EP0156474A1 - Système d'alarme d'incendie - Google Patents

Système d'alarme d'incendie Download PDF

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Publication number
EP0156474A1
EP0156474A1 EP85300866A EP85300866A EP0156474A1 EP 0156474 A1 EP0156474 A1 EP 0156474A1 EP 85300866 A EP85300866 A EP 85300866A EP 85300866 A EP85300866 A EP 85300866A EP 0156474 A1 EP0156474 A1 EP 0156474A1
Authority
EP
European Patent Office
Prior art keywords
nodal
loop
supply
control means
primary
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP85300866A
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German (de)
English (en)
Inventor
Trevor Edwin Clegg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
TANN-SYNCHRONOME Ltd
Original Assignee
TANN-SYNCHRONOME Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by TANN-SYNCHRONOME Ltd filed Critical TANN-SYNCHRONOME Ltd
Publication of EP0156474A1 publication Critical patent/EP0156474A1/fr
Withdrawn legal-status Critical Current

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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B26/00—Alarm systems in which substations are interrogated in succession by a central station
    • G08B26/001—Alarm systems in which substations are interrogated in succession by a central station with individual interrogation of substations connected in parallel
    • G08B26/002—Alarm systems in which substations are interrogated in succession by a central station with individual interrogation of substations connected in parallel only replying the state of the sensor
    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B26/00—Alarm systems in which substations are interrogated in succession by a central station
    • G08B26/005—Alarm systems in which substations are interrogated in succession by a central station with substations connected in series, e.g. cascade

