Fire alarm: connection diagram, installation, principle of operation. How do fire alarms work? Typical fire alarm switching diagram

A fire alarm is an indispensable piece of infrastructure these days, allowing you not to worry about the integrity of the premises even if no one is monitoring its condition at a particular moment. This system is especially good in those buildings where the likelihood of a fire occurring and quickly spreading is significantly increased. Initially, the installation of such equipment made sense exclusively in various warehouses, but today the reduction in the cost of such products leads to the fact that they are gradually moving into the household category - after all, flammable materials are increasingly being used in the decoration of apartments.

How the system works

Fire detectors are a whole group of different devices that, when combined into a fire protection system, respond to potentially dangerous phenomena. Depending on the exact configuration, the system detects a particular problem and sends information about it to the fire department, which is able to arrive on the scene even before being called and save property and people. Addressable-type sensors are capable of not only signaling the presence of a problem in the surveillance area, but also accurately displaying on the remote control the point at which this problem is detected. For the people themselves, the system can provide an automatic sound warning - since something has caught fire somewhere and the firefighters are about to arrive, it makes sense to leave the building.

The fire notification system for each room is assembled individually, taking into account its design features and potential threats. In this case, different types of sensors are used, which have different operating principles.

• Heat detectors respond to rising temperatures. Threshold ones are considered the most accessible and common, but they are not always effective - the sensor responds to temperatures above 70 degrees, which cannot normally be, but if the source of fire is far away, the response will be delayed. Integrated detectors are more reliable in this sense, but they are also more expensive. Thermal sensors can be linear - then they are presented in the form of a cable, not a point. And they control a long line.

• Smoke detectors have long been considered mandatory in public spaces. They emit infrared rays, which are scattered even by a small amount of smoke, which is detected by the device. Such a system is reliable in terms of response, but there are too many possibilities for false alarms - the device can mistake steam or even dust flying in the air for smoke. Naturally, it makes no sense to install such a system in a smoking room, but it is there that the probability of a real fire is quite high. Accordingly, smoking is strictly prohibited in any premises where there are such sensors.

• The flame detector reacts when a fire appears, and not to accompanying factors. Best use for such a sensor - a production room where there is a lot of dust and constantly high temperature, and there are also flammable materials. The above-described detectors would either have regular false alarms, or they would have missed the sharp moment of the fire, and while they were “thinking,” the flame could have engulfed the entire workshop.

• A gas leak detector can often respond to both smoke and temperature, but him main feature– “feel” the smell of gas, even when a person has not yet detected it. A leak usually leads to devastating consequences in the form of an explosion, so if it is detected, immediate action is required, and an alarm will trigger emergency service, even if no one is there.

• Combined sensors are able to respond to several criteria at once, and therefore can potentially be considered the most effective.

How to choose a place?

The efficiency of the system depends on how correctly the sensors are located, so you should focus more on the configuration of the room rather than on the standards, which are quite liberal in this regard. Thus, sensors should not be further than 9 meters from each other, and no more than 4.5 meters from the wall. There must be at least two sensors in the room, since this way they insure each other and cover the territory more completely. If the detectors are placed not on the ceiling, but on the wall, there must be at least 2 meters of distance between them, since otherwise a so-called smoke pocket will form, due to which the frequency of alarms will sharply increase. For the same reason, if the ceiling has protruding beams in the form of partitions, catchers are placed not in the spaces between them, but on the beams themselves.

Any sensor has a certain level of sensitivity and does not always cover the entire hemisphere– it must be installed either so that it covers the entire protected space, or with a special focus on the potentially most dangerous places, for example, constantly running computer technology. IN small rooms Usually, a further location of the sensor from the source is allowed, since the same smoke or elevated temperature simply has nowhere to escape from four walls.

For example, a flame detector at a distance to the fire of more than 9 meters is unlikely to detect a problem at all. In a room up to 15 sq. m, it will still react at a distance of 6-9 meters, but with a doubling of the room, the distance from the fire to the sensor should no longer be more than 3-3.5 meters.

It’s easier with smoke - the same minimum distance to the detector is suitable for rooms of 70-85 square meters. m, and for areas less than 55 sq. m detection is possible even at a distance of 10 meters. In rooms equipped with a false ceiling, the installation of detectors has its own characteristics.

Placement already behind a suspended ceiling is possible only under several conditions: presence of perforation on suspended ceiling with a total area of ​​about 40% of the surface for a good “view” of ceiling sensors, the diameter for each hole is not less than 1 cm, or creating a suspended structure from parts whose dimensions do not exceed the coverage area of ​​one sensor. Accordingly, detectors are usually attached to the main ceiling or other reliable structures, and are embedded into the ceiling. If compliance with these conditions does not seem possible, ceiling sensors are placed on the walls, since directly on suspended structures they cannot be attached due to the fragility of the latter.

Step-by-step installation instructions

Ideally, installation should be entrusted to professionals - only they know all the rules and regulations, are able to correctly calculate distances and select the most effective sensor placement scheme. Experience allows craftsmen to avoid popular mistakes of inexperienced people, when when calculating the number of ceiling detectors, the position of the lamp is not taken into account, which interferes with the view or causes false alarms due to heat generation. However, you should still have a superficial understanding of the topic, at least in order to check the quality of the work being performed.

When the plan is drawn up taking into account all the standards described above, it is necessary to place markings on the ceiling or walls in the places where the sensors will be mounted. After this, the diagram should be comprehensively evaluated again, since new details may often be observed on the ceiling that were not taken into account in the drawings. When making changes on the fly, do not forget that all distances must be in accordance with at least the minimum permissible values, otherwise either the system will not work in the event of a fire or will cause false calls.

They are mounted in the places allocated for the sensors. Connection to the electrical network is carried out in series with two-core wires. All parts must be connected into a single network, therefore a resistor must be installed on the last connected sensor.

When installation is carried out behind suspended or tensile structures, a separate frame can be designed for fire alarms - for example, you can mount them on a cable if it is reliable and well secured. In this case, the insertion should be done so that the edges of the slot do not interfere with the full view of the room by the sensor, therefore, ideally, the latter should be brought to the very level suspended ceiling. If the ceiling is suspended and made of a material that is resistant to even the highest temperatures, the slot should be placed in a special thermal ring, because the sensor itself, constantly connected to the power supply, can also heat up. Final stage– checking the system operation. For most types of sensors, a simple and good test is a lit match or lighter, which is carried along the detectors - here you have flame, smoke, and temperature, so the working system is simply obliged to react.

Connection features

Both in production and in residential buildings The main purpose of fire detectors is not only to detect potential danger, but also to convey a message about it to firefighters. This allows you to urgently respond to fires and smoke before they become catastrophic, even though there may be no one in the room to raise the alarm. Accordingly, the detector must be connected not only to the power supply, but also to a receiving station located directly at the fire station.

