IMPROVEMENTS IN OR RELATING TO LIGHTING SYSTEMS

Abstract: A lighting system comprises a multiplicity of luminaires (A1 to A4, B1 to B4, C1 to C4 and D1 to D4) and a central control unit (1) for controlling the light outputs of the luminaires. The luminaires are divided into a plurality of groups, each arranged to receive its own control signal from the central control unit and having a respective local control means (7, 8) which is arranged to control the light outputs of individual luminaires of the group in dependence upon both a signal from the central control unit (1) and information stored in the local control means (7, 8).

Description: Improvements in or relating to lighting systems This invention relates to a lighting system and to a method of controlling such a system. Traditionally, in a controlled lighting system there have been a multiplicity of luminaires at desired remote locations, each connected via its own wiring to a dinner provided in a control roon. Each dimmer has been controlled by a respective channel of a control unit so as to provide the desired degree of lighting from each luminaire. More recently it has been proposed to site the dimmers adjacent to their respective luminaires, again with each dimmer being controlled by a respective channel of a central control unit. In the cases referred to above, each individual luminaire is directly controlled by a respective control channel of the central control unit and the number of luminaires that can be controlled is limited by the number of control channels that are available. It is an object of the invention to provide a lighting system and a method of controlling a lighting system that overcomes or mitigates the disadvantages referred to above. According to the invention there is provided a controlled lighting system comprising a multiplicity of luminaires and a central control unit for controlling the light outputs of the luminaires, the luminaires being divided into a plurality of groups, each of the groups being arranged to receive its own control signal from the central control unit and having a respective local control means which is arranged to control the light outputs of individual luminaires of the group in depen¬ dence upon both a signal from the central control unit and information stored in the local control means. Preferably each group of luminaires comprises a plurality of luminaires, but in special circumstances there may be one or more groups of luminaires which consist of only a single luminaire and there may also be other individual luminaires that are controlled directly from the central control unit and not provided with a local control means. The local control means of the luminaires may be connected to the central control unit via a common control loop and each local control means may be arranged to receive control signals from the central control unit via a respective control channel of the common control loop. Usually the common control loop will be a wire loop but, if desired, a remote control system using for example a radio or infra-red control may be used. Thus, it will be seen that in accordance with the invention it is possible to control several luminaires through the same control channel of a central control unit and yet provide individual control of the light outputs of the luminaires. Thus relatively few control channels can be used to control a large number of luminaires. At least one, and advantageously each, of the local control means may be pre-programmed when the lighting system is set up so as to control each of the individual luminaires to provide a respective desired light output in response to a given control signal from the central control unit. Preferably the pre-programming is such that the light outputs of individual luminaires of the associated group are varied proportionally in dependence upon the signal from the central control unit, the ratios of the light outputs having been selected by the pre-programming. An arrangement of this kind is descri¬ bed below with reference to the drawings. Another possibility, however, is to create a store at the local control means of respective values of light outputs for each of the luminaires for different control signals from the central control unit; in that case the ratios of the light outputs of the individual luminaires in a group will vary. Each luminaire preferably has an associated dimmer for controlling its light output, the dimmer being arranged to be controlled by the local control means. Advantageously a dimmer module is provided as a plug-in unit for the luminaire the plugging-in of the module serving to provide both a mechanical and an electrical connection between the dimmer module and the luminaire. Each local control means may comprise a single control unit having separate outputs for each of the luminaires it is controlling but, preferably, as in the illustrated embodiment of the invention described below, each local control means comprises a plurality of local control units, each associated with a respective one of the luminaires of the group controlled by the local control means. Preferably the local control means are positioned at locations remote from the central control unit and preferably adjacent to or on the luminaires that they are arranged to control. While the present invention is especially advantageous where one or more groups of luminaires, each group comprising a plurality of luminaires, are provided (with or without other luminaires that are individually controlled by dedicated channels of the central control unit) it is also possible for the invention to be of benefit where each luminaire is individually controlled by a respective control channel from the central control unit. Such an arrangement enables a reduced brightness to be provided by the luminaire, even when the signal from the central control unit indicates full brightness. Accordingly, the present invention also provides a controlled lighting system comprising a multiplicity of luminaires and a central control unit for varying the light outputs of the luminaires during use by means of a multi-channel control signal, the luminaires being arranged to respond to respective channels of the control signal and having respective local control units which are arranged to be preset by a