EP0468234B1 - Method for increasing the fault security by risk signal systems - Google Patents
Method for increasing the fault security by risk signal systems Download PDFInfo
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- EP0468234B1 EP0468234B1 EP91110971A EP91110971A EP0468234B1 EP 0468234 B1 EP0468234 B1 EP 0468234B1 EP 91110971 A EP91110971 A EP 91110971A EP 91110971 A EP91110971 A EP 91110971A EP 0468234 B1 EP0468234 B1 EP 0468234B1
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- 238000000034 method Methods 0.000 title claims description 12
- 230000036039 immunity Effects 0.000 claims abstract description 4
- 230000005540 biological transmission Effects 0.000 claims description 18
- 238000001514 detection method Methods 0.000 claims description 2
- 238000011144 upstream manufacturing Methods 0.000 claims 2
- 125000004122 cyclic group Chemical group 0.000 claims 1
- 238000012546 transfer Methods 0.000 abstract description 2
- 230000011664 signaling Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 238000004891 communication Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 239000003990 capacitor Substances 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
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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
- G08B26/005—Alarm systems in which substations are interrogated in succession by a central station with substations connected in series, e.g. cascade
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- the invention relates to a method for increasing the immunity to interference in alarm systems with chain synchronization according to the preamble of claim 1.
- Transmission systems with chain synchronization work in such a way that the detectors arranged in the course of a double line, one after the other, are switched on in the line and then, immediately afterwards, send their message and / or receive a control command (DE-AS 25 33 354).
- DE-AS 25 33 354 a control command
- a switch is arranged in each detector, which is preferably formed by a switching transistor, which has the task of interrupting or connecting a wire of the double line if necessary.
- the message to be transmitted is formed by the time of the switching process.
- each detector switches on the following detector after a time delay (time slot) corresponding to its measured value, as described in DE-AS 25 33 382.
- An additional voltage pulse which is sent by the control center in this time slot, serves as a control command.
- Line interference now occurs due to the fact that the two wires of the double line are influenced by external electromagnetic interference.
- These disturbances can originate, for example, from other lines routed in the same cable or else originate from external sources of interference. In any case, they lead to interference on the two wires and are superimposed on the useful signals in such a way that, in the worst case, these are no longer correctly recognized and transmission errors occur.
- these interference voltages are essentially the same in size and direction. If very large interference voltages occur, for example due to lightning strikes in the immediate vicinity of the line, individual switches, which are usually field effect transistors, can be damaged so much that they can no longer close or that they remain permanently closed.
- the invention is based on the object of reducing the influence of the interference voltages coupled into the transmission line without reducing the transmission speed or jeopardizing compliance with the postal regulations due to excessive useful signals.
- the two-wire signaling line is balanced during the time of the information transmission from one detector to the control center.
- the information is only transmitted if all switching transistors, i.e. all detectors are switched through.
- the control center sends out pulses which cause the detectors to close their switching transistors, information being given by a detector only when the pulse reaches its input unchanged, a detector preceding a detector only then leaving the pulse unchanged let pass if he has already given information. This ensures that faults on both wires of the double line are of the same size and are compensated for with the help of the balun in the control center.
- control center sends short pulses which can be extended by a detector by actuating its switch, so that subsequent detectors cannot give any information.
- control panel sends long pulses that can be shortened by a detector by actuating its switch, so that subsequent detectors cannot give any information.
- FIG. 1 shows a hazard alarm system in which the individual detectors M1-Mn are connected to a control center Z via a double line a, b.
- each detector contains a switch S or switching transistor in each core of the double line a, b.
- the detector is connected to the control center via terminals a1 / b1.
- the capacitor C is charged via the diode D and, if there is no voltage on the line, supplies the detector electronics, which consist of the clock generator Ta and the signaling and control device M + S.
- the communication of the signaling and transmission device M + S with the control center Z takes place via the communication interface K.
- Switching transistors T1, T3, which are controlled directly or via a further transistor T2 by the signaling and control device M + S, are used for switching to the next detector, which is connected via the terminals a2 / b2 and a corresponding line section. Both switches realized by switching transistors T1, T3 are opened or closed together.
- FIG. 3 Another possible implementation of a hazard detector is shown in FIG. 3.
- This detector contains a switch implemented by a transistor T1 in only one wire.
