AU2013221964A1

AU2013221964A1 - Emergency/safety lighting system and controlling method therefor

Info

Publication number: AU2013221964A1
Application number: AU2013221964A
Authority: AU
Inventors: Jurgen Prasuhn
Original assignee: CEAG Notlichtsysteme GmbH
Current assignee: CEAG Notlichtsysteme GmbH
Priority date: 2012-08-31
Filing date: 2013-08-29
Publication date: 2014-03-20
Anticipated expiration: 2033-08-29
Also published as: DE102012017360A1; EP2704332B1; AU2013221964B2; EP2704332A3; EP2704332A2; PL2704332T3

Abstract

Abstract An emergency/safety lighting system (1) comprises at least one central control unit (2), an AC and DC power supply (3, 4), a switch-over device (5) switchable between these two power supplies (3, 4), and a number of consumers (7) connected to the central control unit (2) by a power supply line (6). In order to be able to transmit information signals to the consumer (7) in a reliable and simple manner regardless of the type of supply voltage, the central control unit (2) comprises a polarity-reversing device (8) assigned at least to the DC power supply (4). Same can be controlled for the in particular binary encoding of an information signal by means of a sequence of polarity reversals of the supply voltage provided by the power supply (4). The encoded information signal can be transmitted by the supply voltage from the central control unit (2) through the power supply line (6) to at least one consumer (7). The circuit part connected upstream of the consumer(s) (7) and having an additional rectifier allows by means of a suited encoding by polarity-reversing operations a transmission and decoding of information although capacitances accompanied by usually high recharging losses and high EMC-critical interference voltages resulting therefrom are used in the downstream consumer supply apparatus. Figure for the abstract: Fig. 1 7782284_1 m CV Q C 0m)C Co- - -- - - - - - - - - Im [-- CNJj cco ai "I -- - - - - -

