EP0066737A1 - Circuit arrangement for the transmission of measured values to a central station, especially for a fire signalling system - Google Patents

Circuit arrangement for the transmission of measured values to a central station, especially for a fire signalling system Download PDF

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Publication number
EP0066737A1
EP0066737A1 EP82104317A EP82104317A EP0066737A1 EP 0066737 A1 EP0066737 A1 EP 0066737A1 EP 82104317 A EP82104317 A EP 82104317A EP 82104317 A EP82104317 A EP 82104317A EP 0066737 A1 EP0066737 A1 EP 0066737A1
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EP
European Patent Office
Prior art keywords
pulses
wire line
monitoring
pulse
measured value
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EP82104317A
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German (de)
French (fr)
Inventor
Werner Ing.-Grad. Klett
Hans-Peter Dipl.-Ing. Baumann
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Hekatron GmbH
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Hekatron GmbH
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    • G—PHYSICS
    • G08—SIGNALLING
    • G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
    • G08B25/00—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems
    • G08B25/01—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium
    • G08B25/04—Alarm systems in which the location of the alarm condition is signalled to a central station, e.g. fire or police telegraphic systems characterised by the transmission medium using a single signalling line, e.g. in a closed loop
    • 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
    • G08B29/06—Monitoring of the line circuits, e.g. signalling of line faults

