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Basic types of alarm detectors - operating principles, assembly, configuration

suworow 8172 8
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  • #1
    Admin of Property security
    In this guide we will discuss some basic types of detectors.
    Information on how to connect the detector to the control panel can be found in this guide:
    Connecting any detector to any control panel - guide


    Basic types of alarm detectors - operating principles, assembly, configuration
    PIR motion detector
    (Passive Infra Red) is a passive infrared detector. Detection in it is caused by a pyroelement that reacts to changes in the radiation reaching it. It boils down to the detector reacting to objects moving in its detection field with a different temperature than the ambient temperature. Most detectors are equipped with wide-angle optics (around 90 ) and their effective range is within 10-15 m.

    Infrared detectors are most often found in wall cases adapted for flat mounting or in a corner. For most detectors you can also buy or have special mounting brackets. Detectors adapted for ceiling mounting with 360 field of view are also available on the market. This is e.g. the Satel Aqua Ring detector.
    The PIR detector is most effective when detecting objects moving perpendicular to its "beams".

    Dual motion detectors PIR and MW
    Dual PIR (Passive Infra Red) + MW (Micro Wave) detectors are actually PIR detectors with a microwave sensor using electromagnetic waves, i.e. the Doppler effect. The sensor is equipped with a transmitter and a receiver. Sent waves of appropriate frequency are received by the receiver. In the case of reflection of waves from a moving object, there is a change in frequency, which is recognized as an alarm criterion. I explain to customers that the "microwave" checks if "something" that "PIR" has "body" or whether it was just a breeze. Dual detectors due to the use of a double alarm criterion are much more resistant to false alarms than PIR detectors. Most often they are used in rooms where we can expect air movement. In practice, they are e.g. garages, rooms with air-conditioning, fireplaces, halls, etc. There are also detectors on the market where you can choose OR logic next to AND logic. In practice, due to the too high risk of false alarms, this logic is used very rarely.

    Microwave detectors can interfere with each other, therefore they should not be mounted in close proximity to each other.
    Similar to PIR detectors, dual detectors are most often found in wall casings, often equipped with a suitable holder, and ceiling detectors with an omnidirectional lens.

    Detectors with anti-masking function
    Both PIR and PIR + MW motion detectors can be equipped with a system that detects its masking. If the detector is covered, it signals it at the additional output. In Satellite detectors this is the output described as WRN and e.g. in the Vidicon IX AM detector as R-AM .
    Such detectors should be used everywhere (at least in selected places) where there is a risk of intentional or accidental blocking.

    Detectors with approach zone protection
    A standard detector with Fresnel optics only detects movement from a distance. She does not "see" what moves directly with her.
    Basic types of alarm detectors - operating principles, assembly, configuration

    Sometimes, however, there is a need for the detector to "see" the movement directly below it or in its immediate vicinity (e.g. a detector placed very close to the entrance door to the building just above the keypad, to detect people trying to use this keypad). We can use detectors with Fresnel optics with an additional lens at the bottom of the detector, or detectors with so-called mirror optics.

    The detector detection field seen from the side looks like this:
    Basic types of alarm detectors - operating principles, assembly, configuration

    Examples of detectors with an approach zone implemented by an additional lens:
    Examples of detectors with mirror optics:
    Satel Ivory.

    Curtain detectors
    They differ from ordinary wide-angle motion detectors in reality with a lens. There are also detectors sold as standard on the market with a wide-angle lens, in which the lens can be replaced with a curtain. An example here is the VB curtain lens for Satel Aqua detectors.
    There are also detectors on the market designed from the beginning to the end, including miniature ones to protect e.g. individual window recesses or doors. An example of such a detector can be, for example, the Paradox DG460 Paradoor.

    For example, the detection field of the Satel Agate curtain detector:
    Basic types of alarm detectors - operating principles, assembly, configuration

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    Also read:
    Which GSM transmitter to work with the control panel? + Configuration examples.