- a resistor R for balancing the line is inserted in the other wire. If a detector contains a switch in only one wire of the double line, the line can only be balanced if all switches are connected by.
- the individual detectors are addressed by the pulses sent by the control center. A detector only provides information if these pulses reach its input unchanged and it has not yet given any information, the detector in question then leaving its switching transistor closed.
- Figure 4 shows possible voltage profiles on the individual detectors when the control panel sends short pulses.
- all switches are closed and the open circuit voltage UR is on the line.
- the control center applies the starting voltage US to the line in pulses. This opens the switches of all detectors.
- the control center applies the interrogation voltage UA to the line. Since all switches are open, the interrogation voltage is only at the input of the detector M1, so that only this is caused to issue its message at time t3. So that the line is symmetrical during the transmission, all switches are closed again at time t3.
- the control center again applies the starting voltage US to the line, whereupon all detectors which have not yet given a message open their switches again.
- the control center again applies the interrogation voltage UA to the line. Since the switch of detector M1 is closed, the interrogation voltage UA also reaches the input of detector M2. This causes the detector M2 to issue its message. After he has given his message, he also leaves his switch closed, regardless of the line voltage. This process continues until the last one Notifier has submitted his message. The control center then applies the open circuit voltage UR to the line again and starts the interrogation cycle again after some time.
- FIG. 5 shows the voltage profiles on the individual detectors when the control panel emits long pulses.
- the open circuit voltage UR is again on the line. All switches are closed.
- the line voltage from the control center is reduced to the start voltage US, the start voltage US being less than the quiescent voltage UR but greater than the query voltage UA.
- the switches are opened so that the input voltage on all detectors, except detector M1, drops to 0 volts.
- the long pulse only reaches the input of detector M1, which causes it to emit its message at time t3.
- all switches are closed again, so that the line is symmetrical during the information transmission.
- the starting voltage US is again applied to the line at time t4.
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- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
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Abstract
Description
Die Erfindung betrifft ein Verfahren zur Erhöhung der Störsicherheit bei Gefahrenmeldeanlagen mit Kettensynchronisation gemäß dem Oberbegriff des Anspruchs 1.The invention relates to a method for increasing the immunity to interference in alarm systems with chain synchronization according to the preamble of claim 1.
Übertragungssysteme mit Kettensynchronisation arbeiten derart, daß die im Zuge einer Doppelleitung angeordneten Melder, einer nach dem anderen, in der Leitung eingeschaltet werden und dann, direkt anschließend, ihre Meldung absetzen und/oder einen Steuerbefehl erhalten (DE-AS 25 33 354). Auf diese Weise ist es möglich, jedem Melder eine eindeutige Adresse zuzuordnen, ohne diese mit zusätzlichem apparatetechnischen oder bedienungstechnischen Aufwand einstellen zu müssen. Beim bekannten Pulsmeldersystem wird dazu in jedem Melder ein Schalter angeordnet, der vorzugsweise von einem Schalttransistor gebildet ist, der die Aufgabe hat, gegebenenfalls eine Ader der Doppelleitung zu unterbrechen bzw. durchzuverbinden. Die zu übertragende Meldung wird dabei durch den Zeitpunkt des Schaltvorganges gebildet. Das heißt, daß jeder Melder nach einer seinem Meßwert entsprechenden Zeitverzögerung (Zeitschlitz) den jeweils nachfolgenden Melder anschaltet, wie dies in der DE-AS 25 33 382 beschrieben ist. Als Steuerbefehl dient ein zusätzlicher Spannungsimpuls, der in diesem Zeitschlitz von der Zentrale gesendet wird. Soll nun eine größere Zahl von Informationen schnell sowohl in der Meldeals auch in der Steuerrichtung übertragen werden, so wird die Übertragungssicherheit zunehmend durch Störspannungen auf der Leitung gefährdet, weil einerseits die kürzeren Signale leichter