Basic knowledge of anti-theft alarm system

Ask your question such as how to install home security systems, where to place the motion sensor, what type of smoke detector to choose for my case etc. Professional security system technician will answer the questions.
Post Reply
vedard
Posts: 532
Joined: Wed Dec 05, 2018 12:27 am

Basic knowledge of anti-theft alarm system

Post by vedard »

1) What parts of the alarm system consist of?
Answer: A simple alarm system consists of a front-end detector, an intermediate transmission part and an alarm host. Larger systems can also regard the detector and the alarm host as the front-end part, the transmission part from the alarm host to the alarm receiving machine, and the central alarm receiving part as the back-end part.
2) According to different information transmission methods, what types of alarm systems can be divided into?
Answer: According to the different ways of information transmission, there are two types from the detector to the host: wired and wireless. From the host to the central alarm receiving machine can also be divided into two types: wired and wireless. The wired system can also be divided into two types: telephone line-based transmission and bus-based transmission.
3) What is an alarm host?
Answer: Alarm host: the "brain" part of the alarm system, which processes the signal from the detector and controls the alarm system by providing arming and disarming operations through keyboards and other devices. It can provide sound/light prompts when alarming, and can also transmit the alarm information to the alarm center through the telephone line.
4) What are the common types of defense zones in the alarm system?
Answer: Common types include entry and exit zones, real-time zones, internal zones, and 24-hour zones.
5) What is the entry and exit zone?
Answer: Entry and exit zones are also called delayed zones. After arming, the system will provide a certain time delay for entering and exiting the defense zone. After the exit delay time expires, the delay defense zone system alarm will be triggered. When the delay zone is triggered when entering, the controller will beep during the entry delay time as a reminder signal to disarm the system. The system must be disarmed within the set delay time, otherwise it will alarm. This zone type is suitable for the user's entry/exit operation keyboard must pass.
6) What is a real-time defense zone?
Answer: When the real-time defense zone is triggered after the system is armed, it will alarm immediately without delay time.
7) What is an internal zone?
Answer: Internal defense zone: After the system is armed, if the entry and exit zone is triggered first and then the internal defense zone is triggered, the internal defense zone will also enter the delay state and will not immediately alarm. The delay time of the defense zone is the same as the entry and exit zone. If the internal defense zone is triggered before the entry and exit zone is not triggered, the system will immediately alarm.
8) What is the perimeter zone?
Answer: Perimeter defense zones are used for exterior doors and/or windows. When the defense zone is triggered, an alarm will be issued immediately.
9) What is a 24-hour defense zone?
Answer: The 24-hour defense zone is not affected by arming or disarming, and the zone is triggered and immediately alarms.
10) What is a 24-hour audible emergency zone?
Answer: 24-hour audible emergency defense zone: It is a kind of 24-hour defense zone. When this type of defense zone is triggered, external warning lights and siren will give out sound and light prompts, and display an alarm on the keyboard. This type is suitable for emergency buttons.
11) What is a 24-hour silent emergency zone?
Answer: 24-hour audible emergency defense zone: It is a kind of 24-hour defense zone. When this type of defense zone is triggered, the external warning lights and siren will not emit sound and light prompts, nor display alarms on the keyboard. This type is suitable for emergency buttons in important places such as banks and jewelry counters.
12) What is a fire zone?
Answer: Fire zone: a type of 24-hour zone. A fire alarm signal will be issued when the defense zone is triggered, and the keyboard will display the defense zone number and trigger an external siren to sound a special alarm. For use in a 24-hour fortified area equipped with smoke detectors, heat detectors or emergency buttons.
13) What is out of home arm?
Answer: Out of home arm: refers to a mode of arming the system when all users leave the protected area of ​​the alarm system. In this mode, all defense zones in the system are in working state.
14) What is home arm?
Answer: Stay-home arming: refers to a mode of arming the system when the user is in the internal protection area of ​​the alarm system. In this arming mode, all perimeter defense areas in the system (such as outdoor perimeter probes, window magnets, curtains on balcony) Type probe, etc.) is in the armed state, and the internal defense zone in the system (usually an infrared probe installed indoors) will be automatically bypassed by the system, and internal personnel can automatically move in this area without generating an alarm.ome arm.
15) What is disarming?
Answer: Disarming: refers to the alarm host exiting the alert state by password or key method.
16) What is to eliminate the alarm?
Answer: The system has an alarm during the arming period, and there is still a prompt on the keyboard after the defense is disarmed. To eliminate the alarm is to stop the alarm sound after disarming and return to the disarmed state.
17) What is the entry delay?
Answer: Entry delay: It means that the entry and exit of the defense zone is triggered after a person enters the entry and exit zone from the outside, but the system will not immediately alarm, but is in the entry delay state (usually tens of seconds). During this process, you must immediately disarm the alarm system correctly, otherwise the system will generate an alarm after the entry delay expires.
18) What is the outgoing delay?
