GB2447122A - Monitoring device for a two wire line annunciator system - Google Patents
Monitoring device for a two wire line annunciator system Download PDFInfo
- Publication number
- GB2447122A GB2447122A GB0802863A GB0802863A GB2447122A GB 2447122 A GB2447122 A GB 2447122A GB 0802863 A GB0802863 A GB 0802863A GB 0802863 A GB0802863 A GB 0802863A GB 2447122 A GB2447122 A GB 2447122A
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- United Kingdom
- Prior art keywords
- test signal
- wire line
- monitoring device
- signal
- evaluation
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- 238000012806 monitoring device Methods 0.000 title claims abstract description 31
- 238000012360 testing method Methods 0.000 claims abstract description 69
- 238000011156 evaluation Methods 0.000 claims abstract description 23
- 238000002347 injection Methods 0.000 claims abstract description 16
- 239000007924 injection Substances 0.000 claims abstract description 16
- 238000000605 extraction Methods 0.000 claims abstract description 14
- 238000012544 monitoring process Methods 0.000 claims description 13
- 230000009467 reduction Effects 0.000 claims description 7
- 238000004891 communication Methods 0.000 claims description 6
- 230000005540 biological transmission Effects 0.000 claims description 4
- 238000001914 filtration Methods 0.000 claims description 3
- 230000001939 inductive effect Effects 0.000 claims description 2
- 230000006870 function Effects 0.000 description 9
- 230000008859 change Effects 0.000 description 8
- 230000007257 malfunction Effects 0.000 description 6
- 238000001514 detection method Methods 0.000 description 5
- 230000006866 deterioration Effects 0.000 description 5
- 230000000750 progressive effect Effects 0.000 description 4
- 238000013209 evaluation strategy Methods 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000001771 impaired effect Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Classifications
-
- 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
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B21/00—Alarms responsive to a single specified undesired or abnormal condition and not otherwise provided for
- G08B21/18—Status alarms
- G08B21/187—Machine fault alarms
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B29/00—Checking or monitoring of signalling or alarm systems; Prevention or correction of operating errors, e.g. preventing unauthorised operation
- G08B29/02—Monitoring continuously signalling or alarm systems
- G08B29/10—Monitoring of the annunciator circuits
-
- 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
- G08B29/12—Checking intermittently signalling or alarm systems
- G08B29/123—Checking intermittently signalling or alarm systems of line circuits
-
- 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
- G08B29/12—Checking intermittently signalling or alarm systems
- G08B29/126—Checking intermittently signalling or alarm systems of annunciator circuits
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Computer Security & Cryptography (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Testing Of Short-Circuits, Discontinuities, Leakage, Or Incorrect Line Connections (AREA)
Abstract
A monitoring device for a two-wire line 7, 9, in which a voltage source 2 connected to at least one functional element 3, 4, 5 such that a useful signal is transmitted vice comprises an injection device 12 for injecting a test signal into the two-wire line 7, 9 an extraction device 13 for extracting the test signal, and an evaluation device 14 for evaluating the extracted test signal and deducing the state of the two-wire line, where the test signal has an alternating current and/or alternating voltage component, preferably with a sinusoidal or triangular wave pattern. The maximum frequency distribution of the useful signal is preferably less than that of the test signal.
Description
Description Title
Monitoring device for a two-wire line, hazard annunciator system comprising the monitoring device
Prior art
The invention relates to a monitoring device for a two-wire line, wherein a voltage source is connected in circuit to at least one functional element via the two-wire line, such that a useful signal is transmitted and/or can be transmitted via the two-wire line, said monitoring device comprising an injection device for injecting a test signal into the two-wire line at the start of a test portion of the two-wire line, comprising an extraction device for extracting the test signal at the end of the test portion, and comprising an evaluation device for evaluating the extracted test signal, a state of the two-wire line being deduced by means of the evaluation.
