Modern technologies in warning systems.

Modern technologies in warning systems.

One of the promising approaches is the creation of fully digital warning systems. Such systems are already offered on the market. Moreover, the creation of the most effective systems is the result of the collective efforts of Russian developers and specialists from leading companies in South Korea, Singapore and China. The use of digital warning systems allows solving complex problems of equipping such facilities as hotels, sports complexes, large structures and enterprises.

The main advantage of a digital warning system is the ability to build distributed sound systems on its basis. What do we mean when we talk about distributed systems? Often there is a task to combine several buildings (rooms) located from each other or from the central equipment at large distances (more than 1000 m) into a single sound system.
Traditionally, this problem is solved in the following way. A multi-zone notification system is selected. Large-section cables are laid, and signal losses over a distance are calculated. But sometimes problems arise, because often in remote buildings, zoning is also necessary. And here it becomes clear that there is not enough copper. For such problems, the use of a digital system is optimal. In addition, multi-channel systems with a wide range of tasks and the most intricate configurations of speaker lines are easily built on their basis.
The digital system is based on a sequential principle of information transmission (analogous to the RS-422 protocol). All information, which is 6 audio channels in 250 zones, 99 groups, is transmitted via twisted pairs. In addition, since the signals are low-level, the diameter of the pairs is not significant. To cover large distances, a repeater is installed every 1000 meters.
The basis of the system (Fig. 1)are just a few blocks capable of solving a wide range of tasks, namely:

1. Automatic emergency notification using a complex algorithm for up to 120 zones.
2. Control of 250 remote terminals.
3. Control of 99 zone groups.
4. Manual and automatic system control.
5. Working with an mp3 player.
6. Working with a weekly timer.

A personal computer with installed software controls a 6-channel audio processor via a COM port and an adapter. The output of the computer's sound card is connected to the audio input of the processor. A digital signal is formed at the processor output, which is fed to the terminal input. Loudspeakers are connected to the 100V output of the terminal.
A terminal is an amplifier or a zone selector. Each terminal is assigned (using an additional program) a unique address of the terminal itself and the zone. Several terminals can be assigned the same zone address. Terminals with identical zone addresses will form a group (of terminals).
Additional units can be connected to the system, significantly expanding its capabilities:

Connection of a telephone hybrid.
The structural diagram of a possible system is shown in Fig. 2.

The system can implement up to 250 zones with a possible division into 99 groups. Access to the zones is carried out both manually and automatically using both a computer and a central processor.
In emergency mode, the system can be controlled by 120 control signals («dry contact» or +24V) from the fire alarm control panel. These signals are sent to the computer controller input. The computer has software that provides a complex notification algorithm via one of the dedicated audio channels.
When a control signal («dry contact») is received from the GOChS unit, the emergency sound signal is sent to the terminals via the first (dedicated) channel of the processor.
Music sources are connected to additional inputs of the audio processor. The complex branching structure is achieved using splitters.
In addition to the computer, this system can be controlled by a central processor, on the front panel of which there is a convenient joystick and display. With the help of this unit, the entire system is controlled and monitored from the central equipment units to the end terminals.
With the help of the central processor, you can:

• turn on/off any music source;
• select an audio channel, select a track;
• control the distribution of supply voltage;
• control the audio matrix;
• select zones on remote terminals.

Up to 30 remote consoles can be connected to the system. They can be used to select zones, zone groups, all zones and make announcements in them via microphone. Consoles have a higher priority than music broadcasting.
An essential feature of such a system is that information is transmitted via a 4-pair cable (UTP type).
The signal can be transmitted over distances of up to 10 km. A repeater is installed every 1000 m.
The line of terminal amplifiers includes wall-mounted amplifiers (30W/100V) and rack-mounted amplifiers (350W/100V). Wall-mounted amplifiers are equipped with remote channel selectors and volume controls. Rack-mounted amplifiers have built-in volume controls and selectors located on the front panel. If the zone power exceeds 350 W, then an analog distributor is selected as a terminal. It is also used if this equipment needs to be connected to an existing warning system.