Definitions

  • the invention relates to a circuit arrangement for the transmission of measured values, in particular in a fire alarm system, to a control center in which a plurality of sensors (fire alarms) are connected in parallel on a two-wire line, via which the supply voltage for the sensors is simultaneously supplied, a measured value being provided by a local pulse generator controlled activation of a measured value shunt to the two-wire line for generating measured value pulses is formed.
  • Such a circuit is known from DE-OS 27 01 184. This circuit involves the transmission of measured values from a single transmitter, the measured values being represented by a specific pulse frequency assigned to the respective measured value.
  • the invention has for its object to feed and receive a plurality of transducers via the two-wire line, wherein each transmitting transducer is to be recognized in the control center and the functionality of the two-wire line is to be monitored over its entire length.
  • each transducer is provided with a pulse generator programmed to deliver an individual pulse code, the pulse code serving simultaneously as a measured value and in the control center as an address that can be evaluated behind a first threshold switch, and at the end of the two-wire line facing away from the control center Surveillance bypass, which is continuously switched in terms of pulses by means of a pulse generator also arranged at this end for generating monitoring pulses which can be evaluated in the control center behind a second threshold switch, the amplitude the monitoring pulses and the threshold value of the second threshold switch exceeded by them is substantially smaller than the amplitude of the pulse code and the threshold value of the first threshold switch exceeded by this.
  • the amplitude matching of the measured value pulses each sent in the form of a pulse code and the monitoring pulses ensures that the evaluation of a pulse code and the evaluation of the monitoring pulses do not interfere with one another.
  • the pulse code ensures that the individual detection of each transmitting transmitter is made possible in the control center, the amplitude-related separation of the pulse code and the monitoring pulses being made possible in circuit terms in a simple manner by appropriately set threshold switches. Because of their relatively small amplitude, the monitoring pulses are only passed on by the second threshold value switch, so that the presence of the monitoring pulses can then be evaluated on this.
  • the amplitude of the monitoring pulses does not reach the threshold of the first threshold switch, so that the monitoring pulses can only be evaluated by the second threshold switch.
  • the Meßwertimpulse occurring in the form of pulse codes exceeding the threshold value of the first S 'chwellwertschal- ters so that it switches through a respective received pulse code and therefore its evaluation.
  • the simultaneous occurrence of monitoring pulses together with a pulse code does not interfere with the evaluation of the latter, since this only results in a pulse-like overlay that is not noticed by the first threshold switch.
  • the second threshold switch which is matched to the monitoring pulses, also responds.
  • both a line break and a short circuit can be determined, since in both cases the monitoring pulses disappear at the entrance to the control center.
  • the threshold switch can also be used to determine whether the transducers supplied with supply voltage via the two-wire line have too high a current consumption, since in this case the pulse-wise addition of the shunt to the consumers formed by the transducers has a correspondingly less effect, so that only correspondingly low monitoring pulses arise, but which then can no longer exceed the threshold value of the second threshold switch, which thus signals the absence of the monitoring pulses at its output.
  • an RC element behind the second threshold switch in front of the control center the voltage at the capacitor of the RC element being kept below a threshold value by means of the pulse discharge carried out by means of the monitoring pulses switched through in the second threshold value switch, the exceeding of which indicates the absence of the monitoring pulses.
  • the FIG. Shows a two-wire line with the two wires 1 and 2, which extends over the sensors 3 and 4 designed as fire detectors.
  • the fire alarms 3 and 4 form shunts to the two-wire line 1/2.
  • the two-wire line 1/2 is drawn in dashed lines to indicate that a larger number of fire detectors can also be connected to the two-wire line 1/2.
  • the monitoring shunt 5 At the end of the two-wire line is the monitoring shunt 5, with which it is signaled to the control center 6 by emitting monitoring pulses that the two-wire line 1/2 is continuously in order.
  • the fire alarms 3, 4 are formed by shunts, in each of which a resistance 7,8 is shunted by means of the contact 9, 10 to the two-wire line 1/2.
  • the contacts 9/10 can be any type of contacts, in particular electronic contacts.
  • the contacts 9, 10 are controlled by means of the pulse generators 11, 12, which in turn are controlled by sensors 13, 14. In the case of the fire detection system shown here, the sensors 13, 14 put the associated pulse generators 11, 12 into operation when the sensors detect a fire, for example due to smoke. In this case, the contacts 9, 10 will be pulsed actuates and thus cause an impulsive increase in the quiescent current flowing the two-wire line 1/2.
  • This quiescent current is essentially determined by the current consumption of the sensors 13, 14 located in the shunt of the two-wire line 1/2, plus the current consumption of the monitoring shunt. 5 is coming.
  • the monitoring shunt 5 contains the pulse generator 15, which controls the contact 16 with the pulse, with which the resistor 17 is connected to the two-wire line 1/2. As long as the two-wire line 1/2 has no interruption, the pulse generator 15 of the monitoring shunt 5 receives current and thus actuates the contact 16 continuously in pulses.
  • the pulse generators 3 and 4 are those which are each programmed to deliver an individual pulse code. Such pulse codes are shown in the figure in the blocks representing the pulse generators 3 and 4. Such pulse generators are commercially available components, and corresponding evaluation circuits for the individual recognition of the individual pulse codes are also commercially available. When one of the sensors 13 or 14 responds, the associated pulse generator 11 or 12 delivers its individual pulse code by closing the contact 9 or 10 accordingly, whereby the respective pulse code is given as a measured value to the two-wire line 1/2.
  • the amplitude of the monitoring pulses supplied by the monitoring pulse generator 15 is substantially smaller than the amplitude of the pulse codes supplied by the pulse generators 11 and 12.
  • the two-wire line 1/2 is on the one hand connected to the voltage source 18 and on the other hand led to the resistor 19, which forms the termination of the two-wire line 1/2.
  • the capacitor 20 branches off from the resistor 19, which is used only for direct current decoupling and transmits the pulses arriving on line 2 unchanged. The pulses thus transmitted from the capacitor 20 then arrive at the first threshold switch 21 and the second threshold switch 22.
  • the threshold value of the first threshold switch 21 is set such that it switches through measured value pulses from the pulse generators 11 and 12 in the form of pulse codes, but not from the Pulse generator 15 triggered monitoring pulses, because of their much lower amplitude compared to the measured value pulses.
  • the second threshold switch 22 has a significantly lower threshold value, so that it switches through both the monitoring pulses and the measured value pulses.
  • the different setting of the two threshold switches 21 and 22 is indicated by the threshold level shown in each case.
  • monitoring pulses When monitoring pulses occur, they reach the first threshold switch 21 and the second threshold switch 22, but are only switched through by the latter and cause the transistor 23, to which the capacitor 25 is connected in parallel, to switch through.
  • the capacitor 25 is constantly charged from the voltage source 18 via the resistor 24.
  • the time constant determined by the resistor 24 and the capacitor 25 is chosen such that when monitoring pulses 15 occur, the capacitor 25 is repeatedly discharged in pulses, so that the voltage at its terminal 28 is kept constantly below a certain threshold value.
  • This threshold value is monitored by the further threshold switch 26 which, when its threshold value is exceeded, emits a signal which activates the signal generator 27.
  • the relevant pulse code 11, 12 appears on the two-wire line 1/2 and is transmitted to the first threshold switch 21 via the capacitor 20.
  • this threshold switch 21 switches through the pulses of the pulse code, which are then evaluated in a known manner by a subsequent evaluation circuit and converted into the display of an address on the display panel 30. This can be the display of a number or a specific illuminated sign.
  • evaluation circuits are commercially available.
  • the evaluation circuit 29 activates the signal transmitter 31, which, when its signal is emitted, indicates that one of the measurement transmitters has started to operate and there is therefore a fire.
  • pulse codes have a duration of only a few milliseconds, after which there is a pause. It is consequently possible, in the event of the response of a plurality of transducers 3, 4, to also evaluate them separately in the control center 6, since the case repeatedly occurs at short intervals that a pulse code appears during the pause between the delivery of the other pulse codes. As a result, the evaluation circuit 29 can recognize individual pulse codes one after the other and each store the addresses contained therein individually. This makes it possible to display the simultaneous response of several sensors.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Fire Alarms (AREA)

Abstract

In the invention, a plurality of fire sensors are allocated in parallel on a two-wire line via which at the same time the supply voltage for the fire sensors is provided. The measured value is formed by connecting, under the control of a local pulse generator, a measured value shunt to the two-wire line in order to generate measured value pulses. Each measured value generator (3, 4) is provided with a pulse generator (11, 12) programmed to emit an individual pulse code. The pulse code serves in the central station as an address which can be evaluated behind a first threshold value switch (21). At the end of the two-wire line (1, 2) facing away from the central station (6), there is a monitoring shunt (16, 17) which is permanently connected through by pulses by means of a pulse generator (15) also arranged at this end and , specifically, in order to generate monitoring pulses (15) which can be evaluated in the central station (6) behind a second threshold value switch (22). The amplitude of the monitoring pulses (15) and the threshold value, exceeded by them, of the second threshold value switch (22) is substantially smaller than the amplitude of the pulse code and the threshold value, exceeded by the latter, of the first threshold value switch (21). <IMAGE>

Description

Die Erfindung bezieht sich auf eine Schaltungsanordnung zur Übertragung von Meßwerten, insbesondere in einem Brandmeldesystem, zu einer Zentrale, bei dem mehrere Meßwertgeber (Feuermelder) parallel an einer Zweidrahtleitung liegen, über die gleichzeitig die Speisespannung für die Meßwertgeber geliefert wird, wobei ein Meßwert durch von einem örtlichen Impulsgenerator gesteuerte Einschaltung eines Meßwertnebenschlusses zu der Zweidrahtleitung zur Erzeugung von Meßwertimpulsen gebildet wird.The invention relates to a circuit arrangement for the transmission of measured values, in particular in a fire alarm system, to a control center in which a plurality of sensors (fire alarms) are connected in parallel on a two-wire line, via which the supply voltage for the sensors is simultaneously supplied, a measured value being provided by a local pulse generator controlled activation of a measured value shunt to the two-wire line for generating measured value pulses is formed.

