GB2362490A

GB2362490A - Audio alarm system

Info

Publication number: GB2362490A
Application number: GB0011630A
Authority: GB
Inventors: Hoss Ghassan El
Original assignee: GLT EXPORTS Ltd
Current assignee: GLT EXPORTS Ltd
Priority date: 2000-05-15
Filing date: 2000-05-15
Publication date: 2001-11-21
Also published as: GB0011630D0; WO2001088873A1; AU2001258532A1

Abstract

An alarm system comprises a main control panel 10, a plurality of sounder units 12 and a plurality of detection units 16. Connected between the main control panel 10 and the sounder units 12 is a control unit 20. The sounder unit 12 comprises means for outputting one or more internally stored audible tones, means for receiving from an external source an audio signal, such as speech or music, and means for outputting the audio signal. The control unit 20 for controlling the sounder units 12 comprises means for transmitting an audio signal, such as speech, to one or more remote sounders for output thereby in response to a predetermined condition, and means for transmitting a signal to the one or more sounders 12 for indicating that the audio signal is to be output thereby.

Description

2362490 Alarm Svstems This invention relates to an alarm system and, in

particular but not exclusively, to an alarm system for use in warning occupants of a building of a potential hazard, such as fire and the like.

It is well known and, in fact, mandatory in most countries for companies in particular to provide a fire alarm system within their premises to warn occupants of the fact that there is a fire in the building. In many cases, a typical fire alarm system comprises an electronic control panel which, among other things, supplies and monitors power to a number of field devices. Such field devices typically include one or more detectors, such as heat or smoke detectors which transmit a signal to the control panel in the event of a fire being detected. One or more alarm sounders are also provided. When the control panel receives a signal from one or more of the heat or smoke detectors, indicating the presence of fire, it transmits signals to the or each alarm sounder to trigger a warning sound, such as a siren, therefrom. In general, and in the absence of instructions to the contrary, the occupants would evacuate the building according to some predetermined procedure.

1 As stated above, the alarm sounders may emit high frequency tones in the form of a siren or the like, or they may include memory means programmed with a speech message (during manufacture) which is broadcast from the sounder(s) in response to the signal from the control panel. In fact, a speech message has been found to be much more effective in eliciting the appropriate response from the occupants of a building. Research suggests that at least 90% of occupants will respond appropriately to a speech message giving instructions, whereas less than 50% of occupants are thought to give the same level of response to a siren or bell. However, sounders for emitting a speech message are relatively expensive, especially in view of the fact that the message any particular sounder emits must be fixed at the time of manufacture, so such sounders must effectively be custom-made for each customer. If it is required to change the message in any way, the sounders have to be removed and dismantled (by the manufacturer) and then reprogrammed. This is not only expensive and time-consuming, but also has to be done during a time when the building is not occupied and the alarm system is not required.

An arrangement has now been devised which overcomes the problems outlined above. In accordance with a first aspect of the present invention, there is provided a sounder unit comprising means for outputting one or more internally stored audible tones, means for receiving from an external source, an audio signal, such as speech or music, and means for outputting said audio signal.

The sounder preferably includes means for receiving an external indicator signal. The audible tones may in fact be one or more of high frequency tones, such as a siren, bells or even speech or music pre-programmed into a memory means within the sounder. The sounder preferably includes storage means in which is stored a plurality of stored tones, in which case the sounder beneficially includes switches or other selection means for selecting the tone to be output.

The audio signal may be pre-recorded and stored in an external, because sounder, recorded sounders external form of a message or warning can be output. the speech or audio signal is superimposed on the supply voltage to the sounder(s).

preferably reprogrammable memory means. Thus, the memory is reprogrammable and external to the any desired message or warning can easily be by the user, without the need to remove the Alternatively the sounder may be linked to an public address system, such that live speech in the In anv event The sounder beneficially includes means for receiving and recognising an initial external signal indicating a predetermined condition, for example, the presence of a hazard such as fire, and then for receiving and recognising a second signal indicating that speech is required to be output from the sounder.