user to control the actual light output in accordance with a combination of the control signal from the central control unit and the presetting of the local control unit. The present invention also provides a method of controlling a lighting system comprising a multiplicity of luminaires divided into a plurality of groups, in which method the light outputs of individual luminaires of a group are controlled in dependence upon both a signal from a central control unit that is common to all the luminaires of the group and upon information stored in a control means local to the group and providing respective controls for each of the luminaires of the group. The use of a plug-in dimmer module as described above can be of advantage in other forms of lighting system since it provides a user of the system with an option to provide a dimming facility on any of a large number of luminaires without having to acguire a dinner for each luminaire; rather a user is able to plug in dimmer modules to those particular luminaires on which the dimming facility is required. Accordingly the present invention provides a luminaire assembly comprising a luminaire including a light source, and a dimmer module, the luminaire being operable without the dimmer module but also being able to receive the dimmer module as a plug-in fit in which the di mer module is mechanically and electrically connected to the luminaire and dimming means is interposed in the electrical power supply to the light source. The luminaire assembly may be part of a lighting system having some or all of the features of the lighting system referred to above or below. By way of example, an embodiment of the invention will now be described with reference to the accompanying drawing, of which: Fig. l is a diagram of an entertainment lighting system comprising a plurality of luminaires; Fig. 2 is a block diagram of a control arrangement for one of the luminaires; and Fig. 3 is a front view of a dimmer module for each luminaire. The entertainment lighting system shown in Fig. 1 has a central control unit 1, a main power supply 2 and four groups A, B, C and D of luminaires. Each of the groups of luminaires comprises four luminaires referenced Al to A4, Bl to B4, Cl to C4 and Dl to D4. Associated with each luminaire is a local control unit and a dimmer for controlling the light outputs of the luminaires. The local control units and the dimmers are mounted on the luminaires and are not shown separately in Fig. 1. Each luminaire is connected by a power cable 3 to the main power supply 2 and by a control cable loop 4 to the central control unit 1. The central control unit l shown in the drawing has nine channels of which only the first four are used in the illustrated embodiment. The central control unit 1 provides a multiplexed control signal with luminaires of group A controlled by the first channel, luminaires of group B controlled by the second channel, luminaires of group C controlled by the third channel and luminaires of group D controlled by the fourth channel. The luminaires of each group may be positioned in proximity to one another but they may also be spaced apart with other luminaires of other groups interposed between them. As can be seen in Fig. 1, all the luminaires of a group are directed towards the same subject referenced SI to S4 in Fig. 1; whilst that is an advantageous arrangement which has the advantage that there is a clear connection between the desired relative brightness levels of the luminaires within one group, it is not an essential feature of the invention. The central control unit 1 is a conventional control unit for a lighting control system of a kind already available from many manufacturers. The unit is in accordance with the industry standard DMX512 (1991) protocol. Examples of suitable units are the Regal II+4 DMX Control System available from CCT Lighting Ltd. , Sutton, England, the Gemini 2+, Galaxy Nova and MX control systems available from Strand Lighting, Isleworth, England, and the Obsession, Expression, Impression, Concept, Insight, Microvision, Idea and Acclaim systems available from Electronic Theatre Control Inc., Niddleton, USA. Fig. 2 shows the control arrangement at each luminaire. The control cable loop 4 is connected to a master control microprocessor 5 which is connected to receive an input from a channel selector switch 6 comprising three decimal switches 6A, 6B and 6C. An output from the master processor 5 is passed to a slave processor 7 having an associated local light output level setting switch 8. The output of the slave processor 7 is connected to a dimmer circuit 9 interposed between a mains power supply 10 and an output 11 to a lamp. The slave processor 7 controls the dimmer circuit 9 in dependence upon the combination of the setting of the switch 8, which is a hexadecimal switch giving 16 proportionate output levels including 0% and 100%, and the output level signal from the master processor 5. When setting up the system an operator sets the three decimal switches 6A, 6B and 6C of a luminaire to the channel of the control unit 1 that has been selected to control the group of luminaires to which the particular luminaire belongs. The channel selector switch 6 then causes the master processor 5 to react to control signals from the control unit 1 in the selected channel but not to signals of any of the other channels in the multiplexed control signal. The operator also selects the ratio of the light outputs of the luminaires of a group and adjusts the switches 8 of the local control units of the luminaires accordingly. Thus, for a particular example, in the case of the luminaires of group A, the proportional controls provided by the switches 8 are set so that the luminaire Al provides full output, luminaire A2 60% output, luminaire A3 40% output and luminaire A4 80% output. The other luminaires are set to provide the following outputs: Bl - 100% Cl - 100% Dl - 100% B2 - 48% C2 - 36% D2 - 60% B3 - 32% C3 - 24% D3 - 40% B4 - 64% C4 - 48% D4 - 80% In operation the settings indicated above determine the relative amounts of light outputs of luminaires in a group while the signal from the central control unit l determines the general level of output. Thus, for example, with channel 1 set to "10" as shown, luminaire Al will be at full light