Basic principles of security alarm design
With any design of the security alarm, everything is guided by certain rules and characteristics of specific sensors, signaling blocks, etc. After all, the ultimate task is to make sure that the probability of detecting unauthorized persons at the facility is maximum.
Let’s look at the main types of sensors:
Movement sensors can be installed at the discretion of specialists in any quantity for the complete exclusion of dead zones. They are standardly installed at a height above human height, under the ceiling, but usually not higher than 2.5 meters. The detection zone of a passive sensor and its variety is selected depending on the protected place (since this is the cheapest and least capricious sensor to external influences, it is placed. If ultrasonic or radio waves are installed, they are guided by the same principles in height). Such sensors with a security zone type “volume” can easily detect movement up to 6 meters (in length from themselves).
Sensors with a detection zone of the type of “curtain” are installed above the doorways at an unattainable height, sent optics down into the passage. In appearance, they are very different from sensors such as “volume” with a much narrower optics strip and more curved so that the viewing angle is almost 180 degrees.
Sensors with a beam type detection zone are rarely used (more often several pieces of type “volume” are placed). It is installed both at high and low height in narrow corridors. In the presence of such a sensor in the corridor, other motion sensors may be absent.
Sensor sensors of the glasses are installed on the slopes on top, but if such an option is impossible, they can be installed either on the ceiling directed by the microphone on the window or on the wall opposite the window, but not further than 6 meters. One sensor is able to cover with its area from 0.1 to 100 square meters of whole glass. It can be installed on the ceiling or wall one for several windows / window.
Doors opening sensors are also called differently – magnetically contact sensors are usually placed on the front doors and gates, and special sensors are placed for the gate with a rfonal of the rowing of a rugal of up to 10 cm. Magnetic contact sensors can be hidden installation i.e. To be mounted so that outsiders are not visible (usually crashed into the door frames). If necessary, they are also mounted in window frames.
Vibration sensors are installed in places of a possible break in the walls and also on the walls near the safe and ATMs, are usually mounted together with IR volume sensors, etc. Perimeter security sensors – a special sensitive cable lies around the perimeter of the object, digging shallow in the ground. The distance from the fence can be from a meter to five (the free strip from the fence to the cable is called the alienation zone).
The perimeter radio wave sensors are located around the perimeter of the object on the poles at a height of about a meter above the ground with the exclusion zone several meters from the fence, since their sensitivity zone can go beyond. Attention, the sensor has a small area of sensitivity behind itself (receiving part). Between the blocks, the distance can be up to 300 m. The farther from each other the transmitting and receiving blocks, the lower the sensitivity of the sensor will be lower.
Perimeter active IR sensors or in another way they are also called IR bargers – they can be located on small pillars on the fence so that the penetrating object crosses these rays. Also, several pieces in a row that overlap human growth can also be located on separate pillars.
An alarm buttons are usually installed in banks and box office. They are located fixed under the table at the workplace of the cashier and in any other places that are easy to reach. Combined into one train. An alarming buttons – the radio on the contrary – carry with them because Their advantage is mobility.