gestört werden können und weil andererseits die Amplitude dieser Signale reduziert werden muß, um die Postvorschriften einzuhalten, während die Störungen gleich bleiben. Darüber hinaus muß mit einem Anwachsen der Störspannungen gerechnet werden, weil die elektromagnetische Verschmutzung durch z.B. Mobilfunk, Mikrowellengeräte, Leuchtstofflampen usw. generell zunimmt und andererseits in der Gefahrenmeldetechnik die Schleifentechnik an Bedeutung gewinnt, was aber zu längeren Leitungen und damit zu größeren Störbeeinflussungen führt. Über die angeführten Auswirkungen hinaus können besonders große Störbeeinflussungen komplette Übertragungseinrichtungen bzw. Teile von Übertragungseinrichtungen derart schädigen, daß auch nach dem Abklingen der Störung keine Übertragung mehr möglich ist. Ein bevorzugt gefährdetes Teil ist dabei der für die Leitungsunterbrechung verwendete Schalter bzw. Schalttransistor.Transmission systems with chain synchronization work in such a way that the detectors arranged in the course of a double line, one after the other, are switched on in the line and then, immediately afterwards, send their message and / or receive a control command (DE-AS 25 33 354). In this way, it is possible to assign a unique address to each detector without having to set it with additional equipment or operating technology. In the known pulse detector system, a switch is arranged in each detector, which is preferably formed by a switching transistor, which has the task of interrupting or connecting a wire of the double line if necessary. The message to be transmitted is formed by the time of the switching process. This means that each detector switches on the following detector after a time delay (time slot) corresponding to its measured value, as described in DE-AS 25 33 382. An additional voltage pulse, which is sent by the control center in this time slot, serves as a control command. If a larger amount of information is now to be transmitted quickly both in the message and in the control direction, the transmission security is increasingly endangered by interference voltages on the line, because on the one hand the shorter signals can be disturbed more easily and because on the other hand the amplitude of these signals must be reduced to the postal regulations to be observed while the disturbances remain the same. In addition, an increase in interference voltages must be expected, because electromagnetic pollution from e.g. mobile radio, microwave devices, fluorescent lamps etc. generally increases and, on the other hand, loop technology is becoming more important in hazard detection technology, but this leads to longer cables and thus greater interference. In addition to the effects mentioned, particularly large interference can damage complete transmission equipment or parts of transmission equipment in such a way that transmission is no longer possible even after the interference has subsided. A preferred endangered part is the switch or switching transistor used for the line interruption.
Zur Erhöhung der Störsicherheit ist es möglich, die Signalpegel zu vergrößern und damit auf die Einhaltung der Postvorschriften zu verzichten und in Folge davon auf ein eigenes Leitungsnetz angewiesen zu sein, ohne die Möglichkeit zu haben, vorhandene Fernmeldekabel mit zu benutzen. Außerdem ist es möglich, die Übertragungssicherheit durch von vornherein langsamere Übertragung und/oder durch mehrmalige Wiederholung desselben oder ähnlichen Signals zu steigern.To increase interference immunity, it is possible to increase the signal level and thus to dispense with compliance with the postal regulations and, as a result, to rely on your own network without being able to use existing telecommunications cables. In addition, it is possible to increase the transmission security by slower transmission from the outset and / or by repeating the same or similar signal several times.
Die Sicherheit gegen Zerstörung wird durch robuste Ausführung des Schalters und durch zusätzliche Schutzelemente wie Überspannungsableiter und Drosselspulen im Zuge der Leitung erhöht, was aber zusätzliche Bauteile erfordert und zu erhöhten Kosten führt.Protection against destruction is increased by the robust design of the switch and by additional protective elements such as surge arresters and choke coils in the course of the line, but this requires additional components and leads to increased costs.