Answer: Outgoing delay: refers to the delay time (usually several tens of seconds) left for the operator to leave the zone after the system is armed. You must leave the entry and exit zone during this time, otherwise you will trigger the entry and exit zone after the delay expires.
19) What is bypass?
Answer: Bypass: When arming, one or some of the zones will not be added to arming.
20) What is the installer password?
Answer: The password used by the installer, through which you can enter the programming of the system and set up the system.
21) What is the owner password?
Answer: The password used by system operators is the highest level password among all operator passwords. This password can be used to manage the passwords of other users.
22) What is a duress password?
Answer: When the user needs to disarm the system under the threat of hijacking by gangsters, you can use this duress password to operate. At this time, it appears that the system is normally disarmed, but in fact the system will silently send a duress alarm to the center.
23) What is a dual-network alarm host?
Answer: An alarm host with dual communication functions of telephone line alarm and GSM wireless alarm. When the telephone line fails, the information can be automatically transmitted through the GSM communication module, and the two communication methods can also be used at the same time. Greatly improve the reliability of information transmission.
24) What are the advantages and disadvantages of wired/wireless alarm systems?
Answer: The detector of the wired alarm system and the host are connected by a data cable, and the host to the alarm center adopts telephone line or bus transmission mode. The wired alarm system has low cost, high reliability, and convenient maintenance, but it has shortcomings such as long construction period and large engineering volume. It is suitable for places with low requirements for beautiful environment.
25) What are the types of detectors? What are the common types on the market?
Answer: Infrared, microwave, vibration, smoke, air, broken glass, pressure, ultrasonic, etc. Among them, infrared detectors can be divided into active infrared and passive infrared, and smoke detectors can also be divided into ion type and photoelectric type.
Commonly available in the market are infrared detectors (passive infrared), infrared through-beams, infrared fences (active infrared), double-check detectors, vibration detectors, glass break detectors and so on.
26) How does the active infrared detector work?
Answer: Active infrared detector is composed of infrared transmitter and infrared receiver. The infrared transmitter emits one or most modulated infrared rays to the infrared receiver. When there is no obstruction between the transmitter and receiver, the detector will not alarm. When an object is obstructed, the output signal of the receiver changes and the detector alarms.
27) How does the passive infrared detector work?
Answer: There are two key components in a passive infrared detector, one is a Fresnel lens and the other is a pyroelectric sensor. Any object in nature higher than the absolute temperature (-273o) will produce infrared radiation, and the wavelength of infrared energy released by objects at different temperatures is also different. The human body has a constant body temperature, which is different from the ambient temperature. When the human body moves, the change of this difference is detected by the pyroelectric sensor through the Fresnel lens, thereby outputting an alarm signal.
28) The role of Fresnel lens
Answer: The Fresnel lens has two functions. One is to refract or reflect the pyroelectric infrared radiation to the pyroelectric sensor, and the other is to divide the detection area into several bright and dark areas.
29) What is a dual-element infrared detector?
Answer: The detector that integrates two pyroelectric sensors with the same performance and opposite polarity is a dual-element detector.
30) What is a four-element infrared detector?
Answer: The detector that integrates 4 pyroelectric sensors with the same performance and opposite polarity is a quaternary detector.
31) What is temperature compensation?
Answer: In general, the human body temperature is always much higher than the ambient temperature. When the intruder moves, the sensor receives the infrared change signal with a large amplitude and triggers an alarm. When the nearby environment temperature rises to close to the temperature of the human body, the amplitude of the infrared change signal received by the sensor when the intruder moves is very small, so it is possible that the signal will not be alarmed because the signal is less than the trigger threshold.
32) What is analog pulse technology?
Answer: Analog pulse counting: The detector measures the length of time the output signal exceeds the threshold. If the output of the amplifier exceeds the threshold for the length of time that reaches the preset value, an alarm signal will be triggered. The pulse count is generally adjustable from 1 to 3 levels. When the pulse count is 1, the sensitivity of the detector is extremely high. When the pulse count is 3, the sensitivity of the detector is lower but the ability to prevent false alarms is stronger.
33) What is digital pulse technology?
Answer: Digital pulse counting: The detector counts the number of sector trigger edges triggered by the intruder from the beginning through digital counting, and triggers the alarm signal according to the preset digital pulse count.
34) How does the microwave detector work?
Answer: The microwave detector uses the principle of the Doppler effect. In the microwave section, when transmitting at a frequency, when the emitted microwave encounters a fixed object, the frequency of the reflected microwave does not change, that is, f send = f receive, and the detector will not send an alarm signal. When the emitted microwave encounters a moving object, the frequency of the reflected microwave will change, that is, f send ≠ f receive, and the microwave detector will send out an alarm signal.