Eine derartige Schaltung ist aus der DE-OS 27 01 184 bekannt. Bei dieser Schaltung handelt es sich um die Übertragung von Meßwerten eines einzigen Meßwertgebers, wobei die Meßwerte durch eine dem jeweiligen Meßwert zugeordnete bestimmte Impulsfrequenz dargestellt werden.Such a circuit is known from DE-OS 27 01 184. This circuit involves the transmission of measured values from a single transmitter, the measured values being represented by a specific pulse frequency assigned to the respective measured value.

Der Erfindung liegt die Aufgabe zugrunde, über die Zweidrahtleitung eine Mehrzahl von Meßwertgebern zu speisen und von diesen Signale zu empfangen, wobei in der Zentrale jeder sendende Meßwertgeber erkannt werden soll und die Zweidrahtleitung hinsichtlich ihrer Funktionsfähigkeit über ihre gesamte Länge zu überwachen ist.The invention has for its object to feed and receive a plurality of transducers via the two-wire line, wherein each transmitting transducer is to be recognized in the control center and the functionality of the two-wire line is to be monitored over its entire length.

Erfindungsgemäß geschieht dies dadurch, daß jeder Meßwertgeber mit einem auf die Abgabe eines individuellen Impulscode programmierten Impulsgenerator versehen ist, wobei der Impulscode gleichzeitig als Meßwert und in der Zentrale als hinter einem ersten Schwellwertschalter auswertbare Adresse dient, und an dem der Zentrale abgewandten Ende der Zweidrahtleitung ein Überwachungsnebenschluß liegt, der ständig impulsmäßig mittels eines ebenfalls an diesem Ende angeordneten Impulsgenerators zur Erzeugung von in der Zentrale hinter einem zweiten Schwellwertschalter auswertbaren Überwachungsimpulsen durchgeschaltet wird, wobei die Amplitude der überwachungsimpulse und der von diesen überschrittene Schwellwert des zweiten Schwellwertschalters wesentlich kleiner ist als die Amplitude des Impulscode und der von diesem überschrittene Schwellwert des ersten Schwellwertschalters.According to the invention, this is done in that each transducer is provided with a pulse generator programmed to deliver an individual pulse code, the pulse code serving simultaneously as a measured value and in the control center as an address that can be evaluated behind a first threshold switch, and at the end of the two-wire line facing away from the control center Surveillance bypass, which is continuously switched in terms of pulses by means of a pulse generator also arranged at this end for generating monitoring pulses which can be evaluated in the control center behind a second threshold switch, the amplitude the monitoring pulses and the threshold value of the second threshold switch exceeded by them is substantially smaller than the amplitude of the pulse code and the threshold value of the first threshold switch exceeded by this.