Leitungsstörungen treten nun dadurch auf, daß die beiden Adern der Doppelleitung von äußeren elektromagnetischen Störungen beeinflußt werden. Diese Störungen können z.B. von im gleichen Kabel geführten anderen Leitungen ausgehen oder auch von äußeren Störquellen herrühren. Sie führen in jedem Fall zu Störungen auf den beiden Adern und überlagern sich den Nutzssignalen derart, daß im ungünstigen Fall diese nicht mehr richtig erkannt werden und somit Übertragungstörungen auftreten. Werden die beiden Adern in einem symmetrischen Kabel geführt, so sind diese Störspannungen nach Größe und Richtung im wesentlichen gleich. Treten sehr große Störspannungen auf, z.B. durch Blitzeinschläge in unmittelbarer Nähe der Leitung, so können dadurch einzelne Schalter, das sind in der Regel Feldeffekttransistoren, so beschädigt werden, daß sie nicht mehr schließen können oder daß sie dauernd geschlossen bleiben. Im ersteren, selteneren Fall ist nur eine Abfrage bis zu dem gestörten Melder möglich, im zweiten Fall wird der auf den gestörten Melder folgende gleichzeitig mit dem gestörten abgefragt, so daß sich deren Signale überlagern und schwer oder gar nicht auswertbar sind. Durch Symmetrierung der Leitungsanschaltung mittels eines Symmetrieübertragers ist es möglich, den Störspannungseinfluß zu vermindern, da dann nur die gegenphasigen Nutzsignale, nicht aber die gleichphasigen Störsignale ausgewertet werden. Das ist vorwiegend für die betriebsmäßigen, aber auch für die zerstörenden Störspannungen von Nutzen. Das Verfahren gelingt umso besser, je genauer die beiden gleichphasigen Störspannungen in ihrer Größe übereinstimmen.Line interference now occurs due to the fact that the two wires of the double line are influenced by external electromagnetic interference. These disturbances can originate, for example, from other lines routed in the same cable or else originate from external sources of interference. In any case, they lead to interference on the two wires and are superimposed on the useful signals in such a way that, in the worst case, these are no longer correctly recognized and transmission errors occur. If the two wires are routed in a symmetrical cable, these interference voltages are essentially the same in size and direction. If very large interference voltages occur, for example due to lightning strikes in the immediate vicinity of the line, individual switches, which are usually field effect transistors, can be damaged so much that they can no longer close or that they remain permanently closed. In the former, rarer case, only a query up to the faulty detector is possible; in the second case, the one following the faulty detector is queried simultaneously with the faulty one, so that their signals overlap and are difficult or impossible to evaluate. By balancing the line connection by means of a balun, it is possible to reduce the influence of the interference voltage, since only the antiphase useful signals are evaluated, but not the in-phase interference signals. This is primarily useful for operational, but also for destructive interference voltages. The method works better the more exactly the two in-phase interference voltages match in size.
Der Erfindung liegt nun die Aufgabe zugrunde, den Einfluß der auf die Übertragungsleitung eingekoppelten Störspannungen zu vermindern, ohne die Übertragungsgeschwindigkeit zu reduzieren oder die Einhaltung der Postvorschriften durch zu große Nutzsignale zu gefährden.The invention is based on the object of reducing the influence of the interference voltages coupled into the transmission line without reducing the transmission speed or jeopardizing compliance with the postal regulations due to excessive useful signals.
Die Aufgabe wird mit den Merkmalen des Anspruchs 1 gelöst. Ausgestaltungen der Erfindung sind den Unteransprüchen entnehmbar.The object is achieved with the features of claim 1. Embodiments of the invention can be found in the subclaims.
Bei dem eingangs beschriebenen Verfahren wird während der Zeit der Informationsübertragung von einem Melder zur Zentrale die zweiadrige Meldeleitung symmetriert. Dazu sind in dem Leitungszug, in dem kein Schalttransistor angeordnet ist, in jedem Melder entweder ein weiterer Schalttransistor oder ein Widerstand angeordnet, dessen Wert dem Durchlaßwiderstand des üblichen Schalttransistors entspricht. Die Informatiosübertragung erfolgt nur, wenn alle Schalttransistoren, d.h. alle Melder, durchgeschaltet sind. Dazu werden von der Zentrale aus Pulse ausgesandt, die die Melder veranlassen, ihre Schalttransistoren zu schließen, wobei eine Information von einem Melder nur dann abgegeben wird, wenn der Puls unverändert an seinen Eingang gelangt, wobei ein einem Melder vorausgehender Melder den Puls nur dann unverändert passieren läßt, wenn er bereits eine Information abgegeben hat. Dadurch wird erreicht, daß Störungen auf beiden Adern der Doppelleitung gleich groß sind und mit Hilfe des Symmetrierübertragers in der Zentrale kompensiert werden.In the method described in the introduction, the two-wire signaling line is balanced during the time of the information transmission from one detector to the control center. For this purpose, either a further switching transistor or a resistor, the value of which corresponds to the on-state resistance of the conventional switching transistor, is arranged in the detector in which no switching transistor is arranged. The information is only transmitted if all switching transistors, i.e. all detectors are switched through. For this purpose, the control center sends out pulses which cause the detectors to close their switching transistors, information being given by a detector only when the pulse reaches its input unchanged, a detector preceding a detector only then leaving the pulse unchanged let pass if he has already given information. This ensures that faults on both wires of the double line are of the same size and are compensated for with the help of the balun in the control center.