Description

1 Emergency/safety lighting system and controlling method therefor Technical Field The invention relates to an emergency/safety lighting system and a corresponding controlling method therefor. The emergency/safety lighting system comprises at least one central control unit, an AC and DC power supply, a switch-over device switchable between these two power supplies, and a number of consumers connected in parallel to the central control unit by a power supply line. Background Corresponding emergency/safety lighting systems and associated methods are known, for example, from DE 195 29751 Al, DE 198 14 366 Al, EP 1 170 849 B1 or EP 2 194 762 Al. The DE 195 29751 Al document, for example, relates to a method for the central monitoring of the function of electrical consumers connected in parallel to an AC voltage network as well as a corresponding apparatus for performing the method. A function monitoring of this type can imply that the functionality or the on-state, or both, at the consumer site is detected and transmitted as a status signal to a central monitoring device. The DE 198 14 366 Al document describes a method for controlling at least one electrical consumer connected to a controlling apparatus by electrical supply lines. A control signal is transmitted through the electrical supply lines to the electrical consumer. To encode an information the supply voltage is varied, respectively modified in such a way that same is altered with respect to its maximum value or interrupted for a certain time period. By the sequence of the maximum value changes, respectively interruptions of the supply voltage an encoded information signal is obtained, which is detected by the consumer and converted into a corresponding binary signal. In the EP 1 170 849 B1 document a method and a corresponding switching arrangement for performing the method are described, whereby a controlling apparatus is connected to an electrical consumer by electrical supply lines. A control signal is transmitted through the electrical supply lines, and the controlling apparatus changes a supply voltage transmitted through the supply line to the consumer in terms of the voltage value thereof, or interrupts the voltage, to encode the control signal. 7782284_1 2 The EP 2 194 762 Al document describes not only a periodic transmission of monitoring and/or test queries and corresponding monitoring and/or test answers between the central station and a monitoring and control module of a light, but also a substantially continuous monitoring of the light in respect of at least one light parameter and generating a corresponding light status at least in the case of an impermissible light parameter. The DE 197 25 710 Al documents discloses a method and an apparatus for the power and data transmission on common lines. The transmission of data is realized bidirectionally. A specific transmission mode, as compared to a supply mode, is provided for the transmission of the data. During the transmission of a data word the respective system is in the transmission mode and between the data words in the supply mode. The DE 290 4 849 Al document discloses a method for transmitting information and an apparatus for performing this method. An information transmitter feeds information into effect supply lines for several connected apparatus. The output current of the transmitter is interrupted for a certain time period. This causes a voltage drop. The connected units are capable of detecting this irregularity in the voltage characteristic, so that the transmitter is able to transmit information to the other units by an interruption of the current in a half-wave for a short time. As a rule, there will be a phase shift between the voltage characteristic and the flow of the current, which is dependent on capacitances and inductances provided in the circuit. The DE 196 03 680 C1 document describes a method for the selective switching and controlling of consumers in an alternating current circuit. One single oscillation with two half-waves of an alternating voltage is used to transmit information for switching and controlling to a consumer. To this end, the phase position of each half-wave of an oscillation is changed. Using only one single oscillation is said to reduce the time needed for the data transmission. An information in respect of the selection of an individual or all consumers is contained in the phase cutting period of a first half-wave of the single oscillation, while an information about the power consumption is contained in the phase cutting period of the other half-wave of this single oscillation. The load in the electric circuit is turned off during the period of the respective data transmission. The DE 3 828 271 Al document discloses a method for the serial transmission of telegrams, whereby each telegram is subdivided into words, and the transmission of the first word starts with a starting pulse and one pulse is then transmitted per word, the time 7782284_1 3 interval to the preceding pulse corresponding to the valence of the word. Thus, a prioritization of the communication is obtained. The DE 195 48 744 document describes a signaling and intercommunication system for use in building technology. Various terminal devices are connected by a two-wire bus to a central controlling apparatus. Each terminal device includes a command transmit and receive circuit which is comprised of a level switch and a level detector. A transmission command is generated by a microprocessor such that the level switch is closed and opened in quick succession in accordance with the desired command protocol. As a consequence thereof a higher current flows via the bus, and thus through a load resistance in the central controlling unit that is shared by all devices. This thus results in an increased voltage drop at the load resistance so that the remaining bus voltage for all other devices is reduced. The central controlling apparatus adds an address of the addressed device to the command protocol, so that this addressed device can identify itself by means of its level detector and evaluate the command in a corresponding logic circuit. If the load resistance is bypassed, no commands can be sent by means of