    We invite you to familiarize yourself with other guides, featured topics, articles on security systems such as intercoms, gate and barrier automation, alarm systems, cameras, access control:
    Guides on security systems

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    Security Systems

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  • #2
    Admin of Property security

    Basic types of alarm detectors - operating principles, assembly, configuration
    In total, they are ordinary PIR and PIR + MW detectors. I decided to devote a separate chapter to them because of their myths around their way of working.
    You can, for example, come across opinions that the detector recognizes the size / weight of an object, or measures its temperature (the dog has a slightly higher temperature than a human) It's not the fault that the producers themselves give the "immunity" to animals in kilograms. Yes, as in every myth and here is a bit of truth, but this resistance is not really that.
    When deciding to install such detectors, you must know that the more resistant they are to animals, the more resistant they are to people. The simplest animal-resistant detectors simply have an obscured lower part of the lens so that they do not detect something that moves near the floor and are additionally simply "blunt". It is not much better in more expensive detectors, where some algorithms are also tried to be used. While in the case of small, quite calm animals such detectors work, the larger the animal and the more mobile (e.g. cat), the reconciliation of resistance to animals with a high level of detection is less real.
    People who want to leave animals at home and arm the alarm system should be interested in perimeter alarm systems, whose elements are opening (reed), inertial detectors, glass breaks, slat barriers, etc.

    A handful of our forum colleagues' opinions on animal-resistant detectors:

    kood wrote:
    You can set up detectors that will not respond to a dog which weighs 40kg, but there is a high risk that the thief will not detect it either.

    MariuszX49 wrote:
    I tested on my "private" golden retriver and unfortunately, but the following list of sensors did not work (dog equivalent Labrador weighing 40kg at this moment about 50cm in height):
    DSC LC100PI
    DSC LC104
    Vidicon Bingo
    Bosch BPR-WP12

    Also I will be happy to buy a sensor that will work :)

    MariuszX49 wrote:
    @suworow Is a colleague right I just turn on the light with them and everyone spent on the wall after half a year and I know that they "fire up" after passing my fafik and at work it is known either the client will convince himself to another solution, or the client calls another "professional" who finds sensors that meet the expectations of the investor and any intruder ;)

    MariuszX49 wrote:
    So with the correct setting of the above sensors (I was looking for one that responds well to a person and ignores the dog as I wrote to turn on the light) you can't get resistance to animals of the given weight by turning DSC as it did not violate the dog, it happened that he did not react to the household members either.

    taken from the topic:
    Choosing a detector for a large dog

    jacek tecnocom wrote:
    Pay attention to the detector mounting height, the question whether you already have cables pulled or are you just going to do it. For PET detectors, manufacturers provide the mounting height so that it fulfills its function. The next question is whether the dog is lively :-) because with such a mass jump on the so-called a sofa, armchair etc. can trigger an alarm. The detector with PET function does not distinguish whether it is a dog, a cat or maybe a man crawling on the floor. These detectors react less well at altitudes from the floor up to several dozen centimeters. A fake are certainly given in the catalog sheets so. algorithms that prevent the detector from seeing animals.

    taken from the topic:
    PET detectors for alarm systems

    sosarek wrote:
    Well, there will be a problem, because if PET sensors cope with dogs, then with cats not anymore

    taken from the topic:
    Alarm set + CCTV IP - components

    suworow wrote:
    Szyba20 wrote:
    And how is the matter with cats, dogs and other pets, can it be set so that they don't trigger the alarm?
    the resistance to animals of a given sensor depends largely on the size of our pet, his temperament and the extent to which we will be able to meet the requirements contained in the instructions. - read the instructions of any sensor with resistance to animals. The ideal is an empty room with no elements that our pet could enter. Of course, you can adjust the sensitivity of the sensor itself as well as create various logical functions on the control panel but as Bhtom wrote:
    bhtom wrote:
    the more resistant to animals, the more "blunt" to humans.