Bei der Symmetrierung der Doppelleitung durch eines in jedem Melder in jeder Ader angeordneten Schalttransistors, die jeweils gleichzeitig durchschalten, und zwar während der Informationsübertragung von einem Melder zur Zentrale, wird erreicht, daß die beiden Adern der Doppelleitung gleich lang sind und somit die Störungen gleich groß sind. Diese Anordnung von jeweils einem Schalttransistor in jedem Melder in der Doppelleitung hat auch noch den Vorteil, daß bei Zerstörung eines Leitungsschalters zumindest ein beschränkter Betrieb möglich bleibt. Eine Symmetrierung der Leitung mit einem in der Ader der Doppelleitung, die keinen Schalter aufweist, angeordneten Widerstand ist eine kostengünstigere Lösung möglich. Damit während der Informationsübertragung von einem der Melder zur Zentrale alle Schalter durchverbunden werden, sendet die Zentrale Pulse aus, die die Melder veranlassen, ihre Schalter zu schließen. Dabei wird eine Information von einem Melder nur dann abgegeben, wenn der von der Zentrale ausgesendete Puls unverändert an seinen Eingang gelangt, wobei ein einem Melder voranstehender Melder den Puls nur dann unverändert passieren läßt, wenn er bereits eine Information abgegeben hat.When the double line is symmetrized by a switching transistor arranged in each detector in each wire, which each switch simultaneously, during the transmission of information from one detector to the control center, it is achieved that the two wires of the double line are of the same length and thus the disturbances are equal are. This arrangement of one switching transistor in each detector in the double line also has the advantage that at least limited operation remains possible if a line switch is destroyed. Balancing the line with a resistor arranged in the core of the double line, which has no switch, is a more cost-effective solution. So that all switches are connected during the information transfer from one of the detectors to the control center the control panel sends out pulses that cause the detectors to close their switches. Information is only given by a detector if the pulse emitted by the control center arrives unchanged at its input, a detector preceding a detector only allowing the pulse to pass unchanged if it has already emitted information.
Eine Realisierungsmöglichkeit dieses Verfahrens ist dadurch gegeben, daß die Zentrale kurze Pulse sendet, die von einem Melder durch Betätigung seines Schalters verlängert werden können, so daß nachfolgende Melder keine Information abgeben können. Eine weitere Realisierung besteht darin, daß die Zentrale lange Pulse sendet, die von einem Melder durch Betätigung seines Schalters verkürzt werden können, so daß nachfolgende Melder keine Information abgeben können.One possibility for realizing this method is that the control center sends short pulses which can be extended by a detector by actuating its switch, so that subsequent detectors cannot give any information. Another implementation is that the control panel sends long pulses that can be shortened by a detector by actuating its switch, so that subsequent detectors cannot give any information.
Das erfindungsgemäße Verfahren soll anhand einiger Beispiele mit Hilfe der Figuren näher erläutert werden. Es zeigen
- Figur 1 eine mögliche Anordnung für das erfindungsgemäße Übertragungssystem,
- Figur 2 und 3 mögliche Realisierungen eines Gefahrenmelders,
- Figur 4 und 5 eine Darstellung der Spannungsverläufe an den einzelnen Meldern aufgrund der kurzen oder langen Pulse, die von der Zentrale ausgesendet werden.
- FIG. 1 shows a possible arrangement for the transmission system according to the invention,
- FIGS. 2 and 3 possible implementations of a hazard detector,
- Figures 4 and 5 show the voltage waveforms on the individual detectors due to the short or long pulses that are transmitted by the control center.
Figur 1 zeigt eine Gefahrenmeldeanlage, bei der über eine Doppelleitung a,b die einzelnen Melder M1-Mn mit einer Zentrale Z verbunden sind. Jeder Melder enthält neben den nicht dargestellten Einrichtungen für Meldungsempfang und Verarbeitung in jeder Ader der Doppelleitung a,b je einen Schalter S bzw. Schalttransistor.FIG. 1 shows a hazard alarm system in which the individual detectors M1-Mn are connected to a control center Z via a double line a, b. In addition to the devices for receiving and processing not shown, each detector contains a switch S or switching transistor in each core of the double line a, b.