current modulation. The DE 28 35 594 document discloses a method for transmitting information and a corresponding apparatus. The apparatus comprises a controlling device and a number of units connected in parallel. Voltage or current are interrupted for the detection of a command signal whereby a half-wave pattern with interruptions is generated, meaning that individual positive and/or negative half-waves are removed from the current or voltage signal. In this alternative it is possible to determine the number of the complete half-waves between two missing half-waves. This number is compared to a stored number and, in case of agreement, interpreted as a corresponding command. The present invention and the cited documents describe an emergency/safety lighting system having a plurality of consumers, such as safety lights, emergency sign lights or other lights. Such systems are subject to a number of electrotechnical regulations and regulations pertaining to lighting engineering, such as the standards DIN VDE 0108, EN 50172, IEC 60364-5-56 or DIN EN 1838. These standards describe how the various lights of the system are supplied, for example, in an emergency, which controls are necessary to ensure the functionality or monitor the operation. Furthermore, test results are recorded and specific fire protection requirements are defined. In particular, also a central controllability of all those special lights of an emergency/safety lighting system is 7782284_1 4 necessary as the direct controlling or influencing, for example by means of an ordinary light switch in the supply line, is not permissible for safety reasons because the operation of the emergency/safety lights as intended is not guaranteed in the event of a power failure. Instead, the controlling and monitoring of a plurality of such lights is always accomplished centrally. In doing so, it has proved to be particularly advantageous if no additional data lines are necessary for such a controlling/monitoring, e.g. between a central control unit and the consumers. Instead, the controlling and monitoring is realized by means of corresponding information signals which are transmitted through the power supply lines. To avoid the need of modulating additional signals, for example, to the supply voltage in addition to the supply voltage it has furthermore proved to be advantageous if the respective supply voltage is being influenced directly to transmit information signals, see for example DE 198 13 366 A1 or EP 1 170 849 B1. In the above-described methods and apparatus a generation of the information signals was, as a rule, realized by means of encoded phase cuttings of the alternating mains voltage, i.e. the AC supply voltage. Zero-crossings of the supply voltage were used to trigger the phase cuttings. Summary Aspects of the present disclosure provide transmission of respective information signals to the consumer in a reliable and simple manner regardless of the type of supply voltage. According to an aspect of the present disclosure, there is provided an emergency/safety lighting system comprising at least one central control unit, an AC and DC power supply, a switch-over device switchable between these two power supplies, and a number of consumers connected to the central control unit by a power supply line, wherein the central control unit comprises a polarity-reversing device assigned at least to the DC power supply, which can be controlled for the in particular binary encoding of an information signal by means of a sequence of polarity reversals of the supply voltage provided by the power supply, which encoded information signal can be transmitted by the supply voltage from the central control unit through the power supply line to at least one consumer. According to an aspect of the present disclosure, there is provided a method for 7782284_1 5 controlling and/or monitoring an emergency/safety lighting system comprising at least one central control unit and consumers connected to same by a power supply line, wherein an in particular binary-coded information signal is transmitted as part of a supply voltage from the central control unit through the power supply line to at least one consumer, which central control unit is selectively connected to an AC and DC power supply, wherein an encoding of the information signal is realized by a sequence of polarity reversals of the supply voltage by means of a polarity-reversing device of the central control unit. According to an aspect of the present disclosure, the above-described emergency/safety lighting system is provided with the central control unit comprises a polarity-reversing device assigned at least to the DC power supply, which can be controlled for the in particular binary encoding of an information signal by means of a sequence of polarity reversals of the supply voltage provided by the power supply, which encoded information signal can be transmitted by the supply voltage from the central control unit through the power supply line to at least one consumer. Corresponding information signals allow, for example, to influence one consumer, or also all consumers connected to the central control unit with regard to their status. This may comprise a switching on or off, dimming by a certain percentage or the like. The switch over device serves in a simple manner to reverse the polarity of the DC supply voltage available at the input thereof, so that the polarity of the voltage supplied by the switch-over device is respectively reversed. These polarity reversals are subject to a certain time sequence, with an encoded information signal being included in this time sequence. The consumer or an evaluation and control module connected upstream of the consumer detects the polarity reversals, and evaluates them in order to restore the encoded information signal. The encoded information signal corresponds to a binary bit pattern. There are different alternatives to arrange the polarity-reversing device in the central control unit. For example, the polarity-reversing device may be arranged between the DC power supply and the switch-over device. The switch-over device serves to switch between the DC and AC power supply. By the corresponding arrangement