Definitions

  • the present invention relates to a communicator system and has particular reference to a communication system for use with fire, intruder and access systems incorporating the advantages of a microprocessor and associated technology.
  • Many proposals have been advanced for the use of microprocessor technology in the use of fire intruder and access systems.
  • proposals have been submitted for a pair of ring circuit conductors to be placed in a building in which alarm indications are desired, the ring conductors being connected to central processing means either within the building or via modems externally therefrom.
  • Detectors/sensors are connected at spaced intervals along said conductors; such a system generally operates on the basis that the central processing system will sequentially or systematically interrogate each detector/sensor connected across the pair of ring conductors.
  • the ring conductors in this case are used as a source of both general power and as a communication means to the central processor.
  • Such a system operates by the transmission of digital data between the central processor and the various sensors and detectors in the ring circuit.
  • the present applicants have devised a general improvement in communications systems which seeks to overcome the problem of using high quality electrical conductors in such fire alarm systems.
  • an alarm system comprising
  • the present invention has the advantage, therefore, that the units react to a break or short in the main and/or subsidiary loops to switch out or isolate the break or short and communications are provided around a loop, this means that the breaking of that loop allows communication from either direction-
  • the control means preferably permits reading of data from and to each nodal unit and sensor in either direction either in the main and/or subsidiary conductor loops.
  • the communication system in accordance with the present invention may be a burglar alarm system, a fire alarm system an access control system, a system for monitoring and controlling the energy requirements of a building or a combination of some or all of these.
  • the control means may include a microprocessor capable of reading analog data and/or digital data supplied from a sensor to the processor in the control means. The said processor may then examine, store and collate the information received to identify whether a situation is normal or whether there is a potential alarm condition, or if there are any abnormal signals as a result of a system fault.
  • the control means may drive peripheral devices such as visual display units and printers and may provide automatic communications via telephone and/or radio in the event of a fault or alarm being diagnosed and may be provided with means selectively for calling police fire or maintenance services depending upon the nature of the alarm that is raised.
  • the sensors may be adapted to sense a fire or incipient fire condition and changes in sensor performance can be identified and the sensors themselves interrogated by the microprocessor provided in the control means.
  • the present invention also includes a communications system comprising central control means and a plurality of remote stations capable of communicating with said control means wherein the communication between said central control means and each remote station by means of at least one tone burst whereby data passing between control means and the remote station is determined by the duration and/or the number of tone bursts transmitted.
  • the control means may provide a trigger signal for response by remote stations and a trigger signal may preferably be of a different sense to the sense of a tone burst from the remote station.
  • the remote station may be nodal unit or sensor unit of the fire alarm system of the present invention.
  • each nodal unit and/or detector may be provided with a fault indication and control circuit:
  • a control circuit for switching a device to an alternative supply in response to a fault in a ring conductor loop including a pair of supply conductors may comprise transistor means for monitoring a potential difference between said pair of supply conductors, switching means capable of switching to isolate a portion of one of said supply conductors, said portion being connected via an operating device to the other of said supply conductors and diode means connecting said portion to said one supply conductor to bridge the or each switching means, the arrangement being such that in the event of a fall in the potential difference between said conductors below a thresh-hold due to a fault, the transistor causes or allows the switching means to act to isolate said portion from the fault whereby the operating device maintains its function via said diode-connection to a
  • a communication system in accordance with the present invention providing for interrogation of the sensors associated therewith may, in the case of a fire alarm, have the following features and advantages:-
  • the sensor in accordance with the present invention may be a fire sensor which will operate on one or more of the following principles:-
  • the sensors of the invention may include access control sensors, ultrasonic detectors, passive infra red detectors and microwave Deppler sensors.
  • the system in accordance with the present invention may be associated with an audible alarm such as an alarm bell or a siren.
  • a fire sensor may sense the environmental phenomenon to which it is sensitive, convert this to a digitally coded analogue signal for onward transmission to the control unit.
  • the control unit interprets the sequence of signals and communicates any deviation from normally expected trends, activate an audible alarm and where appropriate, activate suitable digital communications equipment for communication with fire, police and/or caretaking authorities.
  • the control means may act to operate a range of devices such as door release units, emergency lighting units, ventilators and so on.
  • the system illustrated in the accompanying drawing comprises a control unit indicated generally at 10 having a power supply 11 and a general output bus 12 for output equipment such as VDU's, printers, digital communicators and the like, all of known construction, configuration and function.
  • the control unit 10 may be supplied with an alarm line 13 having an audible alarm means 14, such, for example, as a bell.
  • the control unit 10 is provided with a main conductor ring 20 consisting of a pair of conductors 40+, 40" at a first end of loop 20 and 41+, 41" at a second end which extends as a closed ring around a building or area to be protected, the arrangement being such that the ring 20 is provided with power and/or signal input outout in each direction therearound.
  • the ring 20 is provided with a plurality of nodal units 21, 21', 22" coupled in series within main loop 20.
  • Each nodal unit 21 is provided with a pair of subsidiary ring conductors 22, each subsidiary ring conductors 22 having a plurality of sensors 23 which in the case of a fire alarm will be fire detectors, the fire detectors 23 being connected between the conductors consisting subsidiary ring 22 at spaced intervals therearound.
  • Each nodal unit 21 incorporates a series of switches which are capable, in response to a fault or a short circuit signal in the main ring 20, of opening switches to provide an open circuit.
  • Each of the detectors 23 in a subsidiary ring 22 are similarly provided with a switching means whereby in the event of a short circuit in a subsidiary ring at, for example point B, between detectors 23 and 23' of subsidiary ring 22 the detectors 23 and 23' would react to provide an open circuit each side of the short circuit at point B and yet each of detectors 23 and 23' would remain operative, since the current can flow and signals can pass from and to nodal unit 21" each way around the subsidiary ring 22.
  • the control unit 10 includes means for addressing sequentially nodal units 21 and then in sequence each of the detectors in the subsidiary ring 22 associated therewith and then proceed to the next nodal unit 21' and sequentially to each of the detectors in the subsidiary ring associated therewith and so on.
  • FIG. 5 is a block diagram of the line drive circuitry of control unit 10.
  • switches L, S, D, and Delta ( ⁇ ) are operated from a microprocessor board forming part of control unit 10.
  • Closing of switch D causes the voltage across the detector loop to drop to zero.
  • the detector loop components are preset by a long (in Figure 2, a 288 millisecond (ms)), positive pulse applied to the detector loop by closing switches L and S. This ensures that the first nodal unit 21 in the loop will be addressed first.
  • Subsequent negative going pulses 32 of duration 1.5 ms will address in sequence the individual detectors 23 associated with that particular nodal unit (21).
  • the next positive going pulse 33 of 100 ms duration addresses the next nodal unit 21' and the sequence is repeated for all the detectors 23' associated with that nodal unit. This is repeated until all the nodal units in the system have been addressed.