    For animals and especially cats, perimeter system

    taken from the topic:
    Expansion of the Satel CA-10 alarm
  • #3
    Admin of Property security
    CONTACT OPEN DETECTORS (commonly called reed switches)

    Basic types of alarm detectors - operating principles, assembly, configuration
    Principle of operation The sensor consists of parts with a reed switch and parts with a magnet. In the neutral position, the reed switch remains closed due to the magnetic field forces of the mating magnet. In the case when the cooperating magnet is distant from the contact part, the influence of the magnetic field on the reed switch disappears, causing the reed switch to change position from closed to open. An open reed switch activates the assigned alarm signaling.

    Assembly In the case of wired reed switches we mount in the frame and the magnet in the sash. We try to install as far as possible on the opposite side of the hinges, so that the minimal opening of the window will trigger the alarm. The question is whether to mount the top of the window or the bottom. It depends what effect we want to achieve. If we want the windows to remain ajar when the alarm system is armed, then clearly below. If, for example, you want to control the condition of the windows when arming, if any of them are left ajar, then at the top. You can also mount two reed switches, one on top and one on the bottom :)

    Connection to the control panel
    Although reed sensors usually do not have a tamper contact (except in a few cases such as reed sensors with tamper loop and e.g. Alarmtech MC 470) they can also be connected to the control panel in DEOL (2EOL) and what is more, it can even be connected to one zones of several detectors (this is not recommended, but sometimes used within the same room or window) Ropam, three reed switches Satel S-4 in series
    Reed detectors with built-in resistors in DEOL configuration are also on sale. An example here may be a sensor from the Satel K2 2E company equipped with 1.1k resistors, i.e. adapted to the parameterization used in Satel exchanges, but also by Ropam or Genevo.

    Due to the method of assembly and application, we can distinguish:

    o recessed, eg Satel B-2 or B-2T
    Basic types of alarm detectors - operating principles, assembly, configuration Basic types of alarm detectors - operating principles, assembly, configuration

    o surface with a cable, eg Satel K-1
    Basic types of alarm detectors - operating principles, assembly, configuration

    o surfacing with a screw connection, eg HO-03
    Basic types of alarm detectors - operating principles, assembly, configuration

    o recessed into metal frames with a flange, eg HO-03L
    Basic types of alarm detectors - operating principles, assembly, configuration Basic types of alarm detectors - operating principles, assembly, configuration

    o special in aluminum housing for outside use, for entry gates, gates etc. eg HO-03FN, HO-03FP, HO-03I
    Basic types of alarm detectors - operating principles, assembly, configuration Basic types of alarm detectors - operating principles, assembly, configuration Basic types of alarm detectors - operating principles, assembly, configuration

    Reed sensors with increased security level detecting attempts to apply a foreign magnetic field . An example of this could be, for example, the Alarmtech MC 370 or MC 470 detector. If you are interested, please refer to the detector's instruction manual available at our forum, where everything is very well explained. Similar functionality offered by the MC 370 or MC 470 detectors, but not exactly the same, can be achieved by using two ordinary reed switch detectors side by side: Reed switches - 2EOL + foreign field detection

    I encourage everyone who intends to mount opening sensors to read these topics.
    You will learn from them what to do, how to do it and how not to do it.

    Is it worth to install reed switches, how to install them correctly, examples of correct and incorrect assembly. Factory-fitted or by the alarm system installer? In this topic I recommend especially the statements of a colleague @_ZBYCH_
    Reed switches in the windows - request for an opinion

    Installation of reed switches is not very successful. How to improve it:
    Reed contacts installed badly

    About the fact that tamper loop is something different, and protection against applying a foreign magnet is another thing. Several reed switches on one control panel line:
    Installation of reed switches in the plastic window profile - a new question

    Reed sensors, foreign magnet detection:
    Reed switches - 2EOL + foreign field detection
  • #4
    Admin of Property security

    Basic types of alarm detectors - operating principles, assembly, configuration
    Their task is to detect vibrations accompanying the attempt to break the window or door or breaking the wall.
    Most often they complement reed switches in perimeter systems.