When the sounder receives the initial signal indicating the predetermined condition, it may be arranged to automatically output the audible tone. Alternatively, a second signal may be required to trigger the audible tone output.

In accordance with a second aspect of the present invention, there is provided a control unit for controlling a sounder comprising means for outputting one or more audible tones stored therein, the control unit comprising means for transmitting an audio signal, such as speech, to one or more remote said sounders for output thereby in response to a predetermined condition, and means for transmitting a signal to said one or more sounders for indicating that said audio signal is to be output thereby.

The control unit may include memory means for receiving and storing audio signals, such as music or perhaps in the form of a verbal message or warning, and means for transmitting said audio signals to said one or more sounders in response to the predetermined condition. Alternatively, or in addition, the apparatus may include means for receiving and transmitting to said one or more sounders ',live,' audio signals, in particular, speech to emulate a public address system.

In all cases, the audio signals may be output by the sounder together with the audible tone(s) e.g. a siren, or as an alternative thereto. The tone (s) may sound only when no speech is required to be output.

The invention extends to an alarm system including a control panel, and at least one sounder according to the first aspect of the invention. In this case, the sounder would simply output tone(s)with which it is preprogrammed. In 5_ order to incorporate the speech capability into the system, the apparatus according to the second aspect of the invention may be connected between the control panel and one or more sounders. The advantage of using the apparatus according to the second aspect of the invention is that it can be simply connected at a single location in the circuit without requiring any additional inputs to the sounders.

An exemplary embodiment of the invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a block diagram of a typical alarm system according to the prior art;

Figure 2 is a block diagram of an alarm system including apparatus according to an exemplary embodiment of the present invention; and Figure 3 is a block circuit diagram of the sounder and control unit of Figure 2.

Referring to Figure 1 of the drawings, a known alarm system in a building, such as a shopping centre, typically comprises a main control panel 10 to which a plurality of sounder units 12 are connected via supply lines 14. The sounder units 12 are located at various appropriate positions around the building.

j Under normal conditions, the potential difference between the lines 14 is reversed or negative, such that the sounders 12 are in quiescent state, but the control panel can maintain the supply lines 14 to ensure their integrity.

The system also includes a plurality of detector units 16 also connected to the main control panel via supply lines 18. The detection units 16 are located at various appropriate positions around the building to detect the presence of, for example, a fire. In this case, the detection unis would comprise, for example, heat or smoke detectors.

In the event that one of the detector units 16 detects, say, smoke, it transmits a signal to the main control panel 10 via supply lines 18. In response to this signal, the main control panel 10 generates a positive voltage, for example, 24V across the supply lines 14 to the sounder units 12. The sounder units 12 include means (not shown) for monitoring the supply thereto. As explained above, under normal conditions, as the supply voltage from the main control panel 10 is reversed, the sounder units 12 are in a quiescent state. However, when the sounder units 12 detect the positive 24V signal on their supply lines, a microprocessor (not shown) in each sounder unit 12 is activated which causes the sounder to emit whatever warning signal it is programmed to emit. In many cases, the sounder units 12 are pre-programmed to emit one of a plurality of tones high frequency, for example a siren, according to -7 specific customer and legal requirements. In some cases, the sounder units include memory means on which a verbal warning message is pre- recorded during manufacture. The sounder unit 12 would then include amplifier and loudspeaker means (not shown) through which the message is broadcast.

It has been found that a relatively small percentage of people respond in the correct manner, or even at all, to tones such as sirens. However, speech evacuation sounders, although much more effective, are relatively very expensive, especially in view of the fact that they must be customised for every different alarm system.

Referring to Figure 2 of the drawings, an exemplary embodiment of an alarm system according to the present invention comprises a main control panel 10, a plurality of sounder units 12 and a plurality of detection units 16 as in the prior art system described with reference to Figure 1. However, connected between the main control panel 10 and the sounder units 12 is a control unit 20. Under normal conditions, the alarm system operates in substantially the same manner as described above with reference to Figure 1, in that the sounder units 12 are normally in a quiescent state because the voltage across the supply lines 14 is reversed or negative. The main control panel 10 monitors this negative voltage to ensure the integrity of the power supply lines 14 in the system is maintained.