Not all fire alarm systems automatically send a message about the situation - some can only trigger a siren, warning everyone present of the problem. So, in places where there are always people, inexpensive manual call points are more often used - it’s like a fire alarm button, someone has to press it. Automatic detectors respond to sensor readings, so the signal is sent without human intervention. In any case, a communication channel and an end subscriber are needed to transmit the signal, therefore, without the direct participation of the fire service, installing a fire alarm makes no sense. The stations to which the detectors are connected are different - they are designed for different types of sensors themselves and usually have a limit on their maximum quantity. For this reason, even in the process of drawing up a system plan, you need to select a suitable station and agree with firefighters about its installation and maintenance.

Connecting detectors to each other is possible both via a ring, or loop, system, that is, in series, and by a radial method, where a separate cable is allocated for each point.

Possible problems after installation

Fire alarms must always be in perfect working order, since the safety of not only property, but also human lives depends on it. At the same time, fire detectors, like any other equipment, can periodically break down, including due to insufficient care. Experts note that the absence timely prevention is one of the most common causes of system failure. For example, dust and small foreign debris may get into the smoke detector chamber; most likely, this will happen sooner or later, and then the detector will no longer be able to respond to smoke in a timely manner.

Accordingly, an indirect reason for the malfunction of the sensors can be the elementary untidiness of the service room. We have already mentioned that different types of sensors are capable of false alarms due to dust, elevated temperatures and even high humidity. It is clear that in the conditions of a production workshop, it may simply not be possible to significantly improve the conditions, but then you need to take a more responsible approach to choosing the type of sensor and choose one that will not react to the natural conditions of the protected area like a fire.

An eternal problem, and a serious one, remains the intervention of unqualified people at any stage. When installing, you need to check the certificates and make sure in any way possible that your installers are smart people. It is strictly not recommended to install a fire alarm yourself - if you do this, the responsibility falls entirely on you. It is also unacceptable to try to fix minor breakdowns, even if they seem completely solvable - in this case, you should call specialists.

Like any other system, a fire alarm system breaks down over time due to wear and tear - it usually has a lifespan before all its parts will have to be replaced, even if it still responds to the irritant when tested.

All other reasons are usually quite banal and are associated with the failure of one of the nodes, not even directly part of the system - for example, in the absence of electricity, the network system, of course, does not work. Due to careless handling, the power cables or the communication channel with the fire control panel may be damaged, the cable may fail, or the siren alerting those present may break. A purely software failure in the form of an incorrect date and time is also possible, which can result in more serious consequences.

A properly installed fire alarm is the key to the safety of your property and your own safety. On modern market several effective systems, working on different principles. Explore the features of the available options, select the most suitable type of fire alarm, and then read the guide for calculating and installing sensors and what to do in case of a false alarm.

There are systems that use smoke and heat sensors. The principle of operation of the devices is clear from their name: thermal sensors They are triggered when the temperature rises, while smoke alarms are activated when smoke forms within the range of action. The sensors can be directly powered by special control and control devices or batteries.

Good for home addressable analogue system, and address-interrogation signaling. Installations of the addressable survey type find fires as quickly as possible. Modern addressable analogue alarms are able to determine the location of the fire and even take some actions, for example, turn off the ventilation system, close or open everything in the house, turn on an audible alarm, etc.

Modern ones are available for sale fire alarms with built-in GSM transmitter. In the event of a fire, such a system will call or send an alarm message to a specified number. This will give the owner the opportunity to immediately call the fire department and personally come home. Modern GSM systems can be programmed to notify several phone numbers at once, which is very convenient.

The nuances of installing and maintaining a fire alarm system

Fire detectors must be installed on every floor and in every room of the house. Attics and basements are also no exception. The best place to place fire alarm sensors is the ceiling.

You can install the sensors yourself, but if possible, it is better to entrust this work to a licensed company.

Once installed, the alarm system will require regular maintenance. If the sensors are powered by batteries, check the functionality of the controllers every month. The batteries themselves usually use up their life in a year. It is recommended to replace the sensors with new ones at least every 7-10 years.

If the system elements are powered by a lithium battery, the sensors must also be tested monthly. If it is necessary to replace the battery with a new one, all warning devices must be replaced at the same time.

If your apartment or house has a wired system, check its serviceability every month. The power supply needs to be changed annually. The service life of the entire system is on average 7-10 years.

During the installation process fire system pay special attention to the cross-section and location of the cables. Consider the fact that in the future you may want to redesign rooms or make basic repairs. Try to think things through so that any repairs can be performed without making changes to the alarm system configuration.

Ensure reliable protection of the system from various types of unacceptable external damage (damage from insects, chemicals, etc.). The norms and rules for installing the systems in question are dictated by the relevant GOSTs. Carefully study the current regulatory documentation before starting installation work.

Buy equipment only from verified and licensed suppliers. Alarms of dubious manufacture usually behave unpredictably. For example, they often operate without any hint of a fire, but during a real fire they remain stubbornly silent. Therefore, do not skimp on your own safety and buy a quality system from famous manufacturer. All the same, the alarm system will not have to be replaced very often.

After installation, have your alarm serviced. To do this, it is better to contact a specialized company.

In preparation for installing a fire alarm, a number of special calculations must be performed. They will help you choose the most best option systems and avoid unnecessary costs during installation and maintenance of sensors.

One of the most important stages of alarm calculation is Determining suitable power supply capacity. Decide which energy source will be most convenient for you to connect the sensors to. There are quite a lot of such sources: from ordinary batteries to solar batteries.

The required battery capacity is indicated in the instructions for the alarm. Check the value found with the information on the battery case. If the battery capacity is not enough, purchase a more powerful battery or connect several batteries in parallel.

When parallel connection multiple batteries, make sure their voltage is the same. Otherwise, the total capacity of the battery circuit will decrease.

Check the required wire cross-section for connecting fire alarm sensors. This information is usually provided in the system manual. Also pay attention to indicators such as battery capacity for standby and alarm modes. Add these values ​​up and you will get the total required battery capacity specifically for your system.

Connecting an alarm using the example of typical sensors

First stage. Determine the required number of alarm sensors. To determine the required number of controllers, you need to know the area of ​​the room served and the ceiling height. In the current regulatory documentation it is said that if the ceiling has a height of no more than 350 cm, then one sensor is sufficient to service 80 m2. At the same time, fire safety rules require that even in the most small room there were at least two controllers. Follow the last rule.

Second phase. Mark locations for installing fire detectors. Maximum permissible distance from the wall to the sensor regulatory documents is 450 cm. The sensors themselves must be installed in increments of at least 900 cm. This rule is relevant for situations where the ceiling is single-level and its height does not exceed 350 cm.

Wall-mounted models of fire sensors should be placed at a distance of 200 mm from the ceiling surface.

Third stage. Fix the sensors at the marked places and connect them to the power source using two-wire wires. The sensors are connected to each other in series. You need to install a resistor in the terminal block of the last controller.

Fourth stage. Test each sensor after connection. To do this, light a candle and pass its flame near the detector.

If the fire alarm goes off without any sign of a fire, you need to follow a few simple steps to turn it off. Otherwise, loud sound alerts and unnecessary triggering will occur. additional funds will cause you a lot of trouble.

First option. Find out why the alarm went off in the first place. You cannot turn off the system without first checking all serviced premises. High-quality systems extremely rarely work without any reason. Maybe there was smoke or a real fire in some room of the house. If there is an “irritant”, eliminate it, and the system will turn off on its own. Be sure to check the condition of the electrical wiring.