  • switches L and S are synchronous. During this initial 100ms period, however, switch L is on and S is off and during this period only switch delta ( ⁇ ) is open.
  • the detector will see the full length of pulse 31 since it will pass completely around main ring 20 from 40+, 40-, to 41+, 41-. If the ring 20 is open-circuited, then nodal units in certain sections will not receive the first 100ms of the pulse 31; this omission is registered by each of such nodal units to give a subsequent indication of the position of the open circuit fault when the said affected nodal units are addressed.
  • control unit 10 outputs a positive pulse or tone burst 31 of a duration in the specific example illustrated of 288 milliseconds. This pulse serves to zero sequentially all the nodal units and in their associated detectors in the ring 20.
  • the first nodal unit (21) in the ring 20 is activated to respond to an input pulse.
  • the initial pulse 31 causes nodal unit 21 to address sequentially each detector in it's subsidiary ring.
  • a pause in signal transmission of 202.5 milliseconds is allowed for nodal unit to reply and complete it's address of all the detectors 23 in its subsidiary ring B.
  • the first 12.8 milliseconds following the end of the tone burst 31 is permitted for a reply by the nodal unit itself as to the status of the node including any fault indications which are determined in the manner hereinafter described.
  • the return information is given by way of a negative pulse relative to the trigger pulse for the nodal unit 21 and the length of that tone burst determines the status of that node.
  • break glass window As hereinafter described.
  • the nodal unit itself is then caused to transmit a 1.5 millisecond negative pulse to address the first detector in the circuit.
  • the detector then has a period of 10.5 milliseconds within which to reply.
  • the length of the tone burst transmitted in that 10.5 millisecond period determines the nature of the reply.
  • a second pulse 32' triggers the response from the second detector in the subsidiary circuit to nodal unit 21 and so on.
  • nodal unit 21 will have completed it's address and will not be responsive to further short trigger pulses shorter than the 288 millisecond trigger pulse which initiates the sequence.
  • the control unit 10 provides a further pulse 33 of approximately 96 millisecond duration which then triggers the next nodal unit (21') in ring 20.
  • this nodal unit 21' repeats the sequence of addressing each detector in its circuit and at the completion of that address and response by the detectors, a nodal unit 21' is disenabled and a further 96 millisecond pulse activates the next nodal unit 21" in the circuit for response in a similar way.
  • This sequence continues until all the nodal units in circuit have addressed sequentially each of the detectors in their subsidiary circuit, all the responsive tone bursts having been fed back to the central control unit 10.
  • the period for complete address of a full system is 4.968 seconds.
  • the information collected in one complete sequence around the detection and nodal circuits will provide information which can be compared with datum information held in the control unit 10. Variations of any responses in terms of length of response pulses from both nodal unit status and detector units will indicate a change in status and will enable conditional information to be prepared by the computer or central control unit 10 as to the status of any or all of the detectors and any or all of the nodal units-
  • the detectors 23 can be the same or different'and once the steady state parameters have been determined any variation from that steady state parameter can be used and interpreted to produce a number of conditions between fault, caution, abnormal heating to full alarm.
  • Each or some of the nodal units 21 may include a manual alarm point such, for example, as a manual alarm of the break glass type.
  • a nodal unit When a nodal unit has a manual call point signal latched to it, it produces a 300 microsecond negative going response pulse to main loop 20 for detection by the detector loop at a time 17.5 ms after the next nodal address pulse 34 (see Figure 3). It should be noted that this occurs whether the particular nodal unit is being addressed or not. The detection of this pulse at the control unit 10 will result in a full alarm being transmitted by control unit 10 irrespective of the nodal status and detector status given elsewhere.
  • control unit 10 On receipt of a manual alarm pulse described above, the control unit 10 initiates a search procedure; a presetting positive pulse is transmitted and all the nodal units are sequenced in rapid succession; no detectors are addressed at this stage.
  • the total cycle time is 820ms and during this cycle the manual call point location can be determined and verified. 3 seconds after initiation of the manual call point signal, the said signal decays, thus allowing the system to revert to normal operation.
  • the particular nodal unit connected with the tripped manual alarm point will continue to give an alarm status signal during address by control unit 20 until such time as the call point and the associated nodal unit are reset.
  • the tone burst in this specific example operates at a frequency of 10 KHz and the nodal unit response is arranged to give a specific number of cycles at a nominal frequency of 10 KHz, the number of cycles being dependant on the appropriate conditions associated with that particular nodal unit, for example:-
  • the frequency response from individual detectors is such that the duration of the reply pulse train is an analogue representation of the sensed fire condition level. Under normal conditions, the duration is of the order of 3 ms; an increasing fire signal level will increase the duration of the pulse train.
  • each nodal unit 21 can distinguish different detector types within its subsidiary loop 22 as well as its location therein-In this embodiment the nominal response frequencies are as follows:-
  • Figure 6 shows the timing sequence of switches L, S, ⁇ , and D to produce the tone burst of Figures 2 and 3.
  • each nodal unit provides for the status of the detectors in each nodal unit loop 22 and the presence of faults to be communicated to the control unit 10.
  • the control unit operates with hexadecimal numbering with the nodal units being numbered zero to a maximum of 15 in the main ring and the detectors on each subsidiary ring being numbered 1 to 15 around the subsidiary ring.
  • the control unit 10 commences a sequence of address and provides a continuous scheduling address sequentially for each of the nodal units in the main ring.
  • the control unit will initially address nodal unit 21 (numbered zero) and then sequentially each of the detectors on each subsidiary ring 1 to F associated therewith.
  • the control unit 10 will then seek to address nodal unit 21' (numbered 1) and then each of detectors 0, 1, 27-8F in the subsidiary ring 22 associated therewith and so on completely around the main ring 20.
  • the period for a complete address will depend on the number of nodal units within a circuit and the number of detectors in each subsidiary circuit.
  • the main ring 20 comprises a pair of conductors 40 and 41 which form part of the main loop A+ and A- being on one side of the nodal unit 21 and B+ and B- being on the other.
  • the main ring circuit in this particular embodiment is provided with a take-off 42 from main conductor 41 and the main conductor 41 is capable of being provided with an isolated portion 43 juxtaposed the junction 42 with the main conductor 41 by means of a field effect transistors, 44/44 1 on each side of junction 43.
  • a load resistor 45 bridges main loop 41 A-, B- between field effect transistors 44/44' (see Figure 4).
  • Connection 42 is connected via the operating main body of the nodal unit to the positive conductor 40.
  • Positive conductor 40 is provided with a line connection 45 which is connected to provide a positive supply via 46 to the base of PNP transistor 47. This enables current flow via line connection 48 and transistor 47 and the associated circuitry to maintain the field effect transistors 44/44' closed thus connecting the main conductor A- and B- with isolatable portion 43 and nodal unit connection 42.
  • the particular advantage of the system described above is that it provides automatic switching in the event of a fault, it provides a clear indication of the area of the system in which the fault lies and it does not permit the fault to render any part of the circuit inoperative. Furthermore, the nature of the data transmission by means of tone bursts or time measured pulses does away with the problem of the transmission of direct digital information and the system as a wnole permits the use of a much cheaper wiring installation because of the ready indication of the fault. The system further reduces substantially the tendencies of such an automated fire alarm system to issue false alarms.