Bei dieser Schaltung wird durch die amplitudenmäßige Abstimmung der jeweils in Form eines Impulscode gesendeten Meßwertimpulse und der Überwachungsimpulse dafür gesorgt, daß die Auswertung eines Impulscode und die Auswertung der Überwachungsimpulse sich gegenseitig nicht stören. Der Impulscode sorgt dabei gleichzeitig dafür, daß in der Zentrale die individuelle Erkennung jedes sendenden Meßwertgebers ermöglicht wird, wobei die amplitudenmäßige Trennung des Impulscode und der Überwachungsimpulse schaltungstechnisch in einfacher Weise durch entsprechend eingestellte Schwellwertschalter ermöglicht wird. Die Überwachungsimpulse werden dabei wegen ihrer relativ kleinen Amplitude nur durch den zweiten Schwellwertschalter weitergegeben, so daß sich an diesem anschließend eine Auswertung des Vorhandenseins der Überwachungsimpulse ermöglichen läßt. Die Überwachungsimpulse erreichen mit ihrer Amplitude jedoch nicht den Schwellwert des ersten Schwellwertschalters, so daß eine Auswertung der Überwachungsimpulse für sich nur durch den zweiten Schwellwertschalter erfolgen kann. Die in Form von Impulscodes auftretenden Meßwertimpulse überschreiten jedoch den Schwellwert des ersten S'chwellwertschal- ters, so daß dieser einen jeweils empfangenen Impulscode durchschaltet und damit dessen Auswertung ermöglicht. Das gleichzeitige Auftreten von Uberwachungsimpulsen zusammen mit einem Impulscode stört die Auswertung des letzteren nicht, da hierdurch nur eine impulsmäßige Überlagerung stattfindet, die von dem ersten Schwellwertschalter nicht bemerkt wird. Es spricht zwar bei Auftreten eines Impulscodes auch der zweite Schwellwertschalter an, der auf die Überwachungsimpulse abgestimmt ist. Dies stört jedoch nicht die Funktion der hier zugrundeliegende Schaltungsanordnung, da das Auftreten eines Impulscodes in jedem Falle für einen Alarm ausgenutzt wird, so daß es dabei keine Rolle spielt, ob gleichzeitig Überwachungsimpulse auftreten oder nicht. Würde der Fall eintreten, daß die Zweidrahtleitung hinter einem sendenden Meßwertgeber . unterbrochen ist, also in der Zentrale keine überwachungsimpulse empfangen werden, so würde dies im Falle des Empfangs eines Impulscodes von einem Meßwertgeber, der noch vor der gestörten Stelle der Zweidrahtleitung liegt, die Auslösung eines Alarms ermöglichen, da der betreffende Impulscode normalerweise empfangen und ausgewertet werden könnte. Man kommt bei dieser Schaltungsanordnung mit relativ geringem Aufwand aus, da für die Erzeugung der Meßwertimpulse und die Erzeugung der Überwachungsimpulse jeweils das gleiche Prinzip verwendet wird, nämlich die Durchschaltung eines Nebenschlusses zur Zweidrahtleitung. Die Trennung von Meßwertimpulsen und Überwachungsimpulsen läßt sich ebenfalls schaltungstechnisch in einfacher Weise mittels der unterschiedlich eingestellten Schwellwertschalter bewerkstelligen.In this circuit, the amplitude matching of the measured value pulses each sent in the form of a pulse code and the monitoring pulses ensures that the evaluation of a pulse code and the evaluation of the monitoring pulses do not interfere with one another. At the same time, the pulse code ensures that the individual detection of each transmitting transmitter is made possible in the control center, the amplitude-related separation of the pulse code and the monitoring pulses being made possible in circuit terms in a simple manner by appropriately set threshold switches. Because of their relatively small amplitude, the monitoring pulses are only passed on by the second threshold value switch, so that the presence of the monitoring pulses can then be evaluated on this. However, the amplitude of the monitoring pulses does not reach the threshold of the first threshold switch, so that the monitoring pulses can only be evaluated by the second threshold switch. However, the Meßwertimpulse occurring in the form of pulse codes exceeding the threshold value of the first S 'chwellwertschal- ters, so that it switches through a respective received pulse code and therefore its evaluation. The simultaneous occurrence of monitoring pulses together with a pulse code does not interfere with the evaluation of the latter, since this only results in a pulse-like overlay that is not noticed by the first threshold switch. When a pulse code occurs, the second threshold switch, which is matched to the monitoring pulses, also responds. However, this does not interfere with the function of the here basic circuit arrangement, since the occurrence of a pulse code is always used for an alarm, so that it does not matter whether monitoring pulses occur at the same time or not. Would the case occur that the two-wire line behind a sending transmitter. is interrupted, i.e. no monitoring pulses are received at the control center, this would enable an alarm to be triggered if a pulse code is received from a transmitter, which is still in front of the faulty point on the two-wire line, since the pulse code in question is normally received and evaluated could. This circuit arrangement requires relatively little effort, since the same principle is used for the generation of the measured value pulses and the generation of the monitoring pulses, namely the connection of a shunt to the two-wire line. The separation of measured value pulses and monitoring pulses can also be accomplished in circuit terms in a simple manner by means of the differently set threshold switches.

Durch die Auswertung der Überwachungsimpulse mittels des zweiten Schwellwertschalters lassen sich sowohl Leitungsbruch als auch Leitungskurzschluß feststellen, da in beiden Fällen die Überwachungsimpulse am Eingang der Zentrale verschwinden. Darüberhinaus läßt sich durch den Schwellwertschalter auch feststellen, ob die über die Zweidrahtleitung mit Speisespannung versorgten Meßwertgeber einen zu großen Stromverbrauch aufweisen, da in diesem Falle nämlich das impulsweise Hinzutreten des Nebenschlusses zu den durch die Meßwertgeber gebildeten Verbrauchern entsprechend weniger auswirkt, wodurch nur entsprechend niedrige Überwachungsimpulse entstehen, die dann aber den Schwellwert des zweiten Schwellwertschalters nicht mehr überschreiten können, der damit an seinem Ausgang das Ausbleiben der Uberwachungsimpulse meldet.By evaluating the monitoring pulses by means of the second threshold switch, both a line break and a short circuit can be determined, since in both cases the monitoring pulses disappear at the entrance to the control center. In addition, the threshold switch can also be used to determine whether the transducers supplied with supply voltage via the two-wire line have too high a current consumption, since in this case the pulse-wise addition of the shunt to the consumers formed by the transducers has a correspondingly less effect, so that only correspondingly low monitoring pulses arise, but which then can no longer exceed the threshold value of the second threshold switch, which thus signals the absence of the monitoring pulses at its output.

Zur Erkennung des Vorhandenseins der Überwachungsimpulse sieht man in der Zentrale zweckmäßigerweise ein RC-Glied hinter dem zweiten Schwellwertschalter vor, wobei die Spannung am Kondensator des RC-Gliedes durch mittels der im zweiten SChwellwertschalter durchgeschalteten Überwachungsimpulse erfolgende impulsmäßige Entladung unter einem Schwellwert gehalten wird, dessen Überschreiten das Ausbleiben der Überwachungsimpulse anzeigt.To detect the presence of the monitoring pulses looks expediently, an RC element behind the second threshold switch in front of the control center, the voltage at the capacitor of the RC element being kept below a threshold value by means of the pulse discharge carried out by means of the monitoring pulses switched through in the second threshold value switch, the exceeding of which indicates the absence of the monitoring pulses.