Public or private buildings, industrial plants, railway stations, airports and the like are usually equipped with hazard annunciator systems which allow visitors to these places to actuate, in an emergency, a signal which, for example, is routed to a main monitoring station, where it is processed further. Further possible functions of the hazard annunciator system consist in indicating hazards, emergencies or escape routes to the visitors by means of optical, acoustic or haptic signals. In order to ensure faultless operation of the hazard annunciator systems, in hazard annunciator engineering and in safety engineering the regulations to be observed are continuously adapted to the knowledge ensuing from the operation of the hazard annunciator systems. One requirement in the regulations relates to the detection of changes of state of lines of the hazard annunciator systems, this being before these changes of state can result in malfunctions of the hazard annunciator systems.
Terms meaning "creeping short" and "creeping open", known from the Anglo-Saxon language area, have been introduced into the German language as terms for possible changes of state of the lines. In the specialist domain, the term creeping short is understood to be a slowly progressive reduction of the resistance between two cores, e.g. of two-wire lines, and the term creeping open is understood to be a slowly progressive increase in the line resistance of one, two or more cores, e.g. of the two-wire lines. The cause of these slow changes may be found to be environmental influences, mainly moisture and gases, which result in oxidation of contact points of the copper wires or in reduction of the isolating properties between the copper lines.
A monitoring system that is possibly usable for detecting these changes of state of lines is proposed in the published patent application DE 19538754 A 1, which system relates to a method for monitoring primary lines, and which probably constitutes the nearest prior art. The printed publication describes a method for monitoring a primary line in a hazard annunciator system, the primary line having an indicating resistor and a reference resistor, which are connected in series. Possible malfunctions of the primary line are discovered by evaluating the quotient from the voltage drop at the reference resistor and from the voltage drop on the primary line or at the indicating resistor.
Disclosure of the invention
According to the invention, there is proposed both a monitoring device for a two-wire line, having the features of Claim 1, and a hazard annunciator system having the features of Claim 13. Preferred or advantageous embodiments of the invention are disclosed by the dependent claims, the following description and/or the appended figure.
The proposed monitoring device is suitable and/or designed for a two-wire line of a monitoring system. The two-wire line is preferably realized as a parallel line having two cores, the two cores of the two-wire line being mechanically connected to each other over the entire length and/or realized as a twisted two-wire line, the two cores of the two-wire line being twisted together and/or realized as a shielded two-wire line, the two cores of the two-wire line being shielded by a tube-like, conductive covering.
The two-wire line serves to connect a voltage source to at least one functional element, the voltage source providing a useful signal which is preferably realized as a direct voltage for supplying the functional element, as a communication signal for the functional element and/or for the output of a monitoring signal for the functional element. The useful signal is transmitted between the voltage source and the functional element via precisely the two cores of the two-wire line or via at least the two cores of the two-wire line.
The monitoring device comprises an injection device for injecting a test signal into the two-wire line, in particular into a first core of the two-wire line, the injection device being so arranged that the test signal is injected at the start of a test portion of the two-wire line. In addition, the monitoring device comprises an extraction device, which is arranged for extracting the test signal at an end of the test portion of the two-wi-re line, in particular on a second core of the two-wire line.
An evaluation device serves to evaluate the extracted test signal, a malfunction of the two-wire line being deduced by means of the evaluation. A malfunction also comprises, in particular, the cases of creeping short and/or of creeping open, for the definition of which reference is made to, for
example, the introduction.
According to the invention, provision is made whereby the test signal has an alternating current component and/or an alternating voltage component. The test signal can thus show a signal characteristic which varies as a function of time, the current amplitude or voltage amplitude having a sign change in the time characteristic; in particular, the test signal is symmetrical in form, such that that component of the test signal which has the one polarity is the same as that component of the test signal which has the other polarity. In the case of an alternative embodiment, the test signal has an offset, onto which the alternating current component or the alternating voltage component is modulated.
The invention proceeds from the consideration that the detection of, in particular, deteriorationS in the state of two-wire lines in hazard annunciator systems is liable to error, since often the electric power supply, communication signals or monitoring signals is/are also routed via these lines in a combined application. The resultant time changes in voltage amplitudes and current amplitudes in the two-wire lines makes it almost impossible to attribute the cause of a creeping short, for example on the basis of an increase in the supply current or supply voltage, since the increase could just as well result from a change in the switching state of a functional element. Detection of the cause of a creeping open on the basis of a reduction in current or voltage is equally unreliable. The detection is also made more difficult by the fact that, upon the occurrence of creeping changes, there will initially be little change in the operational capability of the hazard annunciator system. Whether a change in the supply current or supply voltage is noticeable at all, also depends greatly on, for example, the location at which the creeping change occurs.