of the polarity reversing device same can be applied only for DC supply voltage. Another arrangement can be obtained if the polarity-reversing device is arranged between the switch-over device and the power supply line. That is, in this case the polarity reversing device will possibly be utilized only if a DC supply voltage is available. If an AC 7782284_1 6 supply voltage is available the polarity-reversing device may be switched to be ineffective or used in a fixed state, respectively. This switching of the polarity-reversing device to have no effect may also be advantageous in the case where no information is transmitted so as to avoid losses at the switching units of the polarity-reversing device. To monitor the supply voltage and/or current of the AC or DC power supply in the central control unit, the central control unit may comprise a current/voltage detection device. This device can detect, for example, that no AC supply voltage is present and then induce a switching to DC supply voltage by means of the switch-over device. As a rule, the AC power supply is the mains power supply, while the DC power supply is formed by a group battery system, a central battery system or the like. As a rule, an electric circuit to consumers behind a last overcurrent protection device in a distributor of a current supply system is defined as a final circuit. According to aspects of the present disclosure it is possible in this regard that a polarity-reversing device is assigned at least to each final circuit. Such a final circuit is subject to various conditions, e.g. that no switches or switching elements are permitted. Where required, only switches for the central and group-wise switching are permitted. Furthermore, it is regulated that not more than 20 consumers, and in particular lights, are connected in the final circuit of the safety lighting system. This means, according to the feature described, that a polarity-reversing device may control all lights, respectively consumers of a final circuit. There are various possibilities for reversing a supply voltage polarity. According to aspects of the present disclosure the polarity-reversing device may comprise, for example, a full bridge arrangement of switching units. The switching units can be semiconductor switches which are interconnected in a full bridge arrangement in a corresponding manner. Also electromechanical switching units are possible, which usually require more space, have a greater amount of maintenance and are subject to greater wear, however. To allow an easy detection of the polarity reversal of the supply voltage in the consumer the consumer may comprise a polarity reversal detection device for the detection of 7782284_1 7 polarity reversals of the supply voltage. Depending on the type of the consumer or consumers it may be an advantage if the polarity reversals are detected in the current, respectively voltage, so that it is conceivable that the current and/or voltage of the supply voltage can be monitored by the polarity reversal detection device. The polarity reversal detection device may be part of a controlling/monitoring device which is assigned to the consumer. In this connection it is possible, for example, that the polarity reversal detection device detects only corresponding polarity reversals and generates a corresponding signal. A conversion of this signal into a binary information signal may be accomplished by another component of the controlling/monitoring device. Thus, it is conceivable, for example, that the controlling/monitoring device comprises a conversion device converting a sequence of polarity reversals into a binary information signal. The conversion device receives a signal from the polarity reversal detection device to mark the polarity reversals and generates from this signal the corresponding binary information signal which corresponds to the information signal originally encoded by the central control unit. The control signal can induce a corresponding controlling of the consumer, see above statements, such as switching on and off, dimming by a certain percentage and the like. Other controlling alternatives are possible as well, such as performing a test, requesting status information or the like. In order to be able to address in this connection a specific consumer, a group of consumers, or also all consumers, the information signal may include, in addition to the control information for the actual controlling of the consumer, an address information for selectively addressing each consumer, or for the group-wise addressing of a plurality of consumers. Of course, it is also possible that all consumers connected to the central control unit are addressed at the same time, for example, to switch all consumers on or off. To allow a corresponding controlling according to the present application of already existing consumers the controlling/monitoring device may be configured as a separate module connectable to the consumer or insertable into such a consumer. A corresponding information transmission in the case of an AC supply voltage can be accomplished, for example, in the manner described above according to the corresponding cited documents. This means that there is a possibility that in the case of an AC power supply a current/voltage varying device is provided for the binary encoding 7782284_1 8 of an information signal contained in the supply voltage and to be transmitted through the power supply line. This means, for example, that two different devices would be used depending on the power supply. It is also conceivable, however, that the polarity-reversing device is used as a current/voltage varying device for the AC power supply. The polarity-reversing device comprises corresponding switching units which may also be utilized as a current/voltage varying device for the AC power supply. That is, in an AC operation a controlling and, where applicable, also an addressing could be accomplished by the polarity-reversing device, by means of a sequence of phases with a voltage interruption and phases without a voltage interruption, depending on the information to be transmitted. Moreover, if necessary, the polarity-reversing device may also be employed such that