In der Fig. ist ein Ausführungsbeispiel der Erfindung dargestellt.An embodiment of the invention is shown in the figure.

Die Fig. zeigt eine Zweidrahtleitung mit den beiden Adern 1 und 2, die sich über die als Feuermelder 3 und 4 ausgebildete Meßwertgeber erstreckt. Die Feuermelder 3 und 4 bilden dabei Nebenschlüsse zur Zweidrahtleitung 1/2. Zwischen den einzelnen Feuermeldern 3 und 4 ist die Zweidrahtleitung 1/2 gestrichelt gezeichnet, um anzudeuten, daß auch eine größere Zahl von Feuermeldern an die Zweidrahtleitung 1/2 anschaltbar ist. Am Ende der Zweidrahtleitung liegt der Überwachungsnebenschluß 5, mit dem zu der Zentrale 6 hin durch Abgabe von Überwachungsimpulsen signalisiert wird, daß die Zweidrahtleitung 1/2 durchgehend in Ordnung ist.The FIG. Shows a two-wire line with the two wires 1 and 2, which extends over the sensors 3 and 4 designed as fire detectors. The fire alarms 3 and 4 form shunts to the two-wire line 1/2. Between the individual fire detectors 3 and 4, the two-wire line 1/2 is drawn in dashed lines to indicate that a larger number of fire detectors can also be connected to the two-wire line 1/2. At the end of the two-wire line is the monitoring shunt 5, with which it is signaled to the control center 6 by emitting monitoring pulses that the two-wire line 1/2 is continuously in order.

Die Feuermelder 3,4 werden durch Meßwertnebenschlüsse gebildet, in denen jeweils ein Widerstand 7,8 impulsweise mittels des Kontaktes 9,10 zu der Zweidrahtleitung 1/2 in Nebenschluß gelegt wird. Bei den Kontakten 9/10 kann es sich um jede Art von Kontakten handeln, insbesondere elektronische Kontakte. Die Steuerung der Kontakte 9,10 erfolgt mittels der Impulsgeneratoren 11,12, die ihrerseits von Sensoren 13,14 gesteuert werden. Im Falle des hier dargestellten Brandmeldesystems setzen die Sensoren 13,14 die zugehörigen Impulsgeneratoren 11,12 in Betrieb, wenn die Sensoren beispielsweise durch Rauchentwicklung einen Brand feststellen. In diesem Falle werden die Kontakte 9,10 impulsweise betätigt und bewirken damit eine impulsweise Erhöhung des die Zweidrahtleitung 1/2 fließenden Ruhestromes. Dieser Ruhestrom wird im wesentlichen durch den Stromverbrauch der im Nebenschluß der Zweidrahtleitung 1/2 liegenden Sensoren 13,14 bestimmt, wozu noch der Stromverbrauch des Überwachungsnebenschlusses . 5 kommt. Der Überwachungsnebenschluß 5 enthält den Impulsgenerator 15, der impulsmäßig den Kontakt 16 steuert, mit dem der Widerstand 17 an die Zweidrahtleitung 1/2 angeschaltet wird. Solange die Zweidrahtleitung 1/2 keine Unterbrechung aufweist, erhält der Impulsgenerator 15 des Überwachungsnebenschlusses 5 Strom und betätigt damit ständig impulsweise den Kontakt 16.The fire alarms 3, 4 are formed by shunts, in each of which a resistance 7,8 is shunted by means of the contact 9, 10 to the two-wire line 1/2. The contacts 9/10 can be any type of contacts, in particular electronic contacts. The contacts 9, 10 are controlled by means of the pulse generators 11, 12, which in turn are controlled by sensors 13, 14. In the case of the fire detection system shown here, the sensors 13, 14 put the associated pulse generators 11, 12 into operation when the sensors detect a fire, for example due to smoke. In this case, the contacts 9, 10 will be pulsed actuates and thus cause an impulsive increase in the quiescent current flowing the two-wire line 1/2. This quiescent current is essentially determined by the current consumption of the sensors 13, 14 located in the shunt of the two-wire line 1/2, plus the current consumption of the monitoring shunt. 5 is coming. The monitoring shunt 5 contains the pulse generator 15, which controls the contact 16 with the pulse, with which the resistor 17 is connected to the two-wire line 1/2. As long as the two-wire line 1/2 has no interruption, the pulse generator 15 of the monitoring shunt 5 receives current and thus actuates the contact 16 continuously in pulses.

Bei den Impulsgeneratoren 3 und 4 handelt es sich um solche, die jeweils auf die Abgabe eines individuellen Impulscode programmiert sind. In der Fig. sind derartige Impulscode in die die Impulsgeneratoren 3 und 4 darstellenden Blöcke eingezeichnet. Derartige Impulsgeneratoren sind handelsübliche Bauelemente, entsprechende Auswerteschaltungen für das individuelle Erkennen der einzelnen Impulscodes sind ebenfalls im Handel erhältlich. Bei Ansprechen eines der Sensoren 13 oder 14 liefert also der zugehörige Impulsgenerator 11 bzw. 12 seinen individuellen Impulscode durch entsprechend impulsmäßiges Schließen des Kontaktes 9 bzw. 10, wodurch der jeweilige Impulscode als Meßwert auf die Zweidrahtleitung 1/2 gegeben wird.The pulse generators 3 and 4 are those which are each programmed to deliver an individual pulse code. Such pulse codes are shown in the figure in the blocks representing the pulse generators 3 and 4. Such pulse generators are commercially available components, and corresponding evaluation circuits for the individual recognition of the individual pulse codes are also commercially available. When one of the sensors 13 or 14 responds, the associated pulse generator 11 or 12 delivers its individual pulse code by closing the contact 9 or 10 accordingly, whereby the respective pulse code is given as a measured value to the two-wire line 1/2.