Second option. If you have not found any reasons for the alarm to go off, proceed to turn it off. The shutdown procedure depends on the type of specific system. The simplest option is to disconnect the alarm from the power source. However, this option can be considered solely as a temporary solution to the problem, because With a disabled alarm, you are jeopardizing the safety of your home and everyone in it.

Third option. If your home has a centralized control panel, turn off the alarm from it. In some situations, this procedure requires entering a special code. If you don't know it, contact the company that services your fire alarm.

Fourth option. If the controller becomes very dusty, for example, during repair work, to disconnect it, it will be enough to remove the front panel from the sensor and rub its “insides” with a cotton swab slightly moistened with alcohol. If this was the problem, after such cleaning the alarm will turn off. From now on, monitor the condition of the sensors and clean them promptly.

Fifth option. If it is necessary to turn off the fire alarm in any separate room, you can wrap the sensor with adhesive tape. However, after such processing the controller will become useless. Remove the tape immediately after identifying and correcting the problem.

Sixth option. If none of the above helped, use the most radical solution - cut the wires connected to the sensor. The fire alarm will turn off, but will become completely useless until you repair it. Try to figure out the cause of the false alarms of the sensors as quickly as possible and eliminate the malfunctions.

If this is possible, contact a specialized company. Its employees will diagnose the fire alarm and give recommendations on further actions on your part.

Thus, in self-installation There is absolutely nothing complicated about fire alarms. You just need to understand in detail the sequence of connecting the sensors and follow the instructions. Be sure to check the manufacturer's recommendations. Many modern systems have a number of features that need to be clarified separately. Your safety depends on the correct installation and connection of sensors, remember this.

Good luck!

Video - DIY fire alarm installation

Installation of fire detectors certainly implies their connection into a fire alarm loop. The connection diagram for fire detectors is given below. Two-wire (most commonly used) are considered

• fire smoke detectors (DIP),
• thermal fire detectors (IP),
• manual fire detectors (IPR).

Connection diagram security detectors is shown on another page.

A fire alarm loop can simultaneously contain detectors of one or more (combined alarm loop) of the specified types. In addition, the connection diagram for fire detectors may provide for the activation of a fire alarm control panel (generation of a “fire” notification) when only one fire alarm loop sensor is triggered or when two or more fire detectors are triggered. (such organization of the fire alarm loop after the activation of one detector generates an “attention” signal).

Addressable fire detectors also have their own connection diagram. I would like to note that the connection diagram for fire alarm sensors may vary (depending on the type of control panel), however, the differences are insignificant, mainly affecting the ratings (values) of additional (ballast), terminal (remote) resistors.

In addition, different types of control and monitoring devices allow the connection of a different maximum number of smoke fire detectors in one alarm loop - this value is determined by the total current consumption of the sensors. Remember, the current consumption of a smoke detector depends on its type.

All types of non-addressable two-wire smoke detectors use the same pin numbering: (1,2,3,4).

The connection diagrams for the terminals of smoke detectors from different manufacturers may visually differ slightly (options 1, 2), but, from an electrical point of view, they are identical, because inside the detector housing, terminals 3, 4 are short-circuited.

However, the second option has serious drawback- when removing the detector from the socket, the receiving and control device will not detect its absence and will not generate a “fault” signal. Therefore, it is better not to use it.

Note!

• Even for one specific type of fire alarm control and control device, resistors Radd. may have different values ​​(determined by the current consumption of various types of smoke detectors, read the device data sheet carefully).
• Connection diagram shown fire manual call point is valid when its executive element is normally closed electrical contacts. For example, for IPR 3 SU this connection diagram is not suitable.
• Thermal fire detectors are connected according to the above diagram if they have normally closed contacts (the majority of them).
• A situation may arise when an IPR, connected according to the above diagram (recommended in the device data sheet) for an alarm loop that provides for activation by two sensors, when triggered, causes the receiving and control device to generate an “attention” signal instead of a “fire”. Then try to reduce the value of the resistor (Radd), through which this IPR is connected to the alarm loop.
• Before connecting (installing) addressable detectors, their address must be pre-programmed.
• Connecting smoke fire detectors requires compliance alarm loop polarity.

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Almost every day we hear the howl of fire brigade sirens on the street. This confirms the statistics of a large number of fires, both apartments, private houses, and production premises. The causes of fires are carelessness in handling fire, smoking in the wrong place, short circuits in wiring, sparking equipment, etc. An automatic fire alarm can warn of a fire, the equipment of which includes smoke detectors, an audible alarm and a remote control for transmitting a fire signal to the central fire department post.

What is a fire alarm

For timely detection of the first signs of fire, primary recording devices (sensors) are needed that can quickly detect the appearance of smoke. Such a sensor can itself emit an alarm signal or activate an automatic warning system for people in the building, turn on the fire extinguishing system and transfer the call to the emergency rescue unit of the Russian Ministry of Emergency Situations. The entire described set of technical means of primary detection and information about this is a fire alarm (FS).

Proper configuration and periodic compliance checks of fire detection systems are very important. With prolonged use, sensors become dirty and lose their properties, and the lives of people and the safety of property depend on their performance. Quick fire detection and deciphering information about the location of the fire can solve many problems:

• turn on fire extinguishing or call the fire brigade of the Ministry of Emergency Situations;
• evacuate people;
• prevent the spread of fire;
• reduce the financial consequences of a fire;
• minimize injuries and deaths.

Device

The PS block diagram includes sensors whose purpose is to signal the appearance of smoke, a system for collecting, monitoring and transmitting information from them. Each element of the PS is responsible for solving its own problem:

• Security and fire panel – includes fire and security systems.
• Sensors - must detect smoke and give a signal.
• Reception and control panels – provide collection and processing of information, generation of signals to the relevant services.
• Peripheral devices – provide power supply, communication lines, information methods, fire extinguishing activation.
• Equipment for central control of fire and security alarms (FSA) – receives signals from various objects and generates information for the fire departments of the Ministry of Emergency Situations.

Principle of operation

The fire alarm system operates on the principle of polling all sensors in turn and identifying the fact of activation (for threshold systems), or changes in the level of controlled environmental parameters (for addressable analogue systems). In simple threshold systems, when the sensor is triggered, the entire loop breaks, which signals a fire in the area where this loop is located. In automatic fire extinguishing systems, a signal turns on irrigation in the smoke zone, sounds an alarm and makes a call to the central control panel.

Types of fire alarms

Modern substations are made from various components. The principle of fire alarm operation affects the choice of the necessary equipment - detectors, cables, power supplies, etc. According to the principle of constructing PS there are:

• threshold with radial loop;
• threshold with a modular structure;
• targeted surveys;
• addressable analogue;
• combined.

Analogue addressable system

To collect and analyze information from smoke, temperature, humidity, etc. sensors, addressable analogue substations are created. Each sensor is assigned its own address of location in the building and information about its readings in real time is read through the loops by the control panel (PKP). By analyzing information from several sensors, the addressable alarm system determines the location of the fire and sends a signal about the fire. Addressable signaling loops have a ring structure. You can connect up to 200 devices and sensors to one loop:

• automatic fire detectors;
• manual call points;
• relay;
• sirens;
• control modules.