it is virtually used as a rectifier in the case of an AC power supply, so that in an AC operation the communication with the consumers is not encoded by voltage interruptions or the like, but by a sequence of phases with rectification and phases without rectification dependent on the bit pattern. In the latter case the further advantage is obtained that no interruptions in the supply voltage occur in order to transmit the corresponding information signal to the consumer. To allow receiving corresponding feedbacks from one or each consumer by the central control unit the consumer may comprise a load device for influencing a load current. The corresponding influencing of the load current, respectively the corresponding voltage is detected and evaluated by the current/voltage detection device of the central control unit. In this connection it is furthermore conceivable that the influencing of the load current, respectively the corresponding voltage is formed of a number of load pulses to encode a return information signal. This means that the corresponding information transmission may likewise by realized in the reverse direction from the consumer to the central control unit, with corresponding time-sequential load pulses determining the encoded return information signal. In an emergency/safety lighting system the corresponding consumers are, for example, different lights, such as safety lights, emergency sign lights or also other lights. The corresponding system may also comprise other consumers, e.g. fire detectors, audible or 7782284_1 9 visual warning devices or the like. All of these can be controlled and monitored correspondingly. With a number of lights of the respective emergency/safety lighting system it is an advantage if these lights comprise an electric or electronic ballast. Such a ballast, too, being in particular a part of the consumer, can be controlled and monitored by the central control unit. For example, an electronic ballast may realize the dimming of a light in an easy manner. To prevent a malfunction of the system in particular by electrical or electronic influences the controlling/monitoring device may comprise an overvoltage protection device upstream of the rectifier. Respective devices can also be arranged in the central control unit. In order to allow the direct influencing of the consumer by means of the controlling/monitoring device the controlling/monitoring device may comprise a controlling connection for controlling/monitoring a consumer controlling device, such as a ballast or the like. This means that the controlling/monitoring device controls, for example, the ballast for dimming a light by means of the decoded information signal that was restored from the polarity reversals of the supply voltage. According to the method a respective controlling and/or monitoring of consumers connected to a central control unit by a power supply line is realized analogously. With respect to the information signal it is noted that same transmits less digital information if only control information are transmitted, as compared to the case where control information and address information are transmitted simultaneously. This means that when address and control information are transmitted the generated bit pattern is usually longer, as compared to the case where only a control information is transmitted. Furthermore, it is possible that the address information is transmitted in advance of the control information and independently of the latter, for example, to already select a consumer or a group of consumers to which the corresponding control information is then transmitted in a subsequent time interval. Of course, it is also possible to transmit both information, viz. control information and address information, in one information signal having a correspondingly long bit pattern. As a rule, the address information may, in this connection, be contained directly ahead of the control information in the information signal. 7782284_1 10 Summarizing, it is once again pointed out that, according to aspects of the present disclosure, a polarity reversal in particular of the DC supply voltage is realized in a time sequence dependent on a bit pattern which encodes a corresponding address and/or control information, so as to selectively address and control, in this manner, a number of consumers, individually or also in groups. Brief Description of the Drawings Advantageous exemplary embodiments of the invention will be explained in more detail below by means of the figures depicted in the drawing: In the drawing: Fig. 1 shows a schematic diagram of an emergency/safety lighting system according to the invention, comprising a plurality of consumers and a central control unit, Fig. 2 shows an embodiment of a polarity-reversing device as part of the central control unit of Fig. 1, Fig. 3 shows a schematic diagram of a consumer with an electronic ballast, Fig. 4 shows the consumer of Fig. 3 with a first embodiment of an associated controlling/monitoring device, Fig. 5 shows the consumer of Fig. 3 with a second embodiment of an associated controlling/monitoring device, and Fig. 6 shows schematic diagrams illustrating a DC supply voltage polarity-reversed multiple times and a generated bit pattern. Detailed Description Fig. 1 shows a schematic diagram of an embodiment of an emergency/safety lighting system 1 according to the invention. Same comprises at least one central control unit 2 and a plurality of consumers 7 connected to same by a power supply line 6. The 7782284_1 11 consumers 7 are, for example, safety lights, emergency sign lights, other lights or, in the appropriate case, fire detectors, audible or visual warning devices or the like. The consumers 7 are interconnected to the power supply line 6 in parallel. In the embodiment shown the power supply line 6 comprises two supply lines (the normally required protective conductor is not shown). The central control unit 2 serves, for example, to supply, control and monitor a final circuit in which, according to current standards, up to 20 consumers may be arranged. The central control unit 2 is connected to an AC power supply 3 and a DC power supply 4 to provide an alternating voltage as mains