In der Fig. ist weiterhin durch entsprechende Zeichnungsweise angedeutet, daß die Amplitude der von dem Überwachungsimpulsgenerator 15 gelieferten Überwachungsimpulse wesentlich kleiner ist als die Amplitude der von den Impulsgeneratoren 11 und 12 gelieferten Impulscodes. Hierdurch ergibt sich nun in der Zentrale 6 eine technisch besonders günstige und betriebssichere Möglichkeit der Auswertung der überwachungsimpulse und der Impulscode. In der Zentrale 6 ist die Zweidrahtleitung 1/2 einerseits an die Spannungsquelle 18 und andererseits an den Widerstand 19 geführt, der hier den Abschluß der Zweidrahtleitung 1/2 bildet. Vom Widerstand 19 zweigt der Kondensator 20 ab, der lediglich zur gleichstrommäßigen Entkopplung dient und die auf der Leitung 2 ankommenden Impulse unverändert überträgt. Die somit von dem Kondensator 20 übertragenen Impulse gelangen dann zu dem ersten Schwellwertschalter 21 und dem zweiten Schwellwertschalter 22. Der erste Schwellwertschalter 21 ist hinsichtlich seines Schwellwertes so eingestellt, daß er inForm von Impulscodes vorliegenden Meßwertimpulsen der Impulsgeneratoren 11 und 12 durchschaltet, nicht jedoch die vom Impulsgenerator 15 ausgelösten Überwachungsimpulse, und zwar wegen deren wesentlich geringerer Amplitude gegenüber den Meßwertimpulsen. Der zweite Schwellwertschalter 22 besitzt einen demgegenüber wesentlich niedrigeren Schwellwert, so daß er sowohl die Überwachungsimpulse als auch die Meßwertimpulse durchschaltet. Die jeweils unterschiedliche Einstellung der beiden Schwellwertschalter 21 und 22 ist durch die jeweils eingezeichnete Schwellwertstufe angedeutet.In the figure, it is also indicated by a corresponding drawing that the amplitude of the monitoring pulses supplied by the monitoring pulse generator 15 is substantially smaller than the amplitude of the pulse codes supplied by the pulse generators 11 and 12. This now results in the control center 6 in a technically particularly favorable and reliable way of evaluating the monitoring pulses and the pulse code. In the control center 6, the two-wire line 1/2 is on the one hand connected to the voltage source 18 and on the other hand led to the resistor 19, which forms the termination of the two-wire line 1/2. The capacitor 20 branches off from the resistor 19, which is used only for direct current decoupling and transmits the pulses arriving on line 2 unchanged. The pulses thus transmitted from the capacitor 20 then arrive at the first threshold switch 21 and the second threshold switch 22. The threshold value of the first threshold switch 21 is set such that it switches through measured value pulses from the pulse generators 11 and 12 in the form of pulse codes, but not from the Pulse generator 15 triggered monitoring pulses, because of their much lower amplitude compared to the measured value pulses. The second threshold switch 22 has a significantly lower threshold value, so that it switches through both the monitoring pulses and the measured value pulses. The different setting of the two threshold switches 21 and 22 is indicated by the threshold level shown in each case.

Bei Auftreten von Überwachungsimpulsen gelangen diese zum ersten Schwellwertschalter 21 und zweiten Schwellwertschalter 22, werden jedoch nur von dem letzteren durchgeschaltet und bewirken eine Durchschaltung des Transistors 23, zu dem der Kondensator 25 parallel geschaltet ist. Der Kondensator 25 wird ständig aus der Spannungsquelle 18 über den Widerstand 24 aufgeladen. Die durch den Widerstand 24 und dem Kondensator 25 bestimmte Zeitkonstante so gewählt, daß bei Auftreten von Überwachungsimpulsen 15 der Kondensator 25 immer wieder impulsweise entladen wird, so daß die Spannung an seiner Klemme 28 ständig unterhalb eines bestimmten Schwellwertes gehalten wird. Dieser Schwellwert wird von dem weiteren Schwellwertschalter 26 überwacht, der bei Überschreiten seines Schwellwertes ein Signal abgibt, das den Signalgeber 27 aktiviert. Dieses Überschreiten des Schwellwertes aufgrund entsprechender Aufladung des Kondensators 25 tritt also dann ein, wenn aufgrund einer Unterbrechung der Zweidrahtleitung 1/2 der Überwachungsnebenschluß 17 außer Betrieb gesetzt wird, so daß die überwachungsimpulse 15 auf der Zweidrahtleitung 1/2 verschwinden. Es tritt dann keine impulsmäßige Entladung des Kondensators 25 mehr ein, so daß aufgrund der Aktivierung des Signalgebers 27 angezeigt wird, daß ein Leitungsbruch auf der Zweidrahtleitung 1/2 vorliegt. Der gleiche Effekt ergibt sich bei einem Kurzschluß auf der Zweidrahtleitung 1/2.When monitoring pulses occur, they reach the first threshold switch 21 and the second threshold switch 22, but are only switched through by the latter and cause the transistor 23, to which the capacitor 25 is connected in parallel, to switch through. The capacitor 25 is constantly charged from the voltage source 18 via the resistor 24. The time constant determined by the resistor 24 and the capacitor 25 is chosen such that when monitoring pulses 15 occur, the capacitor 25 is repeatedly discharged in pulses, so that the voltage at its terminal 28 is kept constantly below a certain threshold value. This threshold value is monitored by the further threshold switch 26 which, when its threshold value is exceeded, emits a signal which activates the signal generator 27. This exceeding of the threshold value due to the corresponding charging of the capacitor 25 therefore occurs when ½ of the two-wire line is interrupted Monitoring shunt 17 is put out of operation so that the monitoring pulses 15 on the two-wire line 1/2 disappear. There is then no more pulsed discharge of the capacitor 25, so that the activation of the signal generator 27 indicates that there is a line break on the two-wire line 1/2. The same effect occurs with a short circuit on the two-wire line 1/2.