    Good inertial detectors can react to:
    o momentary shock waves with high amplitude
    o Medium energy attacks by counting the number of pulses
    o events of long duration (drilling, cutting, etc.)

    The most popular models are:
    Satel VD-1, Texecom Impaq Plus, Risco ShockTec RK600S, Optex Vibro, Alarmtech CD 550.

    Some inertial detectors may be additionally equipped with a reed switch opening sensor. They are e.g.
    o Satel VD-1 detector available only in this version. Violation of the detector detecting vibrations and the detector detecting opening (reed switch) is signaled on the same alarm contacts. In the case of this detector, it is impossible to distinguish what caused the alarm, opening or blow.
    Basic types of alarm detectors - operating principles, assembly, configuration

    o Texacom Impaq Plus MC detector. Here, the violation of the reed switch detector is signaled on separate contacts than the shock detector violation. So we can connect both signals to the control panel separately and have information about what caused the alarm. Of course, the installer can also sum up both signals on one line using e.g. the scheme of connecting two detectors on one line in DEOL.
    o Risco ShockTec Plus. Like the Impaq Plus MC detector, it has additional contacts for signaling from a reed switch detector.

    We try to install the detector as close as possible to the place of expected shocks, i.e. at the bottom of the window. When choosing the place of its installation, one should also consider whether it fits e.g. between the window sill and the sash or between the wings, and the fact that in such rooms as e.g. bathrooms on the window steam may collect and run down it to the detector. The detector range often indicates the detector range. These data should be treated as approximate. In fact, the range of the detector will depend on the properties of the material on which the detector is mounted, on how this material transmits vibrations.

    Which sensor to choose, where to mount and whether to mount on a given type of substrate (most often a window or door). Whether to use reed switches built into the detectors or install separate recessed ones, for example.
    There is no definite answer. To properly choose to install and then adjust such a detector, you just need some experience.
    In the case of detectors with a built-in opening detector, it is worth carrying out several tests before puncturing the windows. Built-in reed switches, e.g. in the VD-1 detector, can surprise you with their action :)
  • #5
    Admin of Property security

    Basic types of alarm detectors - operating principles, assembly, configuration
    Most often they are PIR or PIR + MW detectors operating on the same principle as internal detectors. And like them, they can be wide-angle, curtain, anti-masking detectors, etc.
    We often read in the datasheets of these devices that in order to maintain a high level of detection and at the same time minimize their susceptibility to false alarms, they used a whole range of technologies. It is difficult to discuss it, but it is impossible not to notice that it is incompatible, as in the case of internal sensors resistant to animals, both of these things, that something must be done at the expense of something.

    o protection of the approach area to the facilities
    o protection of garden equipment
    o protection of storage yards

    Our forum colleagues commented on the subject of external detectors. Let me quote a few words:

    _ZBYCH_ wrote:
    Experience, perseverance and imagination are needed for all external detectors ;)
    WatchOut assembly at 4m height = no understanding of how it works :|
    Belief in marketing descriptions about detector resistance to animals up to 70 kg = faith in miracles ;)

    _ZBYCH_ wrote:
    Many problems with the functioning of external detectors are associated (except for the lack of experience of the installer) with a lack of understanding of the laws of physics and non-compliance with installation instructions.
    I see a lot of objects with incorrectly mounted external detectors. Usually, this applies to the detector mounting height or inclination, as well as the detector's direction, e.g. towards the street.
    Even if it is a dual detector in which the infrared path range can be set or masked, the microwave path always has a certain shape. If the detector is improperly installed, the microwave path is often violated and all you need is a "little thing" to activate the infrared path and activate the alarm.
    The detector installed too high does not work at all as intended by the detector designer, and the detector's inclination only makes the situation worse.

