Design: Configuration Of The Alarm System; Identifying The Grade Of Protection; The Alarm System Power Supply - Urmet 1068 Série Mode D'emploi

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DESIGN: CONFIGURATION OF THE ALARM SYSTEM

This chapter explains how to design an alarm system and provides the information necessary to make the most of the
features of the devices used and comply with the relevant regulations.
2.1

IDENTIFYING THE GRADE OF PROTECTION

The designer of the intrusion alarm system, in order to select the grade of protection, must take into consideration:

the nature of the rooms;

the value of the goods to be protected;

the potential risk of intrusion;

potential threat to people;

any other element that may be a cause of risk to people or property.
Once the designer has identified the necessary grade of protection, it is the responsibility of the installer to create the
intrusion alarm system with the correct level of security.
2.2

THE ALARM SYSTEM POWER SUPPLY

In order to function, an alarm system needs electrical energy, which can be supplied by either mains power supply, a
battery, or other instrument capable of generating or providing electrical current.
There are three types of configuration for providing the necessary electrical energy:
1. A primary power source, like the mains power supply, and a secondary source of power charged by the same
system, like a rechargeable battery that is charged automatically through a system component.
2. A primary power source, like the mains power supply, and a secondary power source not charged by the same
system, like a high-capacity, long-lifetime battery.
3. The only primary source with a finite capacity but that ensures extended duration, like a lithium battery.
The term "power supply" can be used to indicate any of these configurations.
The secondary power supply as a back-up to operate the alarm system in case of a breakdown or temporary loss of
primary power, making it possible to continue providing the protection for which it was installed.
The minimum duration of the power supply that must be ensured by the secondary source is specified by law.
During this period of time, which is measured in hours or tens of hours, normal functioning of the entire system must be
guaranteed, including alarm signals and other necessary notifications. The rule establishes that the higher the grade of
security of the system, the longer the minimum duration must be.
If the secondary power source cannot be recharged, the minimum durations double.
Obviously, systems can be created in which the duration of the secondary power supply is higher than the minimum
required, for example, by using batteries with a higher capacity. This minimum life spans may also be reduced, provided
that other conditions are in place.
For example, it is possible to do so if the breakdown as the primary power source is notified to an alarm reception centre
or to another remote centre, or if there is a supplementary primary power supply, like a generator, that immediately and
automatically replaces the main one if needed.
In the third type of power supply listed above, the primary source must guarantee long-term functioning. Standard require
that the battery be able to provide power for at least one year, under any usage conditions. Furthermore, the power
supply must generate a signal or a break-down message before the voltage diminishes to below the value necessary to
maintain normal functioning of the system.
The passage from the primary to secondary power supply takes place without modifying the status of the alarm system.
When there is this type of switching, notifications can be generated and sent, usually one to signal the lack of mains
power supply and successively, one for the reset of electrical power once the mains power supply has been restored.
The power supplies can be located in one or more components of the alarm system, or even in a separate box.
The power of the power supply is very important. It must not only be able to power the entire system at its maximum
rated absorption, but must also contemporaneously recharge the batter, up to 80% of its capacity, within a maximum
time established by law.
To this view, the higher the grade of security of the system, the quicker the recharging must be.
Below we examine the typical alarm systems, to understand how they are powered.
Particular or complex systems can have different configurations.
DS1068-017 12 LBT20717