Wird nun in der oben beschriebenen Weise ein Meßwertgeber 3,4 in Tätigkeit gesetzt, so erscheint der betreffende Impulscode 11,12 auf der Zweidrahtleitung 1/2 und wird über den Kondensator 20 zu dem ersten Schwellwertschalter 21 übertragen. Dieser Schwellwertschalter 21 schaltet aufgrund seines entsprechend eingestellten Schwellwertes die Impulse des Impulscodes durch, die dann von einer anschließenden Auswerteschaltung in bekannter Weise ausgewertet und in die Anzeige einer Adresse auf dem Anzeigefeld 30 umgesetzt werden. Es kann sich dabei um die Anzeige einer Zahl oder eines bestimmten Leuchtzeichens handeln. Derartige Auswerteschaltungen sind, wie gesagt und im Handel erhältlich. Darüberhinaus wird durch die Auswerteschaltung 29 der Signalgeber 31 aktiviert, der mit Abgabe seines Signals anzeigt, daß, einer der Meßwertgeber in Tätigkeit getreten ist und somit ein Brand vorliegt.If a transducer 3, 4 is now activated in the manner described above, the relevant pulse code 11, 12 appears on the two-wire line 1/2 and is transmitted to the first threshold switch 21 via the capacitor 20. On the basis of its correspondingly set threshold value, this threshold switch 21 switches through the pulses of the pulse code, which are then evaluated in a known manner by a subsequent evaluation circuit and converted into the display of an address on the display panel 30. This can be the display of a number or a specific illuminated sign. As mentioned, such evaluation circuits are commercially available. In addition, the evaluation circuit 29 activates the signal transmitter 31, which, when its signal is emitted, indicates that one of the measurement transmitters has started to operate and there is therefore a fire.

Solange die Aktivierung eines Impulsgenerators 3/4 anhält, gibt dieser wiederkehrend seinen Impulscode ab. Derartige Impulscode haben eine Dauer von nur wenigen Millisekunden, wonach jeweils eine Pause eintritt. Es ist infolgedessen möglich, im Falle des Ansprechens mehrerer Meßwertgeber 3,4 diese in der Zentrale 6 auch gesondert auszuwerten, da hierbei in kurzen Zeitabständen immer wieder der Fall eintritt, daß ein Impulscode in der Pause zwischen der Abgabe der anderen Impulscodes erscheint. Infolgedessen kann die Auswerteschaltung 29 nacheinander einzelne Impulscodes erkennen und die darin enthaltenen Adressen jeweils einzeln abspeichern. Hierdurch ergibt sich die Möglichkeit, auch das gleichzeitige Ansprechen mehrerer Meßwertgeber anzuzeigen.As long as the activation of a pulse generator 3/4 continues, it will repeatedly give out its pulse code. Such pulse codes have a duration of only a few milliseconds, after which there is a pause. It is consequently possible, in the event of the response of a plurality of transducers 3, 4, to also evaluate them separately in the control center 6, since the case repeatedly occurs at short intervals that a pulse code appears during the pause between the delivery of the other pulse codes. As a result, the evaluation circuit 29 can recognize individual pulse codes one after the other and each store the addresses contained therein individually. This makes it possible to display the simultaneous response of several sensors.

Claims (2)