There is proposed, in the scope of the invention, a solution which constitutes a basis for early detection of the described deviations from the desired state of two-wire lines, this being without interaction with the current supply or voltage supply of the functional elements supplied by means of the two-wire line. The invention exploits the fact that the useful signals operate with a switching frequency in a low-frequency range, whereas the test signal has an alternating current component or alternating voltage component which is located in a higher-frequency range of the frequency spectrum. The result of this division of the two signals into two different, in particular, non-overlapping or only slightly overlapping frequency bands is that the test signal can easily be filtered out or attenuated before the functional elements and, in the case of the extraction device, only the test signal, and not the useful signal, is extracted.
In the case of a preferred embodiment, the maximum of the frequency distribution of the useful signal is located at a lesser frequency than the maximum of the frequency distribution of the test signal. It is thus possible for the test signal to be easily separated from the useful signal or other surrounding signal through the use of a filter having a limit frequency located between the two maxima.
It is particularly preferred if the useful signal is realized as a direct voltage signal for voltage supply, for monitoring and/or for communication. In this connection, preferably, direct voltage signal is to be understood as a signal which may exhibit change as a function of time, e.g. the change from one switching state to a subsequent switching state, but which, preferably, does so without changing polarity.
In general, the alternating current component or alternating voltage component of the test signal can be realized in any manner, thus, for example, as noise, in particular static or binary noise. It is preferred, however, that the test signal have a regular, in particular sinusoidal or triangle-shaped, amplitude characteristic as a function of time. Such an amplitude characteristic makes it easier for the useful signal and the test signal to be separated from each other with the use of simple electronic components such as, for example, inductors or coils.
In the case of a particularly preferred embodiment, the injection device and/or the extraction device is/are realized for the contactiess, inductive, galvanically isolated and/or potential-free transmission of the test signal. In particular, the insulation or the like of the two-wire lines must not be damaged in this case, so as to preclude the risk of the functioning of the two-wire line being impaired by the installation of the monitoring device.
In the case of a preferred embodiment, the injection device is arranged at a first connection of the two-wire line, in particular, of one of the cores of the two-wire line, at the voltage source or in immediate proximity thereto, in particular, without interposition of further functional elements. Alternatively, or in addition, the extraction device is connected in circuit to a second connection of the two-wire line, in particular, to another core of the two-wire line, at the voltage source, in particular, in the same way as the injection device. With this embodiment, it is ensured that the entire course of the two-wire line is realized as a test portion and is monitored. In addition, it is easy for the monitoring device to be arranged centrally at the voltage source and/or in a common housing with the voltage source, such that, for example, laying of additional lines for the monitoring device is unnecessary.
In the case of an expedient development of the invention, provision is made whereby a terminating resistor is connected in circuit in parallel to the at least one functional element, said terminating resistor preferably being designed to close an alternating current circuit between the injection device and the extraction device.
This terminating resistor ensures, in particular, that there is a defined flow of alternating current through the alternating current circuit. It is preferably a prerequisite in this case that the internal resistance of the voltage source constitutes a short-circuit or approximately a short-circuit for that frequency of the alternating current component which is used.
In the case of a comparatively complex embodiment of the invention, the evaluation is effected by comparison of the extracted test signal and/or its characteristic quantities with the injected test signal and/or its characteristic quantities. Provision may thereby be made, for example, whereby a transmission function is calculated for the test portion and changes in the transmission function are evaluated, whereby a correlation is calculated, or similar.
In the case of a comparatively simple, and therefore inexpensively realizable, alternative, the evaluation is effected by comparison of the value of the current flow and/or voltage of the extracted test signal in the current state with an initial value of the initial current flow and/or of the voltage in the case of the intact and tested monitoring system. For example, the initial value is stored as a digitized quantity in an appropriate storage medium, comparisons between the current value and the stored value being performed continually during operation.