Advantages of addressable analogue PS:

• early detection of the outbreak;
• few false alarms;
• possibility of changing sensor sensitivity thresholds;
• low costs for installation, commissioning and maintenance.

Targeted survey

Unlike the addressable analogue system, in the addressable and threshold systems the generation of a fire signal is carried out by the sensor itself. At the same time, an information exchange protocol is implemented in the loop to determine which sensor was triggered. The operating algorithm is simpler than in an addressable analog system. The control panel waits for sensor signals, cyclically polling all fire detectors to determine their status. Their disadvantages include an increase in the time of fire detection. The advantages of such PS are:

• information content of the signals received by the central post;
• monitoring the functionality of fire detectors;
• favorable price-quality ratio.

Threshold

The construction of a fire system in which each sensor-detector has a configured specific sensitivity threshold is called a threshold PS. In it, the activation of one of the sensors generates an alarm signal based on the loop number. These fire systems are used to control small objects - shops, kindergartens. Their disadvantage is that they contain little information (only the sensor response signal) and do not indicate the location of the fire. The advantages include the low cost of such a system and its installation.

Fire alarm sensors

The main function of fire sensors is the ability to quickly respond to changes in the physical parameters of the environment. PS sensors differ from each other in the type of physical parameter being monitored, operating principles and methods of transmitting information to the central control panel. The principle of their operation can be passive - only actuation, and active - actuation plus control of parameter changes environment. Active detectors, depending on the level of threat, send signals of different levels to the automatic control post (AUPS).

Aspiration types of detectors perform remote sampling of air in a controlled room, delivery and analysis of it in a separate device. The main difference between sensors and each other is the type of control of physical parameters, according to which they are divided into:

• smoke;
• thermal;
• flame;
• water leaks;
• carbon/natural gas leaks.

How does a smoke detector work?

A smoke detector (or smoke detector) is designed to identify the source of a fire by detecting smoke in the part of the building where it is located. The sensor operates on an optical principle - light from the LED, entering the photocell through the air chamber, generates an electrical signal of a certain level. When the air chamber smokes, the beam from the LED is scattered and less light reaches the photocell. This is a sign of smoke and the sensor generates an alarm signal. The sensor operates in a temperature range from minus 30 to plus 40 degrees.

Installation Standards

Fire alarm installation is carried out in accordance with the official document - fire safety standards NPB 88-2001 "Fire extinguishing and alarm installations. Design standards and rules" - all rules for the design, installation and operation of such devices are approved. These rules govern the creation of various fire extinguishing systems. For example, the number of smoke point sensors and their location relative to each other depends on the area and height of the ceilings of the room:

Height premises, m	Average area, controlled by one sensor, m2, up to	Maximum distance, m
		between sensors	from the sensor to the wall
from 3.5 to 6.0
from 6.0 to 10.0
from 10.5 to 12.0

Fire alarm installation

At the first stage, you need to select the type of PS, the manufacturer, the cost of the most basic and necessary additional equipment. PS is often combined with a security system, resulting in security and fire alarm(OPS). The implementation and installation of an automatic fire alarm (AFS) at the site of the fire safety system chosen by the customer includes several stages:

• fire protection system design;
• laying cable loops;
• installation of sensors;
• commissioning works.

Fire alarm price

It is very difficult to estimate the costs of design, installation and commissioning of a substation. You can buy these systems in specialized showrooms in Moscow, St. Petersburg and other Russian cities. They are sold by online stores. You can roughly evaluate and compare several similar systems by considering a very rough list of fire system equipment from two different manufacturers to protect a two-story, five-room house without an attic or basement:

It is impossible to be prepared for a fire; it is always sudden and uncontrollable. But it is possible to minimize the risk of its occurrence by significantly reducing predictable material damage. For this purpose, experts have invented fire detectors, which are currently the only means capable of detecting a fire without a person. One of these is a thermal fire sensor or detector, briefly TPI.

The name itself - thermal - explains the principle of operation of the device. It contains one or more transducers - sensitive elements, which, sensing a temperature increase in the environment, lead to the activation of a loud identification signal through an audible alarm.

There is another type of detector - a fire smoke detector. It triggers on aerosol combustion products, in other words, smoke, or more precisely, its color. The advantage of fire-fighting smoke detectors is that it is allowed in administrative buildings, unlike a heat detector, but the disadvantage is that it will wake everyone up not because of a fire, but, for example, a large accumulation of dust or steam. Moreover, strictly speaking, calling it a sensor is incorrect, because it is only an integral part of the detector.

Main types

Based on the type of the main component of the TPI - the sensitive element or controller, there are four main types:

• Contact TPI. When it changes temperature regime the established contact or the electrical circuit opens, the special cable breaks and causes the sound signal to sound. The simplest, usually domestic models, are a closed contact of two conductors, packaged in a plastic container. More complex ones have a temperature-sensitive semiconductor with negative resistance. If the ambient temperature increases, the resistance will drop and a controlled current will flow through the circuit. As soon as it reaches a certain point, the alarm will go off.
• IN electronic sensor sensors are installed that are located inside the cable; as soon as the temperature reaches a certain threshold, the resistance of the electric current in the cable changes, which is transmitted to the control of the control device. Highly sensitive. The principle of the device is quite complex.
• Optical detector works on the basis of fiber optic cable. As the temperature increases, the optical conductivity changes, which leads to an audible warning.
• A metal tube with gas, hermetically filled, is necessary for mechanical TPI. The effect of temperature on any part of the tube will lead to a change in its internal pressure and trigger a signal. Deprecated.
• Other types. Semiconductor ones have a special coating with a negative temperature coefficient, electromechanical ones consist of wires under mechanical stress coated with a heat-sensitive substance.

Types of fire detectors

Firefighters respond to different parameters of fire spread. Hence the classification into types.

The absolute value threshold is set in the maximum fire sensor:

• pressure,
• temperature - as soon as the ambient temperature reaches it, people will be notified.

Domestic devices with an operating temperature of 70-72 degrees are produced en masse. They are also very popular due to their financial accessibility.

For a differential fire alarm sensor, the rate of change of the sign that it monitors is important.

Such devices are recognized as more effective than maximum TPI -

• give the alarm earlier
• They are stable in operation, but due to two elements installed at a distance, they are higher in price.

Maximum differential devices combine both parameters.

When planning to purchase this type of fire-fighting devices, keep in mind that their temperature threshold must be at least 20 degrees higher than the permissible temperature at the facility.

Thus, technical specialists divide modern fire alarm systems into discrete (based on threshold) - they are discussed above - and analog. Analog thermal fire sensors, in turn, are divided into non-addressable and addressable. The latter transmit not only information about the fire, but also their address code.

Both discrete and analog measure the characteristics of fire factors; the fundamental difference is in the method of signal processing.

For analogues it is more complicated and its essence lies in special systematic algorithms.

