Burglar and Fire Alarm
Hello harachelovek. When you were in a comfortable office or any other place of work, you probably paid attention to all these incomprehensible things on doors, walls, windows and ceilings. So, these things help to preserve your property, values and even life.
Today I will try to tell how these things are arranged, why they are needed and how it all works. Sometimes it’s just not superfluous to know about the nature of things that surround you. Under a
A few words about the alarm
The alarm system is autonomous and remote. Autonomous alarms are not displayed anywhere, maintenance and control is carried out by the owner, authorized person or working personnel of the protected facility. The console security is connected to the central monitoring console of the on-duty personnel of private security, the fire service or a non-state private security company (PSC), usually via a telephone exchange or a radio channel.
The security alarm system has 3 security lines, in which sensors of their type are used.
- 1st line - The perimeter of the guarded object (windows, doors, walls)
- 2nd line - Indoor facilities (apartments, offices, garages)
- 3rd line - Indoor objects (safes, paintings and other valuables)
- Thermal
- Smoke
- Hand held
Alarm control panels
Alarm systems are controlled by control panels (PKP), in which case they include sirens, voice alerts, and also “call” the police and firefighters. These devices monitor the status of their alarm loops (ALs), which can be many. Security or fire detectors (detectors) are connected in loops, which can also be more than a dozen. If triggered, the sensors can (depending on the type of sensor and how it is connected)short circuit or open loop. Usually, a terminal element (OE) is connected at the end of the loop, the role of which can be played by a diode, a capacitor, and in most cases, as a rule, a resistor of a certain rating is a protection against possible malfunctions of sensors and incompetent crackers who try to close the loop. Increasingly, in modern devices, the terminal element is informative in order to report various problems in the loop.
It turns out that the control panel makes sure that the cable does not go beyond the set value of the terminal element, otherwise the control panel will “think” that the cable is not working properly and will turn on the corresponding indication or is broken and will go into alarm while manipulating its output.
The control panel outputs can also be different, the main ones are a normal relay, a radio transmitter, an RS-485 interface, and various kinds of signal-triggering devices. The control panel output may even become a loop of another control panel. One control panel can have several types of outputs simultaneously.
A characteristic feature of the device is also its control method.
So, the control panels differ in the number of loops, the OE ratings of these loops, the control method, the number and type of outputs.
Common Detectors
Detectors are designed to register certain events and report them to the control panel. To do this, they are equipped with an output relay, a radio transmitter or RS-485 interface (addressable detectors). Detectors can also be autonomous, i.e. not work with the control panel, but have their own means for light and sound notification in case of operation. Some can be combined and have the properties of several types of detectors simultaneously. Most detectors are protected against tampering; many also require separate power.
QMS
The signaling device is magnetic contact. It consists of two parts - a reed switch and a magnet. Reed switch getting into the action of a magnetic field closes its contacts. It is mainly used on doors and windows, has different designs for suitable operating conditions.
Acoustic detectors
Consist of a microphone and a transducer. Record the sound of breaking glass. To reduce false positives from extraneous sounds - tuned to a specific range of sound frequencies. Many detectors allow you to adjust the sensitivity, are equipped with an indication of events and can store the trigger in memory.
The so-called "volumetric"
Under the "volumetric" is usually understood - motion sensors. The most common are infrared and radio waves.
The principle of operation of infrared sensors is based on recording changes in the thermal background in the sensor coverage per unit time. Therefore, it is not recommended to direct or install them in places with a possible frequent change in temperature (radiators, vents, windows).
In the radio wave detector, the principle of human detection is implemented by detecting the Doppler frequency shift of the reflected microwave (microwave) signal that occurs when a person moves in an electromagnetic field created by the microwave module. Such sensors can be masked by obstacles from materials that transmit radio waves. ( Original and in more detail )
Some volumetric devices allow you to protect rooms with pets inside. Many detectors also allow you to adjust the sensitivity, equipped with an indication of events and can store the trigger in memory. Smoke
detectors
Smoke optical-electronic fire detector. Designed to detect fires, accompanied by the appearance of smoke, in enclosed spaces. The operating principle of the detector is based on recording changes in the optical density of air per unit time, with a threshold value characteristic of smoke. The detector is triggered by the inclusion of a built-in optical indicator (LED).
The trigger can also be dust and small insects that have got inside, so at least twice a year, such detectors require inspection and cleaning.
In case of a false alarm, do not be too lazy to pay attention to the LEDs of such sensors, remember the one in which it was on and indicate it to the maintenance personnel. This will save you from future headaches.
Thermal fire detectors
Record the temperature rise in a room above a threshold value. Old samples were two electrodes fused with low-temperature solder. Modern samples are more reliable and have resistance thermometers or thermo-relays. Each detector is configured for a specific triggering temperature. Some have LED indicators and allow you to visually determine the trigger of a particular detector.
Manual fire detectors.
In case of fire, they are manually activated. Typically installed at the exits.
At first, as soon as they were put into operation in Russia, the detectors were anonymous buttons, and the inquisitive minds of compatriots, and someone just out of hooligan motives, did not give the fire departments peace of mind day or night. A little later, in order to defeat the mentality, detectors were put into operation equipped with detailed information on use directly on the housing, and some were also equipped with a sealing device.
Alarm
I almost forgot. Unlike burglar and fire alarms, an alarm is a little more than fully designed to protect people from their own kind. The most widespread alarm buttons of various types and designs. At first, the cash desks were equipped with buttons, the buttons were located under the tables, sometimes they were special pedals. Then they began to be equipped with points of sale of alcoholic beverages, the guards appeared portable radio remote controls. Then school and preschool institutions - first of all, the events that happened in Beslan influenced it. Now buttons are used everywhere, shops, offices, state. institutions.
And thanks to the alarm you can do interesting things .
Afterword
Films have always been touched, where with the help of inconceivable devices and high technologies, a group of brave guys breaks in safes of federal banks and completely does not noticeably escape the guards with all the good :)
In truth, in reality, most likely, such heroes will have the only attempt, if of course they do not help them indifference of the security company and apathy of the staff. It happens that the employer himself chases the cheapness and as a result gets a crude project with cheap nameless alarm devices, having constant false positives and a bunch of other headaches.