    Reading some posts I conclude that often people buying external detectors blindly believe the assurances of the manufacturer.
    They misread (or interpret) the manufacturer's assurances, e.g. regarding the detector's resistance to animals. Reading in the leaflet about detector resistance to animals up to 20, 40 or ... 70 kg, they consider that the kitty weighs about 5 kg, the bird is negligible, because it weighs max 2 kg, and his dog weighs only 18 kg, so the detector is perfect and can handle ...

    To understand how the detector is able to ignore animals, it is necessary to become acquainted in detail with the way of operation of individual detector paths (infrared and microwave).

    The same goes for anti-masking.
    You also need to understand the principle of anti-masking based on the infrared or microwave path (we return to physics ...).

    To sum up - sometimes people choose a given product, wishing it will work according to their ideas and expectations, not the laws of physics and the assumptions of the designer ...

    nikspol wrote:
    And it is impossible to disagree with what ZBYCH wrote - you need experience and perseverance as well as imagination to properly "mount" them. And everything that is written in the instructions applies only to "clean" and level ground, and how it looks in practice - we know.

    quotes from the topic: Risco WatchOut - Replacement

    luk9753 wrote:
    Exactly, there is no perfect solution, as if the algorithm of recognizing the intruder in the external sensor was like in a normal "home" sensor, it would result in constant excitations,

    quote taken from: Rokonet Watchout - tests

    I will add an example from myself

    In the watchout detector catalog card we can read that it uses rocking recognition technology:

    The rocking recognition technology extracts swaying objects such as bushes, trees or signs, e.g. traffic signs. The rocking recognition technology is possible due to the use of two microwave channels, which distinguish impulses from a moving object and allow you to accurately determine the distance from the sensor and which direction the object is moving. Rocking objects that do not move more than a certain distance are ignored.

    In the manual itself we will read:
    Avoid pointing the detector towards moving objects (swaying branches of trees, bushes, etc.)

    Is it worth using such detectors?

    In my opinion, yes, but not at the expense of the internal or peripheral system. A well-installed system may turn out to be unbreakable by let's call it "ordinary thief" and even for a more experienced amateur of our property it may prove to be a hindrance. It will be our first line of defense.
    There is one basic condition here. Such a system must be least susceptible to false alarms. A system in which false alarms occur all too often will simply become a nuisance to our neighbors and ourselves. We'll stop taking his alarms seriously, and finally stop switching it on. With an external system, it is worth trying video monitoring, which will help us determine the cause of the alarm.

    What to do to prevent this happening, what to consider so that the system actually fulfills its task?

    o Arrangement of elements of small architecture, equipment.
    o Plan of the garden, ponds, vegetation, etc.
    o Distances to the fence and its type (the height of the fence, whether it is full, e.g. densely minted or openwork
    o Sunlight
    o The detectors should be carefully adjusted, while remembering that their range may depend on the size / weight of the moving object and the ambient temperature. The detector can ignore outside the detection field of interest, e.g. one man's passage, work when a group of people pass or a car passes.
    o Select the detectors accordingly. No one said that under one system several types may not be used.
    o Observe the installation height and conditions. What we can get away with quite dry in the case of ordinary internal motion detectors in the case of external can simply end in disaster.
  • #6
    Admin of Property security

    Basic types of alarm detectors - operating principles, assembly, configuration
    The detection is based on the analysis of sounds accompanying the glass beating, and the algorithms used are designed to ignore sounds coming from another source, which is to prevent false alarms. The premise is simple. We install reed detectors in the opening windows, the glass break detector on the wall and the whole room is protected, and the intruder is detected before it even enters it.

    And how is it in practice? In my opinion, this is in itself one of the better solutions, but under certain conditions:

    o First of all, you need to be aware that it is one of those detectors that, if incorrectly calibrated, can become the source of a series of false alarms or simply do not work when it is needed. Leaving such a detector on factory settings is not a good idea.
    o A special tester is needed for calibration, which rather a person who does not perform alarm systems on a daily basis will not have in stock.
    o Because the sensitivity of the device depends on the acoustics of the room itself, the calibration should be done in the furnished room and repeated after each significant change in the interior arrangement. The only question is who will remember it, or what will happen when a room usually empty one day becomes a warehouse full of boxes.