voltage and a direct voltage from a battery system as safety power source. Such a battery system is, for example, a central battery system or a group battery system. In the event of a mains voltage failure, i.e. AC power supply 3 failure, a switch-over device 5 switches over to the DC power supply 4. This switch-over device 5 is part of the central control unit 2. Another part of the central control unit 2 is at least one polarity-reversing device 8 which, in a first embodiment, is arranged between the switch-over device 5 and the DC power supply 4. It is likewise possible - see the dashed illustration of the polarity reversing device 8 - that the polarity-reversing device 8 be arranged between the switch over device 5 and the power supply line 6. In this design, there is also provided a current/voltage detection device 9 in the central control unit 2, between the polarity reversing device 8 and the power supply line 6. This current/voltage detection device serves to monitor the power supply provided by the central control unit 2 and detect load pulses possibly transmitted from the consumers 7 to the central control unit 2. This means that the current/voltage detection device 9 detects respective changes of current and/or voltage and induces, where necessary, respective reactions. The different consumers may include a different number of components. If the consumers 7 are lights, same comprise at least one luminous element 23, see also Fig. 3 to 5. With certain luminous elements 23 the consumers 7 furthermore comprise an electric or electronic ballast 18 and, where applicable, a load device 17, a polarity reversal detection device 12, a controlling/monitoring device 13, a conversion device 14, an overvoltage protection device 19, and addressing device (not shown) and, if applicable, a rectifier 20. Fig. 1 shows the different consumers 7 represented by two square subgroups. However, 7782284_1 12 both subgroups may be arranged in one housing, i.e. directly in the consumer. Also, it is possible that, for example, one of the subgroups, see reference number 15, is designed as a module. This module can be assigned to the respective consumer 7 and, in particular, connected to same from the outside, or as an integrated module from the inside. The module 15 allows, for example, an adaptation of consumers that are not provided with the possibility of detecting polarity reversals of the supply voltage according to the invention. Fig. 2 schematically shows the polarity-reversing device 8 according to Fig. 1. As was already described there, same may be assigned only to the DC power supply 3, or to same and the AC power supply 4. The polarity-reversing device 8 is configured in a full bridge arrangement 10 of a number of switching units 11. Depending on the position of the different switching units 11 a respective polarity reversal of the DC supply voltage is realized, see for example Fig. 6. In the position of the switching units 11 depicted the supply voltage passes without a polarity reversal, while by switching the switching units 11 arranged diagonal relative to each other into the respective other switch position a polarity reversal of the DC supply voltage takes place. It is noted at this point that the switching units 11 according to Fig. 2 are illustrated only schematically, whereby, as a rule, semiconductor switching units are used that do not include mechanical or electromechanical components. However, a realization of the polarity-reversing device 8, for example, with electromechanical switching units 11 is possible. Fig. 3 shows parts of the consumer of Fig. 1, and in particular the consumer 7 with the luminous element 23 and the electronic ballast 18. The electronic ballast 18 comprises various components which are known per se, e.g. fuse 28, radio interference filter 24, rectifier 25, filter capacitor 26 and control circuit 27. The control circuit 27 serves, for example, as a converter stage for providing the luminous element 23 with the additional possibility of switching on and off, and for dimming the luminous element 23. In Fig. 4 and Fig. 5 two embodiments of a consumer 7 with different controlling/monitoring devices 13 are illustrated. The other components, see luminous element 23 and ballast 18, are constructed similarly in both embodiments, see also Fig. 3. However, in the embodiments shown, the respective fuse 28 is no longer disposed in the ballast 18, but now in the controlling/monitoring device 13. 7782284_1 13 The controlling/monitoring device comprises an overvoltage protection device 19 with a voltage-dependent resistor (varistor) and the fuse 28, a rectifier 20 and a voltage detection device 30, respectively current detection device 29, as well as a microprocessor (not shown) with a coding switch for assigning a device address. According to Fig. 5 the controlling/monitoring device 13 monitors the voltage in order to detect respective polarity reversals in the voltage and generate a corresponding signal, while in the embodiment according to Fig. 4 a current monitoring is accomplished by the current detection device 30. However, in this embodiment, too, a detection of the corresponding polarity reversals and a generation of an associated signal is realized analogously. This signal is converted into a corresponding digital information signal in the form of a bit pattern, also see Fig. 6. The digital information signal corresponds to the information signal encoded in voltage or current in the central control unit 2. This information signal serves in the controlling and, if applicable, in the addressing of one, more or all consumers. If necessary, the controlling/monitoring device 13 may comprise a conversion device 14, also see Fig. 1, to generate such a digital control signal, respectively bit pattern. Same receives from the polarity reversal detection device 12 of the respective voltage detection device 30, respectively current detection device 29 a polarity reversal or polarity-reversing signal and generates from same the digital information signal, respectively corresponding bit pattern. As the information signal is to realize in particular a controlling of the consumer, a connection line is provided in the illustrated