35) What is Shuangjian detector? What are the common Shuangjian detectors on the market?
Answer: In order to overcome the shortcomings of a single technology detector, two types of detectors with different technical principles are usually integrated together. The detector that only alarms when the sensors of the two types of detection technologies detect the movement of the human body is called a double-check detector. . The most common dual-check detectors on the market are microwave + passive infrared, and infrared + air pressure detectors and audio + air pressure detectors.
36) What is Sanjian detector? What is Sijian detector?
Answer: In order to further improve the performance of the detector, a detector with microprocessor technology added to the dual-check detector is called the three-check detector. Another technology is added to the Sanjian detector to become the Sijian detector.
37) What is a shock detector?
Answer: Vibration detectors are based on the vibration signals generated by detecting intruders performing various sabotage activities. For example, when an intruder conducts sabotage activities such as wall digging, drilling holes, prying safes, etc., these objects will be caused. vibration. Detectors that use these vibration signals to trigger an alarm are called vibration detectors.
38) What kinds of common seismic detectors are there? How does it work?
Answer: According to the different vibration sensors used, vibration detectors can be divided into: mechanical vibration detectors, inertial rod electronic vibration detectors, electric vibration detectors, piezoelectric crystal vibration detectors, electronic comprehensive vibration detectors Detectors and many other types. Recently, the most common piezoelectric crystal vibration detectors are based on the principle of using the piezoelectric effect of the piezoelectric crystal. Piezoelectric crystal is a special crystal, which can convert the mechanical force applied to it into an electrical signal of corresponding size. The frequency and amplitude of the electrical signal are proportional to the frequency and amplitude of the mechanical vibration. When the signal value reaches An alarm signal is issued when the value is set.
39) How does the glass break detector work?
Answer: When the glass is hit and the glass is not broken, an ultra-low frequency elastic vibration wave will be generated. This mechanical vibration wave is lower than 20Hz and belongs to infrasound. The frequency of the loud and harsh sound emitted when the glass is broken is approximately in the range of 10-15KHZ, which is a high-frequency sound. When the detector detects both low and high frequency sound frequencies, it will generate an alarm signal.
40) What is the standard output signal of the detector?
Answer: The standard output signal of the detector is a switch signal, which is available in normally open, normally closed, and normally open/normally closed options.
41) What are the advantages of the detector's alarm memory function?
Answer: If more than one detector is connected to a defense zone, when an alarm event occurs, it is usually impossible to distinguish which detector is alarming. Using the alarm memory lock function of the detector, when an alarm event occurs, after the detector alarms, the alarm indicator will keep flashing until the system is reset. In this way, it is possible to identify which detector is warning.
42) What are the advantages of magnetic shielding relays?
Answer: Magnetic shielding relay can prevent wireless electromagnetic interference and external force interference. If the detector does not have a magnetic shielding relay, when the magnetic substance is close to the detector shell, the external magnetic field can keep the relay normally open, send out a false alarm signal, and then make the detector fail.
43) What are the advantages of a sealed optical system?
Answer: It can prevent small insects from crawling into the lens, and can prevent false alarms caused by air flow in the detector (near the sensor). Prevent bad reflections in the detector. Ensure the accuracy of the focus of the infrared sensor.
44) How to choose suitable infrared beam products for customers?
Answer: Two points should be considered when choosing a target product. One is to choose according to the environment of the perimeter. If the environment is good, you can choose 2 beams. For the worse, you can choose more beams. In addition, choose the warning distance of the beam according to the distance of each straight line segment of the perimeter. The combination of 2 parameters can select the appropriate product. In addition, according to the customer's requirements for appearance, we can choose different shapes of opposite shot products.
45) What should be paid attention to when installing infrared beam?
Answer: The radio should be fixed on the mounting bracket, and the mounting bracket must be firm to avoid shaking. The installation height is generally 30 cm above the warning surface, and there should be no trees, birds or other small animals inside the warning line. Avoid cross-reception when installing multiple sets of infrared beams on the same warning surface. The equipment access point should be sealed and waterproof.
46) How to choose indoor detectors for customers?
Answer: Customers with better environment can choose infrared detectors, and those with poor environment can choose Shuangjian detectors. Then choose products with different detection distances according to the area that customers need to guard against. For places where people are still active after arming, you can choose infrared curtain detectors.
47) What should be paid attention to when installing the infrared detector?
Answer: The front of the detector should not be blocked by objects, avoid moving objects into the detection viewing area, avoid cold and heat sources, avoid locations where small animals often move, and avoid facing the sun or the place where the sun reflects
Shop Focus brand wireless alarm, HB solar power alarm, HST fire alarm at https://www.vedardalarm.com

Post Reply