• Analog Addressable Thermal Devices regularly collect information about the condition of the premises. They can produce the data they are programmed to collect in real time.
• Explosion-proof thermal fire detectors are needed where the risk of fire is high and explosive substances may be present in the air. They seem to be armored, as they are located on various power units, oil pipelines, etc. They differ in the degree of protection, the number of sensors and different set temperature thresholds.
• U linear heat detectors a cable with a heat-sensitive polymer is used - a thermal cable - it records any changes along its entire length as a single fire sensor. Used where the ceiling is large, such as an indoor stadium. In addition to the ceiling, you can also mount it on the walls.
• Multipoint thermal devices opposed to inherently linear. They are part of a single system that controls several zones and is combined into an electrical circuit. Signals received from fire sensors are processed in a single unit.

Operation and Installation

The connection diagram for thermal sensors is given in the operating instructions, however, difficulties may arise.

The requirements of GOST R 53325-2009, paragraph 4.2.5.1, require thermal detectors to be equipped with a built-in or remote optical indicator.

When calculating the values ​​of additional resistors, take into account the electrical components of the connected LED indicators.

Look in the device passport for the typical and maximum voltage drop, which indicate the limit of the parameters. For ease of installation, it is better to use LED non-polar indicators.

Normally closed contacts of thermal devices are connected to the loop in the same way as for smoke devices. The difference is that in the standby state, thermal sensors do not consume electric current, and in active mode it is less than that of smoke sensors.

Fire alarm thermal sensors have the following resistances in the connection diagram:

• Rbal.,
• Rok.,
• Radd.

We study the operating instructions for the monitoring device and take into account the resistor values.

Rbal. similar to Radd., but it is not included in the control device kit; you will have to buy it additionally.

In normal mode, the sensors are short-circuited, which means that resistance Rbal will appear only if one or two of the devices operate. And then an “Alarm” signal can be generated.

For controllers “ Mirage” there is the following diagram. If one is triggered, the “Attention” signal will be received, if the second one is triggered, the “Fire” command will follow.

The designation of the heat detector in the diagram, as well as other components, is as follows:

• Shs– alarm loop,
• IP- thermal fire detector,
• YPRES– manual fire detector,
• DIP– fire smoke detector.

Conditional graphic designation automatic heat detector according to the requirements of regulatory documentation - .

Standards and features of installation/connection of thermal sensors are regulated by water rules of fire protection systems 5.13.130.2009 with the latest amendments from 06/20/2011.

From Table 13.5, the distance between the thermal point devices, as well as between them and the wall, becomes known (do not forget about the exceptions specified in paragraph 13.3.7).

Thanks to modern technologies Today it has become possible to remotely control security equipment. Mechanical control has been replaced by automated systems. People began to completely trust technology, since the human factor is not applicable to it.

Purpose and functions of the fire alarm panel

A centralized system helps to monitor the protected object, even if you are far from the object and are unable to take action active actions. A message about smoke or fire is immediately sent to the control panel, which is a signal for an immediate response.

• The previous generation of centralized systems were ineffective.
• Modern electronic systems, compared to their predecessors, consume minimal energy with maximum efficiency.
• Remote control of the fire protection system makes it possible to obtain information about the operation of the alarm, as well as determine the exact location of the smoke or the source of the fire.

By installing a centralized fire safety system, you can use the control panel to control fire extinguishing units, check the device for operability, and perform other actions if such a need arises. In the event of an extremely dangerous situation or a threat to human life and health, the indication on the control panel lights up and turns on as a warning sound signal, reporting danger.

• The functionality of the control panel depends on the type of fire safety system and the selected model.
• The standard configuration consists of a light panel with bright light emitting diodes and control keys. The diode panel is connected to the receiver and the loops from the signaling devices.
• Depending on the blinking frequency of the indicator, you can determine the current state of the sensor.

To install the systems control panel, a special room is allocated - a fire station. The specified premises must be provided with round-the-clock surveillance by duty personnel. The duty officer must always monitor the status of the indicators on the control panel: all fire extinguishing directions, automatic and remote security start modes, control blocking. The number of indicators varies depending on the selected remote control model.

Main functions of the remote control:

What is a control panel (RCD) and its purpose?

The fire alarm control panel (FKD) is the most basic part of the control of the entire fire protection system. Responsible for fire protection of protected facilities.

In the event of a threat to human life, it is possible to monitor door status sensors, manually start fire alarms, control motor drive circuits and ventilation valves, and control elevators. To manage additional sensors, a professional system setup is required.

Depending on the type, the control panel can control one or several fire extinguishing locations at once, distinguishing them by the type of substance that neutralizes the fire.

Types of PKP according to the size of the working capacity

small capacity control panel

They are used when installing systems on small objects, for example, in private houses, in country houses. Two types of incident notifications are played. The advantage of such systems is their simple design and the absence of special skills during installation.

When choosing a control panel, you need to pay attention to the wide use of alarm loops and the possibility of changing their functions. Also, you should not take cheap control panels; it is better to rely on the functional features, area and number of floors of the building and its fire hazard. The amount of energy expended by the PKP plays a significant role. For standby and emergency modes, the value should be minimal, since productivity depends on this.

Monitoring devices for medium and large information capacity

Large buildings ( shopping centers, warehouses, production, etc.), in contrast to small structures (for example, Vacation home), require multi-stage fire alarm equipment.

If necessary, organize a unified (general) management of the protection of the building and fire safety install devices of medium and large information volume with the number of messages from 3 to 5 and above 5. In the case of installing the specified capacity of the control panel, it is important to take into account the possibility of increasing the volume in the future.

The difference between a regular twisted pair cable and an RS485 system is that using the RS485 interface requires special skills and careful attention to the type of connecting lines, while a regular twisted pair cable can be installed on your own.

Particularly convenient in this system is the ability to use a PPK remote control instead of a computer.

Pre-thought out and planned in detail Technical equipment premises will help reduce future costs in the event of a possible increase in the area of ​​the facility.

System price

The average cost of quality systems varies between from 2000 to 7000 rubles.

1. The most popular models of automatic fire protection systems among consumers are models such as From 2000-M with a wide range of options and the ability to connect up to 32 loops. Attractive with its compact size and sufficient performance. The cost of such a device varies from 6800 to 7800 rubles.
2. The next not uninteresting specimen is Signal-10. Increased operating temperature range +50 degrees Celsius. Its cost is approximately 2000 rubles.
3. More efficient at high temperatures up to +55 degrees and at the same time, the model is quite compact for its performance S2000-M Control and Control Panel. The price of such pleasure is approximately 6300 rubles.

The history of the development of security alarms goes back many years more years than is commonly believed. An example is the ancient diagrams of original inventions, such as the Japanese “singing floors”, the “Dionysian ear” from ancient Greece, or the Egyptian secret traps designed to ensure the safety of the treasures of the pharaohs. The first prototypes of modern security alarms began to be developed along with the advent of photocells and the electric bell.

Modern technologies provide the opportunity to choose a security alarm among many different options. Such systems use the most different types and equipment combinations. However, in this diversity there is a common logic, and therefore it is possible to describe a general simple security alarm system, which allows us to get a certain idea of ​​​​its design and operating principles.