In Fig. 2 ist eine mögliche Realisierung eines Gefahrenmelders dargestellt. Der Melder ist über die Klemmen a1/b1 zur Zentrale hin angeschlossen. Der Kondensator C wird über die Diode D aufgeladen und versorgt, wenn keine Spannung an der Leitung liegt, die Melderelektronik, die aus dem Taktgeber Ta und der Melde- und Steuereinrichtung M+S besteht. Die Kommunikation der Melde- und Sendeeinrichtung M+S mit der Zentrale Z findet über die Kommunikationsschnittstelle K statt. Zur Weiterschaltung zum nächsten Melder, der über die Klemmen a2/b2 und ein entsprechendes Leitungsstück angeschaltet wird, dienen Schalttransistoren T1,T3, die direkt oder über einen weiteren Transistor T2 von der Melde- und Steuereinrichtung M+S angesteuert werden. Beide durch Schalttransistoren T1,T3 realisierten Schalter werden gemeinsam geöffnet oder geschlossen. Auf diese Weise ist sichergestellt, daß Störspannungen hinter dem abzufragenden Melder keine der beiden Adern der Doppelleitung a,b beeinflussen, und damit die Störspannungen auf dem betriebenen Teil der Leitung gleich groß und gleichphasig sind. Wird durch eine sehr große Störspannung ein Schalter derart zerstört, daß er ständig leitet, so bleibt oft der andere wirksam und ermöglicht einen weiteren Betrieb, wenn auch mit höherem betriebsmäßigen Störspannungseinfluß. Darüber hinaus verbessert die symmetrische Anordnung der Schalter in beiden Adern der Übertragungsleitung die Leitungssymmetrie und damit Störbeeinflußbarkeit dadurch, daß sie die unvermeidbaren Schalterwiderstände nicht nur in einer Ader, sondern symmetrisch in beiden einfügt.2 shows a possible implementation of a hazard detector. The detector is connected to the control center via terminals a1 / b1. The capacitor C is charged via the diode D and, if there is no voltage on the line, supplies the detector electronics, which consist of the clock generator Ta and the signaling and control device M + S. The communication of the signaling and transmission device M + S with the control center Z takes place via the communication interface K. Switching transistors T1, T3, which are controlled directly or via a further transistor T2 by the signaling and control device M + S, are used for switching to the next detector, which is connected via the terminals a2 / b2 and a corresponding line section. Both switches realized by switching transistors T1, T3 are opened or closed together. In this way it is ensured that interference voltages behind the detector to be interrogated do not affect either of the two wires of the double line a, b, and thus the interference voltages on the operated part of the line are of the same size and in phase. If a switch is destroyed by a very large interference voltage in such a way that it constantly conducts, the other often remains effective and enables further operation, albeit with a higher operational interference voltage influence. In addition, the symmetrical arrangement of the switches in both cores of the transmission line improves the line symmetry and thus the ability to be influenced by interference by inserting the inevitable switch resistances not only in one core, but symmetrically in both.
Eine weitere mögliche Realisierung eines Gefahrenmelders ist in Figur 3 dargestellt. Dieser Melder enthält nur in einer Ader einen durch einen Transistor T1 realisierten Schalter. In der anderen Ader ist ein Widerstand R zur Symmetrierung der Leitung eingefügt. Enthält ein Melder nur in einer Ader der Doppelleitung einen Schalter, so kann eine Symetrierung der Leitung nur dadurch erfolgen, daß alle Schalter durch verbinden. Eine Adressierung der einzelnen Melder erfolgt durch die von der Zentrale gesendeten Pulse. Ein Melder gibt nur dann Informationen ab, wenn diese Pulse seinen Eingang unverändert erreichen und er bisher noch keine Information abgegeben hat, wobei der betreffende Melder dann seinen Schalttransistor geschlossen läßt.Another possible implementation of a hazard detector is shown in FIG. 3. This detector contains a switch implemented by a transistor T1 in only one wire. A resistor R for balancing the line is inserted in the other wire. If a detector contains a switch in only one wire of the double line, the line can only be balanced if all switches are connected by. The individual detectors are addressed by the pulses sent by the control center. A detector only provides information if these pulses reach its input unchanged and it has not yet given any information, the detector in question then leaving its switching transistor closed.