Referring now in addition to Figure 3 of the drawings, there is shown a block circuit diagram of exemplary embodiments respectively of a control unit 20 and sounder unit 12 according to the present invention. The sounder unit 12 comprises supply monitoring means 22 for monitoring the supply across lines 14. As stated above, no supply would be detected because the supply voltage in the input circuit is reversed. When a positive voltage, e.g. the 24V signal mentioned above generated by the main control panel 10 in response to a signal from one of the detection units 16, the supply monitoring means 22 transmits a signal to a microprocessor 24 to activate it. As with prior art sounder units, the sounder 12 can be re-programmed to emit, via tone drive means 25 and output transducer 26, one of a plurality of high frequency tones, for example a siren, in response to the 24V signal. For this purpose, tone select input means 28 and alternate tone input means 30 are provided. Thus, if the sounder unit 12 is connected directly to the main control panel 10, the system operates substantially as described above with reference to Figure 1 of the drawings.

The control unit 20, has means 34 for receiving an input signal, such as the 24V signal referred to above, from the main control panel 10 in response to a signal from one of the detector units 16. The 24V signal is once again placed across the supply lines 14 to the sounder units 12 to activate the microprocessor 24. The control unit 20 includes means 36 for monitoring the input to the sounder units 12 from the main control panel 10 via input 34. The monitoring means 36 is connected to an input of a microprocessor 38. When the monitoring means 36 detects that a 24V signal has been transmitted to the sounder units to activate them, it transmits a signal to the microprocessor 38 to activate it.

The control unit 20 includes signal routing and audio control means 40 for receiving speech or other audio signals, either from an external source such as a public address system 42, a microphone 44 which may be built into the unit 20, or a non-volatile memory means 44 having a prerecorded message, either by the user (at 47) or the manufacturer. The mode of operation of the unit may be set by the user via the mode of operation input select means 46.

If it is required to broadcast a verbal message, either live or recorded, through the sounder units 12, it is necessary to indicate this to the sounder units 12. Any variation in the sounder input signal is suitable for this purpose. Thus, one or more high voltage pulses could be transmitted to the sounder units 12 to indicate the required mode of operation. Alternatively, the supply voltage could be momentarily reduced, removed or reversed. Many variations are envisaged. The supply monitoring means 22 in the sounder unit 12 detects the variation in supply voltage and transmits a signal to the microprocessor 24 to indicate that, instead of or in addition to emitting the preprogrammed high frequency tones, the sounder unit 12 is also required to output the signals received from the control unit 2 0. The speech or other audio signals from the control unit 20 are then processed and output via the speech drive means 50 and output transducer 26.

- 1 0 Thus, the sounder units 12 of the present invention can be connected directly to a control panel 10 in an alarm system so that the system operates in the conventional manner. However, it is a simple matter to connect a control unit 20 into the circuit (even after the system has been installed) to enhance the system user defined speech and other audio broadcast capability.

Although a specific exemplary embodiment of the invention has been described above, many modifications and varieties of the invention are envisaged, and will be apparent to a person skilled in the art. For example, the entire system could be used as a combined public address and alarm system, with the option of playing background music through the sounder units (via the control unit) when there is no hazard and no message is required to be broadcast.

It is even envisaged that alarm systems in various locations could be connected together in the form of a network so that their operation can be controlled from a single location.

In summary, the second aspect of the invention concerns an electronic control unit that will automatically switch between operating a sounder unit from its standard tonal output, controlled internally, to that of an audio/speech output using standard two wire connectivity, standard line integrity monitoring techniques and control signalling to which the sounder units of the first aspect of the invention respond to accordingly.