1. Schaltungsanordnung zur Übertragung von Meßwerten, insbesondere in einem Brandmeldesystem, zu einer Zentrale, bei dem mehrere Meßwertgeber (Feuermelder) parallel an einer Zweidrahtleitung liegen, über die gleichzeitig die Speisespannung für die Meßwertgeber geliefert wird, wobei ein Meßwert durch von einem örtlichen Impulsgenerator gesteuerte Einschaltung eines Meßwertnebenschlusses zu der Zweidrahtleitung zur Erzeugung von Meßwertimpulsen gebildet wird, dadurch gekennzeichnet, daß jeder Meßwertgeber (3,4) mit einem auf die Abgabe eines individuellen Impulscode programmierten Impulsgenerator (11,12) versehen ist, wobei der Impulscode gleichzeitig als Meßwert und in der Zentrale (6) als hinter einem ersten Schwellwertschalter (21) auswertbare Adresse dient, und an dem der Zentrale (6) abgewandten Ende der Zweidrahtleitung (1,2) ein Überwachungsnebenschluß (16,17) liegt, der ständig impulsmäßig mittels eines ebenfalls an diesem Ende angeordneten Impulsgenerators (15) zur Erzeugung von in der Zentrale (6) hinter einem zweiten Schwellwertschalter (22) auswertbaren Überwachungsimpulsen (15) durchgeschaltet wird, wobei die Amplitude der Überwachungsimpulse (15) und der von diesen überschrittene Schwellwert des zweiten Schwellwertschalters (22) wesentlich kleiner ist als die Amplitude des Impulscode und der von diesem überschrittene Schwellwert des ersten Schwellwertschalters (21).1. Circuit arrangement for the transmission of measured values, in particular in a fire alarm system, to a control center in which a plurality of sensors (fire alarms) are connected in parallel on a two-wire line, via which the supply voltage for the sensors is simultaneously supplied, a measured value being controlled by a local pulse generator Switching on of a measured value bypass to the two-wire line for generating measured value pulses is formed, characterized in that each measured value transmitter (3, 4) is provided with a pulse generator (11, 12) programmed to deliver an individual pulse code, the pulse code being used simultaneously as a measured value and in the control center (6) serves as an address which can be evaluated behind a first threshold switch (21), and at the end of the two-wire line (1, 2) facing away from the control center (6) there is a monitoring bypass (16, 17) which is also continuously pulsed by means of a this end arranged pulse generator (15) for generating in the control center (6) behind a second threshold switch (22), evaluable monitoring pulses (15) are switched through, the amplitude of the monitoring pulses (15) and the threshold value of the second threshold switch (22) exceeded by them being significantly smaller than the amplitude of the pulse code and the threshold value of the first threshold switch (21) exceeded by this. 2. Schaltungsanordnung nach Anspruch 1, dadurch gekennzeichnet, daß hinter dem zweiten Schwellwertschalter (22) ein RC-Glied (24,25) geschaltet ist, wobei die Spannung am Kondensator (25) des RC-Gliedes durch mittels der vom zweiten Schwellwertschalter (26) durchgeschaltete Überwachungsimpulse (15) erfolgende impulsmäßige Entladung . unter einem Schwellwert gehalten wird, dessen Überschreiten das Ausbleiben der Überwachungsimpulse (15) anzeigt.2. Circuit arrangement according to claim 1, characterized in that an RC element (24, 25) is connected behind the second threshold switch (22), the voltage at the capacitor (25) of the RC element being by means of the second threshold switch (26 ) switched through monitoring pulses (15) pulse discharge. is kept below a threshold value, the exceeding of which indicates the absence of the monitoring pulses (15).
EP82104317A 1981-06-05 1982-05-17 Circuit arrangement for the transmission of measured values to a central station, especially for a fire signalling system Withdrawn EP0066737A1 (en)

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DE19813122474 DE3122474A1 (en) 1981-06-05 1981-06-05 "CIRCUIT ARRANGEMENT FOR TRANSMITTING MEASURED VALUES, IN PARTICULAR IN A FIRE DETECTING SYSTEM, TO A CENTRAL UNIT"
DE3122474 1981-06-05

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0460643A2 (en) * 1990-06-06 1991-12-11 Mitsubishi Denki Kabushiki Kaisha Emergency circuit for, e.g., numerical control unit

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1285921B (en) * 1965-08-21 1968-12-19 Holger Nilsen & Co As Automatic fire alarm system
CH495022A (en) * 1969-09-16 1970-08-15 Cerberus Ag Fire alarm system with a device for line monitoring
DE2351103A1 (en) * 1972-10-09 1974-04-25 Ericsson Telefon Ab L M CURRENT PULSE GENERATOR
FR2287075A1 (en) * 1974-10-02 1976-04-30 Cerberus Ag Electronic fire alarm network with minimized wiring - between the central control unit and the detactors and alarm devices incorporating certain equipment operational checks
DE2632738A1 (en) * 1976-07-21 1978-01-26 Securiton Ag Alarm circuit with central station and sensor contacts - has oscillator output coupled to voltage comparators detecting both break and short circuit conditions

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1285921B (en) * 1965-08-21 1968-12-19 Holger Nilsen & Co As Automatic fire alarm system
CH495022A (en) * 1969-09-16 1970-08-15 Cerberus Ag Fire alarm system with a device for line monitoring
DE2351103A1 (en) * 1972-10-09 1974-04-25 Ericsson Telefon Ab L M CURRENT PULSE GENERATOR
FR2287075A1 (en) * 1974-10-02 1976-04-30 Cerberus Ag Electronic fire alarm network with minimized wiring - between the central control unit and the detactors and alarm devices incorporating certain equipment operational checks
DE2632738A1 (en) * 1976-07-21 1978-01-26 Securiton Ag Alarm circuit with central station and sensor contacts - has oscillator output coupled to voltage comparators detecting both break and short circuit conditions

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0460643A2 (en) * 1990-06-06 1991-12-11 Mitsubishi Denki Kabushiki Kaisha Emergency circuit for, e.g., numerical control unit
EP0460643A3 (en) * 1990-06-06 1992-10-21 Mitsubishi Denki Kabushiki Kaisha Emergency circuit for, e.g., numerical control unit
US5297149A (en) * 1990-06-06 1994-03-22 Mitsubishi Denki Kabushiki Kaisha Emergency circuit for, e.g., numerical control unit

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