It is thus possible, in principle, to perform the evaluation of the extracted test signal by means of an absolute evaluation or a relative evaluation.
In the case of the last-named alternative, in particular, it is preferred that the evaluation device have an evaluation logic, for example realized as software, wherein a creeping open is deduced in the case of reduction of the value of the current flow and/or of the voltage of the extracted test signal and/or a creeping short is deduced in the case of an increase in the value of the current flow and/or of the voltage of the extracted test signal. The nature of the line variation can thus be determined from the deviation of the current flow and/or of the voltage, and appropriate service measures initiated. The evaluation is preferably effected in a computing unit, e.g. a microprocessor, that is normally used and/or is already present in the monitoring system and is expanded by one functionality with the monitoring device.
In the case of a practical realization of the monitoring device, a filter for filtering out or at least for attenuating the test signal is connected in circuit before the one functional element, some functional elements or each functional element. In the simplest, and therefore preferred, case, the filter is realized as an inductor, in particular a coil, the filter being so designed that it has a high impedance or a local and/or global impedance maximum for the frequency of the alternating current component and/or of the alternating voltage component of the test signal.
A further subject-matter of the invention relates to a hazard annunciator system comprising a two-wire line having the feature of Claim 13, said system having a monitoring device, such as that just described and according to the preceding claims, for monitoring the two-wire line. The hazard annunciator system is preferably of the same design as the hazard annunciator system described above, the functional elements being realized, for example, as annunciators, in particular manually operated annunciators, fire annunciators, emergency annunciators, sensors, in particular for fire, smoke, water or noise, or as indicators, in particular for emergency exits. Realization as an alarm system is also within the scope of the invention.
Brief description of the drawings
Further features, advantages and effect of the invention are disclosed by the following description and the figure of a preferred exemplary embodiment of the invention, wherein: Figure 1 shows a schematic circuit diagram of a hazard annunciator system as an exemplary embodiment of the invention.
Embodiment(s) of the invention Figure 1 shows a schematic block diagram of a hazard annunciator system 1 realized, for example, as a fire annunciator system, police emergency-call system, alarm system or the like.
The hazard annunciator system 1 has a voltage source 2, which supplies voltage or communication signals to functional elements 3, 4 and 5. The functional elements 3, 4 and 5 may be realized as annunciators, indicator units or sensor units. The voltage source 2 is realized as a direct voltage source, such that voltage levels that vary as a function of time occur only as a result of changes in the switching states of the functional elements 3, 4 or 5 or as a result of the communication signals. The voltage source 2 has an output 6, which is connected to the functional elements 3, 4 and 5 via a first core 7. In addition, the voltage source 2 has an input 8, which is likewise connected to the functional elements 3, 4, 5, via a second core 9, such that these are connected in parallel to each other. The cores 7 and 9 are preferably realized together as a two-wire line.
The components of the hazard annunciator system 1 represented thus far are sufficient for a function. In operation, however, deteriorations of the two-wire line may occur, thus in particular, of the cores 7 and 9. A possible source of deterioration is that of so-called creeping opens, which are visualized by the broken line 10 in the first core 7, a creeping open being a slowly progressive increase in the line resistance. Obviously, creeping opens can occur in one of the two cores 7 or 9 or, also, in both. Another possible fault source, which is usually difficult to detect, is the so-called creeping short, which is visualized by a short-circuit line 11 in Figure 1, a creeping short being understood to be a slowly progressive reduction of the resistance between the two cores 7 and 9. Obviously, apart from the creeping variations, sudden changes can also result in a functional failure of the hazard annunciator system 1.
