Connection between cabling, alarm, and fire Communication Systems

In order to ensure the national property is not lost and the safety of people's lives, in accordance with China's national standards and regulations, important occasions and key parts in intelligent buildings or intelligent residential areas are required, fire Automatic alarm system, fire-fighting linkage control system, fire-fighting communication system, and other facilities must be set up.

The fire automatic alarm system and fire communication system are closely related to the Integrated Wiring System, but they have their own independent characteristics and requirements. Both parties must cooperate and coordinate with each other.

1. Overview of the automatic fire alarm system

The overview of the fire automatic alarm system described here is the most basic content. The automatic fire alarm system is an application system with multiple technical functions such as detection, alarm and fire suppression control. It involves multiple disciplines and specialties. Therefore, you must understand it, in particular, the components related to the Integrated Wiring System facilitate the design.

The automatic fire alarm system consists of fire detection alarms, fire alarm control devices, and control lines between them. Therefore, it is a large system that combines various components, devices, and devices. They work together to undertake important tasks of disaster prevention and alarming.

Fire detection alarms are important in the fire automatic alarm system and related to the Integrated Wiring System. This article briefly introduces the current situation of fire detection alarms.

1) Types and connection modes of fire detection alarms

Fire detection and alarms are short for fire detectors or fire alarms, commonly known as probes. They are an important part of the fire automatic alarm system and are distributed throughout all important parts of the Intelligent Building, it is the "sensory organ" of the automatic fire alarm system, which closely monitors and detects the surrounding environment at any time and anywhere.

It works in concert with fire alarm control devices, and automatic fire alarm control devices are the "body" and "brain" of the automatic fire alarm system, which are also the core of the system, they are an inseparable combination that complements each other.

① Types of fire detection alarms

Currently, there are a wide variety of fire detection and alarm types produced at home and abroad. Therefore, there are many different types of fire detection and alarms, which are not uniform yet. They vary according to their technical performance and usage requirements, and they are different. For example, they are classified according to the parameters of the fire detection and alarm, sensitive smoke, temperature sensing, photosensitive, combustible gas detection, compound and other types;

For example, the classification based on the structure model can be divided into two types: point type and line type. If the classification is based on the Use environment, it can be divided into land type, marine type, cold-resistant type, and acid-proof type. Alkali and explosion-proof models. The above types can be subdivided into different types. Fire-induced parameters are generally used in China.

② Fire detection and alarm system and Connection Method

The fire detection and alarm subsystem is the most important part in the fire automatic alarm system and fire-fighting linkage control system. It has the widest distribution of cables, because the fire detection alarm is set to be located in all parts of the intelligent building, and it is compatible with the protection object level.

Therefore, the number of cables (that is, the number of wires) and Connection Methods of the fire detection and alarm subsystem are extremely important, and they are also related to the distribution and utilization of cables in the Integrated Wiring System.

The Wire System of the fire detection alarm mainly refers to the number of wires in the transmission signal line between the fire detection alarm and the control device, which is divided into two types: Multi-wire system and total-wire system. Different connection modes are derived from different wires, including two-wire, four-wire, multiple-wire (n + 4), and two-wire and ring network connections.

In addition, there are thousands of connections such as chain. The above network structures, wires, and connection methods have their own characteristics and are associated with each other. Therefore, in general, it is based on factors such as the size of the detection alarm area in the intelligent building, the distribution and configuration of the fire detection alarm, select the corresponding network structure, wire system, and connection type.

Multi-Wire

The multi-wire system is an early connection method for active detection alarms. It features a live detection alarm (or a group of several fire alarms) to form a loop connected to the fire control device. When any detector in the circuit detects the fire, it reflects the circuit of the detector on the control device and cannot determine its specific personal pity location (that is, the fire point ), therefore, each detector must be connected with a single line to form a multi-wire system. Multiple wires are "n + 4 wires, n is the number of detectors, and 4 is the public wires. They are power cords (V, ± 24 V), and ground wires (G) signal line (S) and Self-diagnosis line (T ). In addition, each detector has an optional line (ST ).

Only when a selected cable is in a valid electric period, the signal transmitted on the signal line is the status information of the detection site. The advantage of this connection mode is that the circuit of the detector is relatively simple. The observation information is more intuitive, and it is easy to determine the specific location of the fire. The disadvantage is that the number of wires is large, the pipe diameter is thick, the threading construction is difficult, and there are many line faults. As a result, the domestic system and connection methods have been gradually reduced.

Total Wire

An independent address circuit is used to determine the specific location of the fire. The alarm control device uses serial communication to access each detector. The number of wires in this type of wire connection mode is significantly reduced, and the installation and construction are simple. Therefore, this mode is widely used. However, once a short circuit fault occurs in the bus circuit, the entire circuit becomes invalid and cannot work normally. It may even damage some detectors or control equipment.

Therefore, in order to ensure the normal operation of the entire system and avoid accidents and minimize the maximum loss, short-circuit isolation measures must be taken in the system, such as the installation of short-circuit isolator in segments.

The four bus lines provide the power supply, coding and site selection signals of the detector on the P line, and the self-check signals on the T line. In order to determine whether the probe location or transmission signal line is accessible, the control device obtains the information of the probe location from the S line, and the G line is the public ground line.

The four lines P, T, S, and G are connected and connected in a ten-thousands way. Because the main wire system uses the encoding Site Selection technology, the control device can accurately determine the specific location of the fire detection, simplify installation and debugging, and greatly improve the reliability of system operation.

The two-wire system uses less lines than the four-wire system, but the technology is more complex. Difficulty increases. In the two-wire system, the P-line is used for power supply, site selection, self-check, and Information Retrieval. The G-line is the public ground.

Currently, this mode of wire and connection is widely used.

Its network structure is tree and ring. Tree type, which is commonly used by most systems. The ring type has four cables for the control device.

In addition, there is also a chain connection type, its P line is connected in series with various fire detection alarms. Each detection alarm has three wires, and only two wires are connected to the control device.

From the various connection methods described above, we can see that, in addition to figure 3.10 (d), the network forms a ring type and provides safe and reliable conditions to ensure normal operation, other bus systems have the disadvantages of poor security and reliability of the bus. Therefore, the advantages and disadvantages must be weighed during the design and determined comprehensively.

2) Relationship between automatic fire alarm system and other systems

In order to ensure the national property is not lost and the safety of people's lives. It is required that intelligent buildings and intelligent communities, especially key departments and important places, must be set and configured with effective disaster prevention and fire suppression facilities that can detect fires in a timely manner, quickly and automatically trigger alarms, and jointly control various functions.

Therefore, an automatic fire alarm system, a fire linkage control system, and a fire communication system must be set up. Considering the construction scale, intended audience, and coverage of Intelligent Buildings and intelligent communities. Therefore, the construction scale and specific content of the above three systems are also different, but the fire communication system is an indispensable part.

They are combined to give full play to their overall functions of timely alarming and fire prevention. Therefore, the fire communication system should be the infrastructure of Intelligent Buildings and intelligent communities, and must be paid attention to and off-duty.