embodiments between the microprocessor of the polarity reversal detection device 12 / conversion device 14 and the control circuit 27 of the ballast 18, see also control connection 21 to the controlling/monitoring device 13. By means of this connection line it is possible to switch the respective luminous element 23 on/off and dim it by the associated control circuit 27 as part of a load controlling device 22. It is noted at this point that with an AC supply voltage a variation of current/voltage may be realized by a separate current/voltage varying device 16, as is described for example in EP 1 170 849 B1. Same could be used, for example, only for the AC power supply, while it is replaced in the DC power supply by the corresponding polarity-reversing device 8 for encoding an information signal. It is also possible, however, that the polarity-reversing 7782284_1 14 device 8, see for example the alternative arrangement according to Fig. 1, is also used for the AC supply voltage, i.e. the alternating mains voltage is influenced by the polarity reversing device to such an extent that a sequence of phases with a voltage interruption and phases without a voltage interruption is generated in response to the control information to be transmitted, whereby the information signal may contain only a control information or, if applicable, a control information and an address information. Moreover, it is possible to use the polarity-reversing device in such a manner that it is substantially utilized as a controlled rectifier so that, with an AC supply voltage, a bit pattern dependent sequence of phases with rectification and phases without rectification of the supply voltage is transmitted. With such an encoding of the type mentioned last no interruption of the supply voltage would occur. Moreover, it has to be noted that also feedbacks from the consumer to the central control unit 2 are feasible. See, for example, the load device 17 which may be a part of the ballast 18 or also of the controlling/monitoring device 13. The load device 17 is switched to be active for a short period by the consumer and causes, for example, a reduction of the load current or the respective voltage. By operating the load device 17 a corresponding load pulse is obtained, or a sequence of load pulses upon the multiple use of the load device. A sequence of the load pulses may also constitute an encoding of an information signal which, in this case, is transmitted from the consumer 7 to the central control unit 2, however. The current/voltage detection device 9, see Fig. 1, serves in the detection of the load pulses. Thus, each consumer is capable of transmitting, for example, status information, acknowledgment signals or the like to the central control unit 2. Fig. 6 shows a number of polarity reversals of a DC supply voltage. This means, in the corresponding sections 31, 33, 35 and 37 the DC supply voltage is transmitted unchanged, while the polarity thereof was reversed in sections 32, 34 and 36, see Fig. 1 and 2. The different sections 31 and 37 are transmitted through the supply line 6 to at least one consumer 7, where they are detected by the voltage detection device 29 as polarity reversal detection device 12, see Fig. 5. The different polarity reversals result in a polarity-reversing signal which is converted by the conversion device 14 into a digital information signal or bit pattern. Fig. 6 shows two different embodiments for a generated information signal, respectively bit pattern. It is conceivable, for example, that each polarity-reversing operation, see the polarity reversal between sections 31 and 32, generates a bit, see in Fig. 6 the upper 7782284_1 15 diagram in the right half. Upon each further polarity reversal, again, a respective bit is generated in each case, see for example the polarity reversal from section 32 to 33, from 33 to 34 etc.. Also, it is conceivable that one bit corresponds to a polarity-reversed section of the supply voltage, see in Fig. 6 the lower diagram on the right side. This means that one bit is generated, for example, by the polarity-reversed section 32 over the entire length thereof. This applies analogously to the other polarity-reversed sections 34 and 36. The corresponding coding of the information signal may be coded by the time succession of the corresponding bits, the time length of different bits and corresponding combinations and further evaluations of the bit pattern. It is further conceivable that, for example, a first polarity reversal generates a "positive" bit and a directly succeeding polarity reversal generates a "negative" bit, so that bit sequences are possible that are derived from the leading edge steepness or trailing edge steepness (+/- d/dT). According to the invention, in particular with a DC power supply, i.e. battery operation of an emergency/safety lighting system, a simple and reliable transmission of an information in a digital way as a bit pattern is realized by performing simply polarity reversal operations. The respective consumers comprise suited devices for monitoring, detecting and decoding the sequence of polarity reversals based on the polarity reversal of the power supply. In this design, it is furthermore possible to use the polarity-reversing device and the respective detection of the polarity reversals also for the AC supply voltage, i.e. mains voltage. In the arrangement described, in particular the circuit part 13 proves to be significant for the feasibility of the method as critical recharging losses particularly by capacitors in the electronic ballast 18, 22 are avoided by the additional upstream rectification 20 because the polarity reversal operations in this circuit part are not effective as such as the polarity there is not changed, but merely a time-limited interruption occurs. Without the circuit part 13 the input capacitances of the electronic ballast have to be completely recharged upon each polarity reversal operation, which results in increased recharging losses and leads to an impermissible temperature rise in the units, especially the polarity-reversing device 8 of the central control unit 2, and causes increased EMC critical interference voltages on the power supply line 6. 7782284_1