For the purpose of detecting such functional deterioratiOns or further functional deteriorations of the two-wire line or of the cores 7 and 9, an injection device 12 is arranged in the region of the output 6, which injection device inductively and contactiessly injects into the first core 7 a test signal which is realized either as an alternating voltage signal or alternating current signal or at least has an alternating voltage component or alternating current component. The injection device 12 is realized, for example, as a matching transformer, a matching transformer constituting a transformer that is not designed primarily to transmit energy, but to transmit information. The test signal is realized, exemplarily, as a sinusoidal or triangle-shaped signal. In addition, an extraction device 13, which likewise may be realized as a matching transformer, is arranged in the region of the output 8. By means of this extraction device 13, the test signal, which meanwhile has passed through a test portion of the two-wire line located between the injection device 12 and the extraction device, is extracted and supplied to an evaluation unit 14. In order that the test signal cannot exert a disturbing influence on the functional elements 3, 4 and 5, a respective inductor 15, 16 and 17 is connected serially before the functional elements 3, 4 and 5, the inductors being so tuned that they have a high impedance for that frequency of the test signal which is used.
Alternatively, the inductors 15, 16 and 17 can be connected together in a common inductor (not shown) In order to ensure a defined flow of alternating current through the test portion, a terminating resistor 18 is provided, connected in parallel to the assemblies that consist, respectively, of a functional element 3, 4 or 5 and one of the inductors 15, 16 or 17, the terminating resistor 18 closing the alternating current path between the injection device 12 and the extraction device 13.
The extracted test signal is investigated by the evaluation device 14, with various evaluation strategies being conceivable: a first possible evaluation strategy consists in the extracted test signal being compared with the injected test signal. Another possible evaluation strategy consists in the amplitude of the extracted test signal being compared with a stored amplitude, and a deterioration or malfunction of the cores 7 or 9 being deduced in the case of change in the amplitude. Classification of the impaired function or malfunction can be effected, for example, such that a creeping open is deduced in the case of a reduction of the amplitude of the extracted test signal, and a creeping short is deduced in the case of an increase in the amplitude of the extracted test signal.
The evaluation device is optionally designed to emit a warning signal following the evaluation or classification.
Claims (14)
- Cia irns 1. Monitoring device for a two-wire line (7, 9), wherein avoltage source (2) is connected in circuit to at least one functional element (3, 4, 5) via the two-wire line (7, 9), such that a useful signal is transmitted and/or can be transmitted via the two-wire line (7, 9), said monitoring device comprising an injection device (12) for injecting a test signal into the two-wire line (7, 9) at the start of a test portion of the two-wire line (7, 9), comprising an extraction device (13) for extracting the test signal at the end of the test portion, and comprising an evaluation device (14) for evaluating the extracted test signal, a state of the two-wire line (7, 9) being deduced by means of the evaluation, characterized in that the test signal has an alternating current component and/or alternating voltage component.
- 2. Monitoring device according to either of Claims 1 or 2, characterized in that the maximum of the frequency distribution of the useful signal is less than the maximum of the frequency distribution of the test signal.
- 3. Monitoring device according to either of Claims 1 or 2, characterized in that the useful signal is realized as a direct voltage signal for voltage supply, for monitoring and/or for communication.
- 4. Monitoring device according to any one of the preceding claims, characterized in that the test signal has a sinusoidal or triangle-shaped characteristic as a function of time.
- 5. Monitoring device according to any one of the preceding claims, characterized in that the injection device (12) and/or the extraction device (13) is/are realized for the inductive and/or contactiess and/or potential-free and/or galvanically isolated transmission of the test signal.
- 6. Monitoring device according to any one of the preceding claims, characterized in that the injection device (12) is connected in circuit to a first connection (6) of the two-wire line (7, 9) at the voltage source (2) and/or the extraction device (13) is connected in circuit to a second connection (8) of the two-wire line (7, 9) at the voltage source.
- 7. Monitoring device according to any one of the preceding claims, characterized in that a terminating resistor (18) is connected in circuit in parallel to the at least one functional element (3, 4, 5)
- 8. Monitoring device according to any one of the preceding claims, characterized in that the evaluation is effected by comparison of the extracted test signal and/or its characteristic quantities with the injected test signal and/or its characteristic quantities.
- 9. Monitoring device according to any one of the preceding claims, characterized in that the evaluation is effected by comparison of the current flow of the extracted test signal with a reference value.