The equipment diagram of any security alarm system includes the following components.

Security alarm detectors. Depending on the project, different types of detectors can be used. The most common options are infrared (passive or active), photoelectric, magnetic contact, and detectors that respond to sound, glass breakage or temperature changes.

Controller. This is a key component of a security alarm system, collecting and analyzing signals from all detectors in the system, and also triggering it when strangers enter the protected area. At the same time, the controller displays information about the incident on the display or other data display device.

Executive device. By using of this element the system reacts to a violation of the security circuit. Modern alarm systems are equipped with a wide variety of actuators, including sound (sirens, bells, loudspeakers), communication (notifying an alarm via radio channel or cellular communications), visual (light panels, flashing beacons) or active, for example, blocking exits and elevators.

Power supplies and communication lines. These elements serve for power supply (including autonomous) and communication between the elements of the security system.

A typical security alarm circuit looks like this.

Active infrared motion detectors and passive magnetic reed switches are used as detectors, triggering the system when the doors are opened. Actuating devices are sound and visual (light) indicators (flashlight, siren). The control panel contains components for controlling the security alarm, LED indicators that signal in the background about the integrity of the circuit, as well as a special relay that triggers the mechanisms when the contacts on it are closed actuators. The system is supplied with electricity using a 12-volt uninterruptible power supply. As a rule, security alarms have an autonomous power supply, since dependence on the central network increases their vulnerability to intruders.

Having a general understanding of the principle of construction and operation of a security alarm system, this scheme can be modified and modified using various methods, for example:

• increasing the number of security system circuits that are independent of each other;
• combining detectors of different types and optimizing their localization. In this case, the main task is to eliminate “blind spots” and provide backup scenarios for triggering the security circuit;
• providing additional levels of security, such as backup power supplies for alarms, or methods for quickly restoring the functionality of the security system in the event of a disruption in communication channels;
• integrating burglar alarms with other security systems such as video surveillance, patrol services, fire fighting equipment etc.
• complementing the functions with active security measures that influence violators. Paralyzing gas released into the room through ventilation ducts, floor hatches leading directly into the piranha pool and other techniques from adventure films are extreme examples of such mechanisms. However, not so exotic and dangerous, but similar in principle of action security equipment They are used quite often in reality.

IN absolute majority In cases, measures that complicate the security system are aimed at increasing its reliability and ability to withstand any known methods of undetected penetration or direct intrusion into the protected area. Violators, in turn, are trying to develop effective, fast and invisible ways to bypass all levels of protection.

In any case, this is another version of the confrontation between offensive and defensive means, in which each side must develop continuously so as not to give the advantage to the enemy. For this reason, new technologies and innovative equipment will be constantly developed in the field of security alarms in the future. At the same time circuit diagram security systems will remain unchanged.

The UNITEST company specializes in the manufacture of security and fire safety equipment, as well as the design of security systems.

Fire alarm circuit designed taking into account architectural features building, will allow the most rational and efficient placement of equipment for timely identification and localization of the source of fire. The fire alarm system should include a fire extinguishing system, building ventilation control, and possibly voice warning and elevator operation control.

The security alarm circuit is used to develop a system to prevent unauthorized entry into the building by unauthorized persons. The signaling scheme takes into account cable routing, installation of sensors, control panels and placement of the control system. It is important that the placement of the system minimizes damage caused interior decoration building. This factor must also be taken into account in the diagram.

The fire and security alarm scheme is designed to take into account the location of the integrated security system. It reflects signaling devices, fire extinguishing devices, control units, as well as the location of the access office and video surveillance systems. The scheme is developed taking into account the individual characteristics of the protected object - calculated required amount sensors and devices for powder, gas or water fire extinguishing.

UNITEST company - indispensable assistant in the development of security and fire alarm systems. All products are certified and designed to serve your safety.

It has always been difficult to honestly ensure your well-being, but losing what you have justly acquired in a fire or theft is a shame, and you need to earn money again... A fire and security alarm (FS) allows you to reduce the risk of property loss due to misfortune to a minimum, and the insurance premium rates for housing equipped with it are significantly below. Nowadays, another favorable circumstance has appeared - the installation of a fire alarm can be done by a person familiar with the basics of electrical engineering and household work, and the legalization of a correctly assembled system most often does not require compliance with complex formalities.

Really? OPS is a serious matter; the Ministry of Emergency Situations must respond to an alarm. And by law, the installation of a fire alarm must be carried out by a licensed organization, everyone knows this. Yes, but modern electronics have so simplified the construction of automatic security systems (AOS), while at the same time increasing their functionality and reliability that, figuratively speaking, well-fed wolves vigilantly guard the grazing herd: professionals have stable income, focusing exclusively on security functions, and citizens, without straining the budget, ensure their safety.

To understand why do-it-yourself security and fire alarms have become quite real, and how to do them correctly, let’s take a brief look at the evolution of AOS, their design in general and components, and the principles of organizing security services for residential premises.

How AOS developed

Before chips and reed switches

Initially, AOCs were built in the form of a chain of opening temperature sensors: spring contacts were soldered with Wood or Rose alloys with a melting point of 70-86 degrees. The chain was forcibly closed by a manual call point with normally closed contacts. All this together formed a loop Ш. When heated, the solder melted, the contacts diverged, the circuit broke, the relay included in it, also with normally closed contacts, was released, its contacts closed and turned on an alarm. By pressing the detector button, it was possible to give an alarm manually.

Such systems at the very least worked as local ones, but for communication with the central control panel they required a long line (LAN), prone to faults and having its own leakage resistance, wire resistance, capacitance and inductance, which could cause both false operation and non-operation due to real danger .

Therefore, on the consoles they began to include rays - loops from the LS - into the diagonal of the electric bridge, and into its opposite diagonal - the balanced circuit of the BC (see figure). The beam was no longer characterized by the resistance of the loop R Ш, but by the total resistance (impedance) of the subscriber Z A. By adjusting the BC, we achieved equality of its impedance Z to the impedance of the subscriber Z A. Under this condition, the potentials in the diagonal of bridge 1-2 turned out to be equal, and the voltage U 1 -2 =0. When the sensor was triggered, U 1-2 >0 occurred, which triggered the alarm.

The AOC bridge circuit made it possible to make an important improvement: They began to turn on a resistor of a strictly defined value R Ш in parallel to the detector. This made it possible to judge the nature of the operation by the value of U 1-2: if R Ш remained in the circuit, then someone pressed the detector button, then U 1-2 will be approximately half the maximum ; This is an "Attention" signal. If the sensor opens, we will see a clear open circuit and a maximum of U 1-2; this is “Anxiety”.

Such a system was not very reliable: the slightest malfunction would give a false alarm, a team would come out, and then the installer, expressing his thoughts on this matter in any form, would go to find and fix it. False alarms reduced the degree of trust in the AOS and from the order to the installer the facility remained open. Moreover, splashes of solder sometimes got between the open contacts, and the sensor, “squeaking,” calmed down again. There were cases when criminals shot at the sensors with an air gun through the window, and when they saw that the squad had left, they knew that they had at least an hour to “do the job.”