    Persons interested in such detectors are referred to the Polish manufacturer's website, where you can watch e.g. a film showing how to properly calibrate such detectors. https://alarmtechglobal.com/pl/akustyczne-detektory-zbicia-szyby/15-ad-700.html
  • #7
    Admin of Property security

    Basic types of alarm detectors - operating principles, assembly, configuration
    Used to protect individual window or door openings, or entire window and door lines. They can be used both indoors and outdoors.

    Principle of operation

    A slat barrier is nothing more than a series of photocells (such as those found in elevators or gates) placed close to each other. So we have a strip with transmitters and a strip with receivers. Interruption (entry into the light) of one or two beams causes the alarm criterion.

    The undoubted advantages of this solution are:
    o Early detection of an intruder at the stage of attempting to break into the object.
    o Freedom to use the rooms. We can open or tilt the windows without fear that we will trigger the alarm, even leave them open at night.
    o It is often a great alternative to systems based on external motion detectors. Barriers definitely protect the object better, are much more effective than external detectors, and at the same time less susceptible to false alarms.

    Installation Tips
    o We try to position the receiving strip so that the sun's rays do not fall perpendicular to the optical elements.
    o Before wiring we should check exactly what length and with how many bundles of strips our supplier offers. What is the method of fixing the barrier to the ground? Only then should we make the wiring, making sure to route the cables exactly in the designated places. Lack of precision when laying cabling can definitely hinder the installation of the barrier and affect the aesthetics.
    o Avoid in the field of activity barrier the presence of objects that could violate it, such as branches of trees or shrubs.
  • #8
    Admin of Property security

    Basic types of alarm detectors - operating principles, assembly, configuration

    Smoke detectors
    Optical detectors are usually used in alarm systems. Whether they work and whether they will not generate false alarms depends largely on whether we place them correctly. According to the recommendations, it is best to place them on the ceiling at a distance of min. 30 cm from the wall. To avoid soiling the sensor chamber and thus generating false alarms, do not place them directly above fireplaces or e.g. kitchens. Some smoke detectors are additionally equipped with temperature detectors.

    Rock detectors
    We try to place near the source of its possible formation, i.e. near fireplaces, stoves, etc. The recommended mounting height for such detectors is about 1.5 m from the floor.

    Gas detectors
    Here it should be remembered that other detectors react to natural gas and others to propane-butane and cannot be used interchangeably. Due to the way these gases are spread, these detectors are also mounted at other heights. Detectors of natural gas, which is a light gas - in the upper part of the rooms, and detectors of propane-butane, which is a gas heavier than air - low at the floor.

    Flood / water detectors
    We install wherever there is a risk of flooding. The cable to the detector itself is lead out of the wall e.g. at a height of several dozen centimeters, and we descend to the floor with a probe. To limit damage caused by flooding, a water shut-off valve may be attached to the alarm system.

    Sleeping gas detectors
    We install them at the height of the bed, in the place from which we expect the inflow of such gas (e.g. around the window).

    Opinions about whether it is worth using them are so divided that I can refer you to a rather interesting discussion that once took place in the forum:
    No installer question - sleep gas sensor

    Persons interested in the assembly of the above detectors refer to these topics:
    Smoke and carbon monoxide detectors - how to arrange them to be effective?
    Flood, smoke and carbon monoxide detectors - do they need to be deployed to make them effective?

    It is also worth looking at the instructions for such detectors before wiring:
    Alarm instructions for smoke, gas and flood detectors

    All these detectors are connected to the alarm system in the same way as e.g. motion detectors. We set the type of reaction for them for 24h, so that they trigger an alarm regardless of whether the system is armed (armed) or not.