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  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Alarm Systems (AREA)
EP85300866A 1984-02-24 1985-02-08 Système d'alarme d'incendie Withdrawn EP0156474A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8404883 1984-02-24
GB8404883 1984-02-24

Publications (1)

Publication Number Publication Date
EP0156474A1 true EP0156474A1 (fr) 1985-10-02

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EP85300866A Withdrawn EP0156474A1 (fr) 1984-02-24 1985-02-08 Système d'alarme d'incendie

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CA (1) CA1225447A (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0319266A2 (fr) * 1987-11-30 1989-06-07 Hochiki Corporation Système d'alarme d'incendie
US9684286B2 (en) 2013-09-12 2017-06-20 Robert Bosch Gmbh Security system with point bus abstraction and partitioning

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3716834A (en) * 1971-10-07 1973-02-13 H Adams Data transmission system with immunity to circuit faults
US3815093A (en) * 1973-05-11 1974-06-04 Afa Syst Inc Signaling system utilizing frequency burst duration and absence for control functions
US3927404A (en) * 1973-10-18 1975-12-16 Standard Electric Time Corp Time division multiple access communication system for status monitoring
EP0111178A1 (fr) * 1982-11-23 1984-06-20 Cerberus Ag Dispositif de contrôle avec plusieurs détecteurs connectés, en forme de chaîne, à une ligne de signalisation
EP0111982A1 (fr) * 1982-12-17 1984-06-27 ADT, Inc. Système de sécurité intégré avec réglage multiprogrammé

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3716834A (en) * 1971-10-07 1973-02-13 H Adams Data transmission system with immunity to circuit faults
US3815093A (en) * 1973-05-11 1974-06-04 Afa Syst Inc Signaling system utilizing frequency burst duration and absence for control functions
US3927404A (en) * 1973-10-18 1975-12-16 Standard Electric Time Corp Time division multiple access communication system for status monitoring
EP0111178A1 (fr) * 1982-11-23 1984-06-20 Cerberus Ag Dispositif de contrôle avec plusieurs détecteurs connectés, en forme de chaîne, à une ligne de signalisation
EP0111982A1 (fr) * 1982-12-17 1984-06-27 ADT, Inc. Système de sécurité intégré avec réglage multiprogrammé

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0319266A2 (fr) * 1987-11-30 1989-06-07 Hochiki Corporation Système d'alarme d'incendie
EP0319266A3 (fr) * 1987-11-30 1991-01-30 Hochiki Corporation Système d'alarme d'incendie
US9684286B2 (en) 2013-09-12 2017-06-20 Robert Bosch Gmbh Security system with point bus abstraction and partitioning
EP2849163B1 (fr) * 2013-09-12 2018-12-05 Robert Bosch GmbH Système de sécurité avec abstraction de Bus et partitionnement des points

Also Published As

Publication number Publication date
CA1225447A (fr) 1987-08-11

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Inventor name: CLEGG, TREVOR EDWIN