The BC also caused a lot of trouble: the drug parameters fluctuated greatly. A worker with an electrical engineering education working on a control panel was greeted by the police and firefighters with open arms, but often soon had to sign a statement “on his own”: the salary was small (it wouldn’t go under knife or bullets), and the hassle was no less than that of opera operators.

In large facilities consisting of many subscribers (department store, post office), the beams from the premises were combined into a local console - a control panel (PKP), which automatically gave an alarm over the telephone line when one of the beams was triggered. This made it possible to reduce the dependence of the BC on the state of the drugs, which were already under the control of the signalmen, but reduced reliability: having competently delved into the control panel, it was possible to disconnect the entire object from the remote control and operate there for your own pleasure.

At the same time, attempts were made to use the parallel connection of sensors with thermobimetallic normally open contacts, shunted by R Ш. In theory, this would allow the value of U 1-2 to judge from a remote control the location of the trigger, which a serial system does not allow. However, the open bimetal turned out to be extremely unreliable: the sensor with oxidized contacts did not announce itself in any way in advance, and then remained silent, like a fish on ice, when the fire was already blazing with all its might.

Reed switches

Sealed magnetically controlled contacts - reed switches - made the first revolution in AOS and OPS. Reed switches can withstand billions of operations without oxidizing the contact surfaces, and the problem of temperature operation was easily solved by using holding magnets made of materials with a Curie point of 70 degrees: when heated, the magnet stopped magnetizing and the contacts opened.

The principle of the reed switch allows it to be switched, which gives a reliable sensor suitable for both serial and parallel fire alarm systems. True, the accuracy of determining the trigger location using analog methods remained low, so parallel analog alarm systems did not become widespread. Nevertheless, it was thanks to reed switches that a fire alarm in the apartment appeared: the reliability and low cost of the sensors ensured the cost of the system, affordable even for the average Soviet consumer.

The first smoke detectors also belong to the “reed switch era,” but they were by no means household ones: smoke detection was ensured by ionization of the gap between the fixed contacts, for which it was illuminated by an ampoule with a radioactive isotope. Alarm installers were afraid of such sensors, in a thick steel case and marked with a radiation hazard sign, as if they were fire, and they were rarely used at particularly important facilities.

At the same time, PKPs also began to transform: the use of medium-integrated microcircuits and analog-to-digital converters (ADCs) made it possible to simplify the BC or completely abandon them and measure the beam parameters directly. The first wireless control panels with autonomous power supply also appeared, which, regardless of telephone lines, gave an alarm to the remote control using the Altai system - the prototype of the modern mobile communications, invented in the USSR back in the 50s.

Chips and lasers

A real revolution in OPS was made and made publicly available by large integrated circuits (LSIs, chips) and miniature semiconductor lasers. This affected all links of the OPS, and in new system The best of previous achievements fit in organically (see the picture earlier in the text below).

Sensors using laser detectors monitor temperature and smoke in several parameters at once, which eliminates false alarms (see figure on the left). Some sensors combine the functions of motion detectors; they will be discussed below. “Smart” sensors can also be autonomous, equipped with a built-in battery.

The control panel of our days is a computerized device that can work both with “smart” junior colleagues and with old, but absolutely fail-safe and very cheap reed switches. This made it possible to include SPU in the household fire alarm systems - a signal and triggering device, which, based on a signal from the control panel or directly from the sensor, includes indicator boards, flashing lights, sirens and opens valves automatic system fire extinguishing

Modern OPS are digital-analog parallel-addressed: each sensor is programmed with it email address, and the control panel knows exactly where everything happened. Using advanced software, analog sensors are also quite accurately controlled by loop parameters. The alarm signal is sent via GSM to mobile phone owner and to the computer of the security organization. The alarm can be duplicated directly from the chip sensor, and the activation of the control system can also be triggered from the gearbox.

Motion sensors on the same chips and infrared lasers have made the alarm systems truly security: they control the entire volume of the room or the area of ​​the yard. The laser scanner signal is converted into a code, and the control panel processor continuously compares the codes one after another, filtering out interference from weather, precipitation, and small safe objects.

The capabilities of a modern fully functional security system are presented in the figure. This one is quite expensive, but the system is simpler, quite reliable for an apartment, and you can assemble it yourself. How will be described below, but for now let’s see what is needed and what can be achieved in general:

1. An uninterruptible power supply (UPS) is necessary for the alarm system to continue to operate in a de-energized apartment;
2. Universal sensor-announcers: on the left is a group of autonomous ones, for example. in the garage;
3. Motion sensors;
4. Electronic lock;
5. Reed anti-burglary contactor;
6. Sign board;
7. Local alarm;
8. Display with control panel;
9. Automatic OPS.

Let's give some explanations. Firstly, reed tamper sensors are still in their place, not competing with motion sensors, and the point is not only in cheapness and reliability. The small reed contactor is easy to hide; its operation is not detected by the anti-scanner. The search for such a “bug” (and it is unknown whether it exists at all) with skillful installation requires so much time that hacking loses its meaning.

Secondly, instead of any of the devices in pos. 7, 8 can be connected to SPU. Thirdly, according to item 10: the alarm system must be powered from a separate circuit breaker turned on BEFORE the apartment one, otherwise reliable operation of the system is not guaranteed. And finally, a remote control with an access code display allows you to independently reset, test and reconfigure the alarm system.

Organizational structure

A radical improvement in the technical base also entailed improvements organizational structure OPS: subscribers rarely connect to the EMERCOM console; it is expensive and overloads both equipment and personnel. The role of signal concentrator was taken over by private security firms. It does not light up or is stolen everywhere and not always, and with an acceptable load they can gain a lot of subscribers, which provides a decent income for a small monthly fee.

This system is also beneficial for the owners: a private licensed security guard will be happy to advise, help with advice, and he has no experience in interacting with the Ministry of Emergency Situations and the police. And since the owner still pays him with his hard-earned money, it is easier to demand it if something happens than from a government agency.

Let's take care of the alarm

Do you need a project?

A fire alarm project is needed, and not so much for formal reasons. Only a security guard with extensive experience will be able to accurately indicate the location of devices, their types and connection diagram. Otherwise, the flame may rage beyond repair, and the attacker, immediately spotting the “homemade” (they are well versed in alarms), will only grunt and, having “bombed the hut,” will sit at ease in the owner’s favorite chair, drinking the owner’s cognac, smoking the owner’s cigar, gently stroking the bag on her knees, tightly stuffed with the owner's goods and looking ironically at the sensors in full combat readiness.

However, security companies, generally rightly believing that the main thing is real security, not paperwork, often make concessions to potential subscribers: they agree to do a cheaper project, a sketch, or limit themselves to an even cheaper consultation: where to put what sensors, where to place the alarm control panel, what cable and how to connect everything.

Then, after checking the work, they put him under guard, and based on the documents, they pass him by retroactively. The owner is no worse off for this: once the contract is signed and the apartment is already under control, the security guards bear all the responsibility. The components of a modern fire alarm system are completely reliable; fire alarm maintenance is reduced to: periodic inspection its performance and readiness, which, together with the security company on duty, can be carried out by the owner himself, so, as a rule, there are no problems with service.