Claims

1. An emergency/safety lighting system comprising at least one central control unit, an AC and DC power supply, a switch-over device switchable between these two power supplies, and a number of consumers connected to the central control unit by a power supply line, wherein the central control unit comprises a polarity-reversing device assigned at least to the DC power supply, which can be controlled for the in particular binary encoding of an information signal by means of a sequence of polarity reversals of the supply voltage provided by the power supply, which encoded information signal can be transmitted by the supply voltage from the central control unit through the power supply line to at least one consumer.

2. The emergency/safety lighting system according to claim 1, wherein the polarity reversing device is arranged between the DC power supply and the switch-over device.

3. The emergency/safety lighting system according to claim 1 or 2, wherein the polarity-reversing device is arranged between the switch-over device and the power supply line.

4. The emergency/safety lighting system according to one of the preceding claims, wherein the central control unit comprises a current/voltage detection device.

5. The emergency/safety lighting system according to one of the preceding claims, wherein one polarity-reversing device is assigned at least to each final circuit.

6. The emergency/safety lighting system according to one of the preceding claims, wherein the polarity-reversing device comprises a full bridge arrangement of switching units.

7. The emergency/safety lighting system according to one of the preceding claims, wherein the consumer comprises a polarity reversal detection device for detecting polarity reversals of the supply voltage.

8. The emergency/safety lighting system according to one of the preceding claims, wherein current and/or voltage of the supply voltage can be monitored by the polarity reversal detection device (12).

9. The emergency/safety lighting system according to one of the preceding claims, 7782284_1 17 wherein a controlling/monitoring device is assigned to the consumer which comprises at least the polarity reversal detection device.

10. The emergency/safety lighting system according to one of the preceding claims, wherein the controlling/monitoring device comprises a conversion device converting a sequence of polarity reversals of the supply voltage into a binary consumer information signal.

11. The emergency/safety lighting system according to one of the preceding claims, wherein the consumer information signal includes, in addition to a control information for the actual controlling of the consumer, an address information for selectively addressing each consumer, or for the group-wise addressing of a plurality of consumers.

12. The emergency/safety lighting system according to one of the preceding claims, wherein the controlling/monitoring device is configured as a separate module connectable to the consumer or insertable into same.

13. The emergency/safety lighting system according to one of the preceding claims, wherein in the case of an AC supply voltage a current/voltage varying device is provided for the binary encoding of an information signal contained in the supply voltage and transmittable through the power supply line.

14. The emergency/safety lighting system according to one of the preceding claims, wherein the polarity-reversing device is usable as a current/voltage varying device.

15. The emergency/safety lighting system according to one of the preceding claims, wherein the polarity-reversing device is usable as a rectifier in the case of an AC supply voltage.

16. The emergency/safety lighting system according to one of the preceding claims, wherein the consumer comprises a load device for influencing a load current.

17. The emergency/safety lighting system according to one of the preceding claims, wherein the influencing of the load current is formed of a number of load pulses encoding a return information signal.

18. The emergency/safety lighting system according to one of the preceding claims, wherein the consumer comprises an electric or electronic ballast. 7782284_1 18

19. The emergency/safety lighting system according to one of the preceding claims, wherein the controlling/monitoring device comprises an overvoltage protection device and/or a rectifier.

20. The emergency/safety lighting system according to one of the preceding claims, wherein the controlling/monitoring device comprises a control connection for controlling and/or monitoring a load controlling device, such as ballasts or the like.

21. A method for controlling and/or monitoring an emergency/safety lighting system comprising at least one central control unit and consumers connected to same by a power supply line, wherein an in particular binary-coded information signal is transmitted as part of a supply voltage from the central control unit through the power supply line to at least one consumer, which central control unit is selectively connected to an AC and DC power supply, wherein an encoding of the information signal is realized by a sequence of polarity reversals of the supply voltage by means of a polarity-reversing device of the central control unit.

22. The method according to claim 21, wherein the DC supply voltage polarity is reversed.

23. The method according to claim 21 or 22, wherein the consumer detects the sequence of polarity reversals by means of a polarity reversal detection device and evaluates it as a binary information signal.

24. The method according to one of the preceding claims 21 to 23, wherein the binary information signal contains control information and additionally address information.

25. The method according to one of the preceding claims 21 to 24, wherein with an AC supply voltage a sequence of variations of the supply voltage is realized to encode a binary information signal.

26. The method according to claim 25, wherein the polarity-reversing device varies the AC supply voltage by transmitting voltage phases with and without rectification.

27. The method according to one of the preceding claims 21 to 26, wherein the consumer generates at least one load pulse which is transmitted as consumer information signal through the power supply line to the central control unit and is detected and evaluated by same. 7782284_1 19

28. The method according to claim 27, wherein load pulses are transmitted in a time sequential sequence for the binary encoding of the consumer information signal.

29. The method according to one of the preceding claims 21 to 28, wherein the polarity reversal detection device monitors current and/or voltage and an overvoltage protection and/or a rectification are performed by means of an overvoltage protection device and/or rectifier as part of a controlling/monitoring device assigned to the consumer. CEAG Notlichtsysteme GmbH Patent Attorneys for the Applicant SPRUSON & FERGUSON 7782284_1