Figur 4 zeigt mögliche Spannungsverläufe an den einzelnen Meldern, wenn die Zentrale kurze Pulse sendet. Zunächst sind alle Schalter geschlossen und an der Leitung liegt die Ruhespannung UR. Zum Zeitpunkt tl wird von der Zentrale pulsweise die Startspannung US an die Leitung angelegt. Die Schalter aller Melder werden dadurch geöffnet. Zum Zeitpunkt t2 wird von der Zentrale die Abfragespannung UA an die Leitung gelegt. Da alle Schalter geöffnet sind, liegt die Abfragespannung nur am Eingang des Melders M1, so daß nur dieser veranlaßt wird, zum Zeitpunkt t3 seine Meldung abzugeben. Damit während der Übertragung die Leitung symmetrisch ist, werden zum Zeitpunkt t3 alle Schalter wieder geschlossen. Zum Zeitpunkt t4 wird von der Zentrale wieder die Startspannung US an die Leitung gelegt, worauf alle Melder, die noch keine Meldung abgegeben haben, ihren Schalter wieder öffnen. Zum Zeitpunkt t5 legt die Zentrale wieder die Abfragespannung UA an die Leitung. Da der Schalter des Melders M1 geschlossen ist, gelangt die Abfragespannung UA auch an den Eingang des Melders M2. Dadurch wird der Melder M2 veranlaßt, seine Meldung abzugeben. Nachdem er seine Meldung abgegeben hat, läßt auch er seinen Schalter, unabhängig von der Leitungsspannung, geschlossen. Dieses Verfahren wird fortgesetzt, bis der letzte Melder seine Meldung abgegeben hat. Die Zentrale legt dann wieder die Ruhespannung UR an die Leitung und beginnt nach einiger Zeit den Abfragezyklus aufs Neue.Figure 4 shows possible voltage profiles on the individual detectors when the control panel sends short pulses. First, all switches are closed and the open circuit voltage UR is on the line. At time t1, the control center applies the starting voltage US to the line in pulses. This opens the switches of all detectors. At time t2, the control center applies the interrogation voltage UA to the line. Since all switches are open, the interrogation voltage is only at the input of the detector M1, so that only this is caused to issue its message at time t3. So that the line is symmetrical during the transmission, all switches are closed again at time t3. At time t4, the control center again applies the starting voltage US to the line, whereupon all detectors which have not yet given a message open their switches again. At time t5, the control center again applies the interrogation voltage UA to the line. Since the switch of detector M1 is closed, the interrogation voltage UA also reaches the input of detector M2. This causes the detector M2 to issue its message. After he has given his message, he also leaves his switch closed, regardless of the line voltage. This process continues until the last one Notifier has submitted his message. The control center then applies the open circuit voltage UR to the line again and starts the interrogation cycle again after some time.
In Figur 5 sind die Spannungsverläufe an den einzelnen Meldern dargestellt, wenn die Zentrale lange Pulse aussendet. Zunächst liegt wieder die Ruhespannung UR an der Leitung. Alle Schalter sind geschlossen. Zum Zeitpunkt tl wird die Leitungsspannung von der Zentrale auf die Startspannung US reduziert, wobei die Startspannung US kleiner als die Ruhespannung UR, aber größer als die Abfragespannung UA ist. Zum Zeitpunkt t2 werden die Schalter geöffnet, so daß an allen Meldern, außer dem Melder M1, die Eingangsspannung auf 0 Volt absinkt. Dadurch gelangt der lange Puls nur an den Eingang des Melders M1, wodurch dieser veranlaßt wird, zum Zeitpunkt t3 seine Meldung abzugeben. Zu diesem Zeitpunkt werden auch wieder alle Schalter geschlossen, so daß während der Informationsübertragung die Leitung symmetrisch ist. Nachdem der Melder M1 seine Meldung abgegeben hat, wird zum Zeitpunkt t4 wieder die Startspannung US an die Leitung angelegt. Zum Zeitpunkt t5 öffnen alle Melder, die noch keine Meldung abgegeben haben, ihre Schalter wieder. Der lange Puls gelangt somit zum Melder M2, der dadurch veranlaßt wird, seine Meldung abzugeben. Dieses Verfahren wird fortgesetzt, bis alle Melder ihre Meldung abgegeben haben. Danach legt die Zentrale wieder die Ruhespannung UR an die Leitung und nach einiger Zeit beginnt der Abfragezyklus aufs Neue.5 shows the voltage profiles on the individual detectors when the control panel emits long pulses. First, the open circuit voltage UR is again on the line. All switches are closed. At time t1, the line voltage from the control center is reduced to the start voltage US, the start voltage US being less than the quiescent voltage UR but greater than the query voltage UA. At time t2, the switches are opened so that the input voltage on all detectors, except detector M1, drops to 0 volts. As a result, the long pulse only reaches the input of detector M1, which causes it to emit its message at time t3. At this point, all switches are closed again, so that the line is symmetrical during the information transmission. After the detector M1 has given its message, the starting voltage US is again applied to the line at time t4. At time t5, all detectors that have not yet submitted a message open their switches again. The long pulse thus arrives at detector M2, which is thereby caused to issue its message. This process continues until all detectors have submitted their report. The control center then applies the open circuit voltage UR to the line again and after a while the polling cycle begins again.