How to do what?

The law does not prohibit you from making an OPS yourself, but they won’t take one on the remote control. We will have to limit ourselves to displaying an alarm on a mobile phone, but this is already a serious help in misfortune: the Ministry of Emergency Situations and the police are obliged to respond to any signals from citizens. Therefore, we will describe which equipment to choose for which case, and how to correctly assemble it into a workable whole.

PKP

The types of modern control panels are shown in the figure. The first one on the left is a professional multi-beam analog-to-digital one. These can work with any security system schemes, connect in cascade, ensuring the protection of objects of any degree of complexity and conduct a dialogue with the computer of the security organization, recording and transmitting a complete picture of the development of the situation. They are not used in everyday life.

The next one is semi-professional, digital for parallel address fire alarm systems. It is shown open because From the outside it is a blank box. At the bottom right there is an individual entrepreneur; Next to it is a battery, quite powerful, apparently, for several hours, up to a day, autonomous operation.

At the top left is an electronic unit, and in an empty space next to it in 24-hour guarded premises there is a control panel, but it is usually placed further away. The fact is that the heart of the security system, although equipped with a self-defense system, is still the most vulnerable point of the security system. The work of the processor can be detected by a special scanner, similar to what car thieves do, and interfered with in a manner undesirable for the owner.

Therefore, the control panel is strongly recommended to be placed in a hidden, hard-to-reach and fairly well electrically shielded place, say, in a reinforced concrete basement. As for the RS482 serial interface, which connects the control panel and the remote control, its signals are very well encoded, and it is impossible to get through it to the processor.

Semi-professional PCP in everyday life is used in elite estates individually or collectively in residential complexes: one such control panel allows you to connect up to 255 sensors to it.

The next one is a multi-beam household control panel. This is a device that is already affordable for the average citizen. This device is intended for private households with outbuildings: in addition to servicing reed switches and chip wire beams, it can process signals from 2-8, depending on the model, wireless sensors.

The one on the far right is the simplest apartment control panel. The cheapest models serve only one beam (you don’t need more in an apartment), but, like all of the above, they can transmit a signal to a mobile number. The number in inexpensive household control panels without access using a code from your own remote control is updated upon purchase or from a security company, so you need to keep the phone with it charged and with a valid account: mobile operators charge a fee for receiving messages via GSM.

Household alarm control panels are necessarily equipped with detailed instructions with typical fire alarm circuit diagrams, a list of types and models of sensors compatible with the device, and recommendations for installing the system. Often the kit includes a flashing beacon for the front door and a “Protected object” sticker. These are very useful additions: their presence most often forces villains and vandals to go away.

The control panel must comply with the European standard EN54, which is ensured by SSPB, LPCB or VdS certificates.

Sensors

Sensors and their connecting wires are the key component of the alarm system, which determines its reliability as a whole. First of all, about the wires. Sensors are no longer connected using telephone “noodles”, fragile and unreliable: on sale there are many types of signal two- and multi-core cables in a round outer sheath, which can be laid along the walls so as not to be conspicuous, and hidden under decorative sheathing. But we should talk in more detail about the sensors themselves.

Choice

For an apartment, the best option is the good old reed caps, see fig. For the kitchen, it is desirable to have a chip one that reacts, in addition to heat, to smoke. If significant valuables are stored in the apartment, then it is better to install fully functional ones with motion detectors near their locations.

In a private house, a motion sensor in the yard with a built-in control system loaded onto a lighting lantern would be useful. And it will scare away uninvited guests, and you won’t have to stumble in the dark: the SPU will illuminate it.

Multifunctional sensors are necessarily equipped with an indicator LED, while the simplest ones can be with or without it. The first is preferable: the glow or, conversely, the extinguishing of the indicator indicates a malfunction of the sensor. If there is a false alarm, there is no need to climb the ceiling with the tester - the bad sensor is immediately visible.

Accommodation

At first glance, the standards for placing OPS sensors are very liberal, see Fig.: no further than 4.5 m from a wall or corner and no more than 9 m between sensors. But this was done only for the convenience of configuring a specific OPS, but in fact the placement of sensors is a delicate matter.

Firstly, when placing them on walls, there must be at least 0.2 m to the ceiling, otherwise the sensor may end up in a smoke pocket and give a false alarm. Have you seen smoky rooms? The upper corners are the most smoky there. Secondly, with beams on the ceiling, the sensors need to be placed on their lower surfaces, and not on the sides or in the space between the beams, for the same reason.

And finally, the sensor does not survey the entire hemisphere, and its sensitivity depends on the distance to the source of danger. The controlled area in the form of a circle in an empty room depends on the ceiling height as follows:

• Up to 3.5 m – up to 85 sq. m.
• 3.5-6 m – up to 70 sq. m.
• 6-10 m – up to 65 sq. m.
• From 10 m – up to 55 sq. m.

By flame:

• Up to 3.5 m – up to 25 sq. m.
• 3.5-6 m – up to 20 sq. m.
• 6-9 m – up to 15 sq. m.
• Over 9 m – uncontrolled; the fire will become a fire before the detector is triggered.

“Before” in front of the area means that this is the maximum achievable value - in empty room with proportions in terms of 3/4. Accurate calculation of the location of sensors in habitable rooms requires computer modeling or the eye of an experienced specialist. If the alarm system is done independently without output to the security console, then we can assume that one sensor in the living room “sees” below a square with side L equal to the ceiling height of up to 4 m. The outermost sensors should be placed at half this distance from the nearest wall, and the intermediate ones – at a distance L from each other. In long and narrow rooms are based primarily on the distance between the sensors.

Example: corridor in Khrushchev 1.75x4 m; ceiling height - 2.5 m. Two sensors are needed, located at 1.75/2 = 0.875 from end walls. In the bedroom of the same Khrushchev building 2.5x4.5 m, two sensors are also needed 1.25 m from the end walls.

Connection

Fire alarm sensors are connected strictly according to their instructions. The beam loop always ends with a termination resistor R. Its value is indicated in the instructions for the control panel. Default R=470 ohms, but ratings of 680 ohms or 910 ohms may be required. Let us explain in more detail only two frequently requested points.

First– inclusion of five-terminal IP-212 sensors, which have proven themselves, in a two-wire loop. How to do this is shown in the figure on the left.

Second– connection of conventional sensors with one terminal block. The cable wires must enter/exit the terminal block in a MIRROR way, as shown in Fig. on right.

Third– sensors with two terminal blocks. The left block is for the CABLE, which is connected according to the instructions or as described. But the right one should be dealt with before purchasing: it is intended for autonomous activation of the SPU; Some of the most common circuits of such sensors are shown in the last figure.

If the contacts of the loop (terminals 1-4) and the SPU (terminals 6-8) are electrically separated, as in the rightmost position, then you need to find out the permissible voltage and current or power of the SPU. If the contact is common, as in the other three positions, then the voltage is 12 V at a current of up to 200 mA, and it will go to the SPU from the loop, i.e. load the sensor with light bulbs, bells, etc. you can’t - the control panel will fail.