Classifications

• • G—PHYSICS
  • G08—SIGNALLING
  • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
  • G08B7/00—Signalling systems according to more than one of groups G08B3/00 - G08B6/00; Personal calling systems according to more than one of groups G08B3/00 - G08B6/00
  • G08B7/06—Signalling systems according to more than one of groups G08B3/00 - G08B6/00; Personal calling systems according to more than one of groups G08B3/00 - G08B6/00 using electric transmission, e.g. involving audible and visible signalling through the use of sound and light sources
• • G—PHYSICS
  • G08—SIGNALLING
  • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
  • G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
  • G08B29/02—Monitoring continuously signalling or alarm systems
  • G08B29/10—Monitoring of the annunciator circuits

Definitions

• the present invention relates to an evacuation alarm system which is intended for use in buildings and within small outdoor areas and which comprises a new data network which, structurally and functionally, is similar to the telecommunication network but has been developed so that it can within small areas up to a few kilometers serve for the purpose of transmitting data and digital sound.
• power supply has been integrated into the system.
• the data transmission is also used for the purpose of super- vising the system.
• the modular structure permits simple expansion, the addition of loop-shaped or star-shaped networks and the choice between external or internal current supply. Thanks to the fact that a supervision function has been implemented already from the outset, it has been possible to maintain and to secure the operational reliability of the system also during exceptional circumstances. Altogether this amounts to substantial advan- tages in comparison with analogous networks of prior art types. Normally, it is possible to upgrade existing, analogous networks to a system according to the invention without having to install a new cable.
• the base of the system is the centrally disposed network server, the main purpose of which is to formate incoming data to the protocol used in the network, to transmit and supervise data in the network and, when this is needed, to release an alarm.
• the server is available in different shapes and does normally cooperate with means for current supply, data multiplexing and studio equipment, if any.
• the receivers are so- called terminals which can have several functions in addition to the data reception and transmission proper.
• a terminal may communicate with other units, serve as a digital/analogous converter for the regeneration of sound or serve as an interface to other units etcetera.
• the object of the present invention is to provide an evacuation alarm system of the type above defined which in an excellent way satisfies its purposes, the system being at the same time very flexible and can be adapted to match most needs in respect of analogous and digital transmission. Also, it is possible to mix different groups of services without jeo- pardizing the operational reliability and function of the system.
• Fig. 1 is a block diagram illustrating an alarm unit forming part of the system according to the invention.
• Fig. 2 comprises two curve diagrams, the upper one indicating the power used in a thin cable and the lower one the transmitted, available average power in a cable having the same cross- sectional area.
• the communication in the system is concerned the data transmission, which is completely digital, occurs in a block pattern at a medium-high speed.
• the communication is two-way and data are transmitted in a time-multiplex form.
• the system handles this completely internally and the transmission of the data becomes fully transparent to the user.
• power from the network or from conventional power networks can be used directly or stored in the terminal.
• the system has integrated functions for the supervision of a mixed or completely decentralized current supply network.
• the system voltage can be selected in the range below 150 V but, normally, voltages higher than 50 V are not used.
• the cross-sectional area of the cable does not affect the data transmission but, in systems where high power levels are to be transmitted, attention must be paid to the area.
• the system permits use of a loop-shaped or star-shaped network.
• each terminal unit does, with the aid of its own computer, check that the communication is maintained and operates without any distur-nadoes, making it possible to create systems in which it is important upon interruption to reach a predetermined condition.
• Typical applications are evacuation alarm systems, liquid level control apparatus and equipment normally remote-controlled but capable of performing self-protecting functions.
• evacuation alarm systems liquid level control apparatus and equipment normally remote-controlled but capable of performing self-protecting functions.
• program programs By addition of different programs to the terminal units it is possible to create more complex systems and, by definition in advance of the situations which may arise, the handling of those situations can be carried out locally in accordance with a predefined condition master.
• Typical applications involve activation of flash bulbs, fire cells, ventilation and heat supervision equipment.
• the system can be continuously expanded in order to satisfy the existing different demands. However, it is compatible between the different versions due to the fact that the interfaces and the software are similar.
• the system according to the invention does, however, always transmit data in the digital form. This guarantees that no types of analogous distortion can arise and that the system can be installed and put into operation with the use of simple means.
• An evacuation alarm of the type here concerned can also be activated both by a digital transmission and by the absence of transmission.
• the transmission interruption control mode When the transmission interruption control mode is used, the division into groups must take place in such a way that the proper selective activation is achieved. Generally, this is a case already when, according to the invention, old analogous systems are upgraded to the data network.
• digital activation When digital activation is used, individual group or general calls can be made without any restrictions.
• the terminal unit can operate as a "stand-alone" termi- nal with a "phantom" current supply. Since it is possible to transmit a high level power, it becomes possible to control e.g. magnetic valves, illumination, door locks or motors. By charging locally available batteries additional power can be made available tempo- rarily or during a power failure.
• the software can permit local decisions based on incoming signals from different sensors. Often there exists in the system a need for a two-way communication to certain spots. By way of example, entrance supervising systems can be mentioned in which there exists a need for both internal communication and for gate control. Another example is an evacuation alarm system in which it is desirable to transmit messages for either immediate use or for storing in the terminal unit. Activation of the alarm system can occur centrally or decentralized. In this way a transmission interruption in the network caused by e.g. fire will always trigger the alarm. A high reliability can be achieved by means of a local battery which is charged and supervised via the network.
• a back-up battery provides continuous information about the status of the sensors connected to the terminal unit and this only in case of a power failure. This may be important in certain types of supervision at which normally automatic functions can be replaced by manual control, when necessary.
• acoustic signals may be fed to a loudspeaker via a cable, the impedance of which must as a rule be low to avoid high losses in the cable. This problem is normally solved by the use of so-called line transformers which reduce the current intensity and increase the voltage.
• the maximum power which then can be transmitted must be generated by a direct current. This power level can then cover considerably higher output power peaks than the average power value transmitted.
• the acoustic signal is in the shape of a "weak" signal superimposed upon the "power signal”. Accumulated power can then feed the loud-speaker up to the peak value power output.
• the weak sound signal is amplified meaning that the drive stage is at the loud-speaker.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Computer Security & Cryptography (AREA)
• Alarm Systems (AREA)
• Fire Alarms (AREA)

Applications Claiming Priority (5)

Publications (1)

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Country Status (4)

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• 1998
  • 1998-02-27 SE SE9800606A patent/SE9800606L/ not_active Application Discontinuation
  • 1998-08-21 EP EP98940746A patent/EP1016053A1/de not_active Withdrawn
  • 1998-08-21 AU AU88948/98A patent/AU8894898A/en not_active Abandoned
  • 1998-08-21 WO PCT/SE1998/001505 patent/WO1999010855A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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