The control unit is intended for both "initial-,, or "retro-11 fitting such that if the sounder units, but not the control unit, are fitted at the initial installation, the complete system, as is, can be converted to a "combined speech/tonal alert/evacuate" system simply by inserting this control unit within the connecting wiring between the initiating control and indicating equipment and the sounder units.

operation and change-over control is achieved within the control unit by means of specific signalling techniques to the sounder units. For example, if the sounder units have a normal tonal operation supply between two predetermined levels, say, 10-SOVdc, supplied with a voltage within this range, they will output a tone according to their own internal selected setting. When subjected to a coded supply voltage variable in level and applied duration as a means of command communication and after a predetermined registration and verification time, they will then expect the inlet supply to change to that of a voltage capable of driving a speaker with an audio speech output. When the inlet voltage supply falls to below a predetermined level for a predetermined period of time, the sounder units will reset, expecting a new or similar command sequence to follow.

Should the control unit be inserted in the wiring between the initiating control and indicating equipment and the sounder units, it will, in its quiescent non-operational state, allow the control and indicating equipment to monitor the cabling in its normal manner to comply with codes of practice under which it may have been installed.

The audio signal, which may be a speech message, is held in the control unit and sent as a common signal to all of the sounder units that are connected to it. This audio signal may be pre-recorded, or recorded "onsite" by virtue of an in-built microphone and processing circuitry.

The control unit has selectable operation settings, allowing it to operate in a variety of modes, including, but not limited to, bypass (tonal operation only), override (audio signal operation only), alternating (between tonal and audio) plus other modes to suit its functional or system requirements.

The control unit preferably has no power supply of its own, but is instead reliant on either the control and indicating equipment or an external power supply with a specification to satisfy the requirements of the control unit and any codes of practice under which it may be installed.

Throughout the specification, the term "speech signals" is intended to cover speech and other audio signals such as music and the like.

Claims

CLAIMS:

1.

A sounder unit comprising means for outputting one or more internally stored audible tones, means for receiving from an external source, an audio signal, such as speech or music, and means for outputting said audio signal.

2. A sounder according to claim 1, including means for receiving an external indicator signal.

3. A sounder unit according to claim 1 or claim 2, wherein said audible tones comprise one or more of high frequency tones, speech or music preprogrammed into a memory means within the sounder unit.

4. A sounder unit according to any of claims 1 to 3, including storage means in which is stored a plurality of tones.

5. A sounder unit according to claim 4, including selection means for selecting the tone to be output.

6. A sounder unit according to any one of the preceding claims, wherein said audio signal is pre-recorded and stored in an external memory means.

A sounder unit according to claim 6, wherein said memory means is reprogrammable.

A sounder unit according to any one of the preceding claims, wherein said sounder unit is linked to an external public address system.

A sounder unit according to any one of the preceding claims wherein said speech or audio signal is superimposed on a supply voltage to said sounder unit.

10. A sounder unit according to any one of the preceding claims, including means for receiving and recognising an initial external signal indicating a predetermined condition, and for receiving and recognising a second signal indicating that speech is required to be output from the sounder unit.

A sounder unit according to claim 10, adapted to automatically output said audible tone in response to receipt of said initial signal indicating said predetermined condition.

12. A control unit for controlling a sounder comprising means for outputting one or more audible tones stored therein, the control unit comprising means for transmitting an audio signal, such as speech, to one or more remote said sounders for output thereby in response to a predetermined condition, and means for transmitting a signal to said one or more sounders for indicating that said audio signal is to be output thereby.

13. A control unit according to claim 12, including memory means for receiving and storing audio signals, and means for transmitting said audio signals to said one or more sounders in response to said predetermined condition.

14. A control unit according to claim 12 or claim 13, including means for receiving and transmitting said one or more sounders live audio signals to be transmitted thereby.

15. An alarm system including a control panel, and at least one sounder according to any one of claims 1 to 11.

16. An alarm system according to claim 15, including a control unit according to any one of claims 12 to 14 connected between said control panel and said one or more sounders.

17. A sounder unit substantially as herein described with reference to the accompanying drawings.

18. A control unit substantially as herein described with reference to the accompanying drawings.

16

19. An alarm system substantially as herein described with reference to the accompanying drawings.