unit is the key to the system and the center of the system. It is mainly composed of intelligent fire detectors, control modules and fire alarm controllers distributed at the detection and control site. Intelligent fire detectors detect the smoke concentration and temperature of the on-site environment, convert them into electrical signals, perform corresponding processing, and then transmit the data to the fire alarm controller; the fire alarm controller receives the data and processes and judges it to determine whether a fire exists. If the result of the processing is a fire alarm state, an alarm signal is issued and the corresponding control module is started, such as starting a fire pump, fan, etc. The more popular intelligent fire automatic alarm control systems on the market are mainly produced by Qinhuangdao Bay Company and Keda Innovation Company.

The city interconnected fire safety digital monitoring system adopts non-polar bus transmission, micro-power design, dedicated flexible address encoding and decoding addressing and other advanced technologies, advanced system networking methods and communication protocols. Through the network router networking capacity can reach any node, and can connect systems from different manufacturers into a network. It can complete the compensation for changes in external environmental parameters and store the characteristic curves of environmental parameter changes, which greatly improves the real-time and accuracy of the entire system in detecting fires. As an upgraded product on the market, the city interconnected fire safety digital monitoring system can well complete the existing system transformation and the design and installation of new buildings. It has a broad market application prospect and is more competitive in the market than the current various fire alarm control systems.

At the same time, the controller network interface module is also the key part of connecting the fire alarm controller and the network. At present, most fire alarm controllers produced by fire protection enterprises generally provide RS 232 interface or RS 485 interface, and some provide CAN bus interface. In general, RS 232, RS 485 and CAN bus interfaces represent the vast majority of data interfaces provided by fire alarm controllers to the outside world. The urban interconnected fire safety digital monitoring system adopts a centralized intelligent system structure or a distributed intelligent system structure. The network communication system structure can be formed on the basis of these two systems. The special feature is that computer data communication technology is applied to fire alarm controllers, so that controllers can exchange data information through Ethernet, TokenRing, Token Bus and other communication protocols, as well as dedicated communication lines or buses (RS 232, RS 422, RS 485), to realize the functions of fire monitoring system hierarchical function setting, remote data call management and network communication services. In this way, combined with the distributed intelligent data processing method, it can adapt to the development needs of high-performance fire monitoring systems, lay the foundation for the construction of urban fire data information network systems and meet future development needs, and realize data communication and interoperability between different fire alarm systems through TCP/IP, a mainstream Internet protocol plus software interface. This is a relatively perfect solution. For this purpose, a universal intelligent interface converter is designed, which uses RS 232, RS 485 and CAN bus interfaces as one port, and TCP/IP and Modem interfaces as another port to realize the interface conversion function from terminal data to network (as shown in Figure 2).

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2 Software Design

The above is just a rough overview of the architecture and hardware environment of the city interconnected fire safety digital monitoring system. The software environment is equally important for completing such a network system. Such a system will adopt the popular client-server system. The unit end, as the server, is the provider of information, and the monitor, as the client, is the collector of information. The monitor can send a request information command to the server at regular intervals. After receiving the command, the server will reflect the unit's information to the monitor according to the level status. For example, when only one detector alarms, a low-level forecast is sent to the client, and when there are multiple detectors alarming, a high-level forecast is sent. This can prevent a certain detector from making a false alarm and causing unnecessary actions. At the same time, as a city fire monitoring center, it can also focus on monitoring key departments according to the level of the forecast. For example, when a unit has multiple detectors that sound an alarm, the number of inspections for that location can be increased.

FIG. 3 is a schematic diagram of the framework structure of the server and client programs.

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The inspection module on the server side is generally connected to the alarm controller through the RS 232 port of the computer. The alarm controller is specifically responsible for the detection of all detectors in the unit. Once an abnormal situation occurs, the display module will indicate its specific location on the computer screen and record it in the local database.

The linkage module can be set to automatic or manual. In automatic mode, when the abnormal situation meets the pre-set conditions, the response equipment such as alarm bells, sprinkler pumps, etc. can be automatically started after a delay.

The data query module can query the original alarm records and the operating status of existing equipment to have a clear idea of ​​the situation.

The communication module is responsible for communicating with the city fire monitoring center. When the city fire monitoring center sends a query command, the local situation can be reported to the monitor. At the same time, once an abnormal situation occurs, it can also be automatically reported to the monitor according to the level to avoid missing situations when no one is on duty.

The client's communication module can automatically send inspection commands to various units to understand local conditions. Considering the large coverage area and long inspection cycle, it should also be able to quickly respond to information actively sent by the server.

The city graphic display module can display the floor plan of the entire city, and can roam, zoom in, automatically locate, etc. When an abnormal situation occurs, it can automatically find the location of the accident, automatically locate and zoom in, and display it to the monitor in a striking way. At the same time, the corresponding unit information is searched in the database and provided to the monitor to facilitate the monitor to take action.

The database operation module is responsible for the information storage, query, update and other operations of each unit. Because its scale is generally large, and the corresponding information should be quickly found when abnormal situations occur, relatively large databases such as SQL Server, Oracle, Power Builder, etc. are generally used. As the database on the server is generally small in scale, you can consider using file storage or Foxpro, Mysol, Accsess, etc.

The software of the intelligent fire alarm controller is mainly composed of the main program, serial interrupt service program, timer interrupt service program, etc. The keyboard information is read in a query mode. When there is keyboard input, it is transferred to the corresponding subroutine for processing. The timer interrupt service program mainly completes the display and update of the detection data. The serial port interrupt service program is mainly used for communication with the display on the same floor. In the software design, when it is necessary to judge the on-site conditions detected by the detector, filtering algorithms such as taking the arithmetic mean are also adopted to filter abnormal signals such as interference.

The author has implemented the above-mentioned urban interconnected fire safety digital monitoring system in a small-scale local area network and achieved satisfactory results. The program architecture adopts client/server. Both the client and server are implemented with Visual c++ 7.0. The communication between the client and the server adopts TCP/IP protocol, and sockets are used to send and receive data. The database server uses Access, the client uses SQL Server 8.0, the client operating system is Windows NT, and the server operating system is Windows XP.

3 Conclusion

Urban fire protection is an old yet young cause. With the development of the times, it is constantly endowed with new vitality and content. Combining the Internet with fire protection technology has important practical and economic significance for reducing urban fire hazards and improving urban fire safety levels. However, in order to fundamentally solve the backwardness of my country's fire protection system, while strengthening urban construction management and increasing investment in modern fire protection equipment, it is more important to use the "urban interconnected fire safety digital monitoring system" with high technological content and fast response speed to enable it to monitor the operation of the entire city's fire automatic alarm equipment in real time, and to scientifically analyze the surrounding geographical environment, water sources, etc. when a fire occurs, so as to eliminate the hidden dangers of fire in the bud. The application of the "urban interconnected fire safety digital monitoring system" can strengthen the management of on-duty personnel of networked units, strengthen the management of in-service fire automatic alarm equipment, and promote the continuous updating and development of equipment manufacturers' technology.