Claims (3)
- Method of increasing interference immunity in hazard detection systems having chain synchronization, the detectors (M1-Mn) being arranged in the course of a two-wire line (a,b) which is connected by means of a line connection to a central control station (Z), and at least one switch (S), in the form of a switching transistor, being provided in each detector for the purpose of interrupting or connecting through one of the lines, characterized in that in the cyclic interrogation of the detectors, during the transmission of information from a detector to the central control station (Z), the two wires (a, b) of the two-wire line are connected through symmetrically, that is to say with equal resistance ratios, for which purpose, on the one hand, there is arranged in each detector, in that line wire which has no switching transistor, either a further switching transistor or a resistor having a resistance value corresponding to the forward resistance of the switching transistor and, on the other hand, pulses are sent out by the central control station (Z) which cause the detectors to switch on their switching transistor or switching transistors, an item of information only being output by a detector if the pulse arrives unchanged at its input, a detector upstream of a detector only permitting the pulse to pass unchanged if the said upstream detector has already output an item of information.
- Method according to Claim 1, characterized in that the central control station (Z) sends short pulses which can be lengthened by a detector by actuating its switch (S), with the result that subsequent detectors cannot output information.
- Method according to Claim 1, characterized in that the central control station (Z) sends long pulses which can shortened by a detector by actuating its switch (S), with the result that subsequent detectors cannot output information.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4023766 | 1990-07-26 | ||
| DE4023766 | 1990-07-26 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0468234A2 EP0468234A2 (en) | 1992-01-29 |
| EP0468234A3 EP0468234A3 (en) | 1992-12-09 |
| EP0468234B1 true EP0468234B1 (en) | 1996-09-25 |
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ID=6411061
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP91110971A Expired - Lifetime EP0468234B1 (en) | 1990-07-26 | 1991-07-02 | Method for increasing the fault security by risk signal systems |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0468234B1 (en) |
| AT (1) | ATE143519T1 (en) |
| DE (1) | DE59108219D1 (en) |
| ES (1) | ES2091265T3 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7533517B2 (en) * | 2005-04-14 | 2009-05-19 | Snecma | Exhaust nozzle for an engine of a flying craft |
| US7535687B2 (en) | 2006-04-13 | 2009-05-19 | Ge Security, Inc. | Alarm system sensor topology apparatus and method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CH664637A5 (en) * | 1982-04-28 | 1988-03-15 | Cerberus Ag | METHOD FOR TRANSMITTING MEASURED VALUES IN A MONITORING SYSTEM. |
-
1991
- 1991-07-02 DE DE59108219T patent/DE59108219D1/en not_active Expired - Fee Related
- 1991-07-02 EP EP91110971A patent/EP0468234B1/en not_active Expired - Lifetime
- 1991-07-02 ES ES91110971T patent/ES2091265T3/en not_active Expired - Lifetime
- 1991-07-02 AT AT91110971T patent/ATE143519T1/en not_active IP Right Cessation
Also Published As
| Publication number | Publication date |
|---|---|
| ES2091265T3 (en) | 1996-11-01 |
| DE59108219D1 (en) | 1996-10-31 |
| ATE143519T1 (en) | 1996-10-15 |
| EP0468234A3 (en) | 1992-12-09 |
| EP0468234A2 (en) | 1992-01-29 |
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