- 10. Monitoring device according to any one of the preceding claims, characterized in that the evaluation device has an evaluation logic, wherein a creeping open is deduced in the case of reduction of the current flow and/or a creeping short is deduced in the case of an increase in the current flow.
- 11. Monitoring device according to any one of the preceding claims, characterized in that a filter for filtering out or attenuating the test signal is connected in circuit before the functional element (3, 4, 5), some functional elements or each functional element.
- 12. Monitoring device according to any one of the preceding claims, characterized in that an inductor (15, 16, 17) for filtering out or attenuating the test signal is connected in circuit before the functional element (3, 4, 5), some functional elements or each functional element, the alternating current resistance of the inductor being matched to the frequency of the test signal.
- 13. A monitoring device for a two-wire line, substantially as herein described with reference to the accompanying drawings.
- 14. Hazard annunciator system comprising a two-wire line (7, 9), characterized in that a monitoring device according to any one of the preceding claims is provided for monitoring the two-wire line (7, 9)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102007008263A DE102007008263A1 (en) | 2007-02-20 | 2007-02-20 | Monitoring device for a two-wire line, hazard detection system with the monitoring device |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0802863D0 GB0802863D0 (en) | 2008-03-26 |
| GB2447122A true GB2447122A (en) | 2008-09-03 |
| GB2447122B GB2447122B (en) | 2009-12-23 |
Family
ID=39271811
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0802863A Expired - Fee Related GB2447122B (en) | 2007-02-20 | 2008-02-15 | Monitoring device for a two-wire line, hazard annunciator system comprising the monitoring device |
Country Status (3)
| Country | Link |
|---|---|
| CN (1) | CN101251949A (en) |
| DE (1) | DE102007008263A1 (en) |
| GB (1) | GB2447122B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8456315B2 (en) | 2008-04-28 | 2013-06-04 | Robert Bosch Gmbh | Monitoring device for functionally monitoring reporting system, reporting system, and method for monitoring |
| US10690550B2 (en) | 2016-08-15 | 2020-06-23 | Leoni Kabel Gmbh | Method for monitoring a line for unchanged ambient conditions and measuring arrangement for monitoring a line for changed ambient conditions |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108831129B (en) * | 2018-08-28 | 2024-02-06 | 中车兰州机车有限公司 | Testing device for locomotive roof high-voltage alarm device |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0284217A1 (en) * | 1987-02-27 | 1988-09-28 | BARNES, Austen Bernard | Malfunction detector |
| DE19538754A1 (en) * | 1995-10-18 | 1997-04-24 | Bosch Gmbh Robert | Primary line monitoring method for alarm system |
| US5966069A (en) * | 1998-03-19 | 1999-10-12 | Prescolite-Moldcast Lighting Company | Exit sign self-testing system |
-
2007
- 2007-02-20 DE DE102007008263A patent/DE102007008263A1/en active Pending
-
2008
- 2008-02-15 GB GB0802863A patent/GB2447122B/en not_active Expired - Fee Related
- 2008-02-20 CN CNA2008100812210A patent/CN101251949A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0284217A1 (en) * | 1987-02-27 | 1988-09-28 | BARNES, Austen Bernard | Malfunction detector |
| DE19538754A1 (en) * | 1995-10-18 | 1997-04-24 | Bosch Gmbh Robert | Primary line monitoring method for alarm system |
| US5966069A (en) * | 1998-03-19 | 1999-10-12 | Prescolite-Moldcast Lighting Company | Exit sign self-testing system |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8456315B2 (en) | 2008-04-28 | 2013-06-04 | Robert Bosch Gmbh | Monitoring device for functionally monitoring reporting system, reporting system, and method for monitoring |
| US10690550B2 (en) | 2016-08-15 | 2020-06-23 | Leoni Kabel Gmbh | Method for monitoring a line for unchanged ambient conditions and measuring arrangement for monitoring a line for changed ambient conditions |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2447122B (en) | 2009-12-23 |
| DE102007008263A1 (en) | 2008-08-21 |
| GB0802863D0 (en) | 2008-03-26 |
| CN101251949A (en) | 2008-08-27 |
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| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20210215 |