output, luminaire A2 at 60% output, luminaire A3 at 40% output and luminaire A4 at 80% output. Similarly with channel 2 set to 8, luminaire Bl will be at 80% of full light output, luminaire B2 at 38.4% output, luminaire B3 at 25.6% output and luminaire B4 at 51.2% output. Thus the light output of each luminaire is dependent upon the control signal from the central control unit and the proportional control preselected by the operator when the lighting system is first set up. It will be seen that in the example of the invention just described, only four control channels are used to control sixteen luminaires which would have required 16 control channels using a conventional control system. As already described, the dimmer circuit 9 is interposed between the mains power supply 10 and the output 11 to a lamp. Thus the physical position of the dimmer circuit 9 (and the processors 5, 7 and switches 6, 8) is flexible. In an especially preferred arrange¬ ment shown in Fig. 3 the dimmer circuit 9 and the other components shown in Fig. 2 (processors 5, 7 and switches 6, 8) are incorporated in a dimmer module that is a plug- in fit into a luminaire housing. With the dimmer module unplugged the mains power supply 10 is directly connected to the output 11 and no dimming facility is provided. When the dimmer module is plugged in the direct electrical connection between the mains power supply 10 and the output 11 is broken and replaced by the connec¬ tion shown in Fig. 2; at the same time as the dimmer module is electrically connected it is also mechanically connected to the luminaire. Fig. 3 shows a dimmer module for plug-in connection as just described. The module has a front panel on which are a mains power socket 15 (for connection to the mains power supply 10 of Fig. 2), input and output control cable connections 16A and 16B, switches 6A, 6B and 6C for setting the channel to which the module responds (in the described embodiment there are 512 channels), switch 8 for setting the local proportionate light output control and a plug 17 for connection to a luminaire housing in the same way as a mains power lead can be directly connected to the luminaire housing. When the dimmer module of Fig. 3 is in use a mains power lead (10 in Fig. 2) is inserted into the socket 15 control cables (4 in Fig. 2) are connected to the connections 16A and 16B and the plug 17 is plugged into a socket in the luminaire housing 18 shown in dotted outline. The operator sets the switches 6A, 6B and 6C to the selected channel to determine the group to which the luminaire belongs and sets the switch 8 to a chosen proportionate setting to select the brightness of the luminaire compared to other luminaires of the same group, or, especially in a case where the luminaire is not part of a group, sets the reduction in brightness of the luminaire from the brightness signalled from the central control unit. If the dimmer facility is not required, the dimmer module is unplugged from the luminaire housing 18 and the mains power lead (10 in Fig. 2) unplugged from the dimmer module and plugged directly into the luminaire housing.

Claims: Claims 1. A lighting system comprising a multiplicity of luminaires and a central control unit for controlling the light outputs of the luminaires, the luminaires being divided into a plurality of groups, each of the groups being arranged to receive its own control signal from the central control unit and having a respective local control means which is arranged to control the light outputs of individual luminaires of the group in depen- dence upon both a signal from the central control unit and information stored in the local control means. 2. A lighting system as claimed in claim 1, in which each group of luminaires comprises a plurality of luminaires. 3. A lighting system as claimed in claim 1 or 2, in which the local control means of the groups of luminaires are connected to the central control unit via a common control loop. 4. A lighting system as claimed in claim 3, in which each local control means is arranged to receive control signals from the central control unit via a respective control channel of the common control loop. 5. A lighting system as claimed in any preceding claim, in which at least one of the local control means is arranged to be pre-programmed such that the light outputs of individual luminaires of the associated group are varied proportionally in dependence upon the signal from the central control unit, the ratios of the light outputs having been selected by the pre-programming. 6. A lighting system as claimed in any preceding claim, in which each luminaire has an associated dimmer for controlling its light output, the dimmer being arranged to be controlled by the local control means. 7. A lighting system as claimed in any preceding claim in which each local control means comprises a plurality of local control units, each associated with a respective one of the luminaires of the group controlled by the local control means. 8. A lighting system as claimed in any preceding claim, in which the local control means are positioned at locations remote from the central control unit. 9. A lighting system as claimed in any preceding claim, in which the local control means are positioned adjacent to or on the luminaires that they are arranged to control. 10. A controlled lighting system comprising a multi¬ plicity of luminaires and a central control unit for varying the light outputs of the luminaires during use, the luminaires being divided into a plurality of groups, the number of groups being substantially smaller than the number of luminaires, the luminaires of a given group all being arranged to receive the same light output control signal from the central control unit but having respec¬ tive local control units which are arranged to be preset by a user to control the actual light output in accor¬ dance with a combination of the control signal from the central control unit and the presetting of the local control unit. 11. A controlled lighting system comprising a multi¬ plicity of luminaires and a central control unit for varying the light outputs of the luminaires during use by means of a multi-channel control signal, the luminaires being arranged to respond to respective channels Of the control signal and having respective local control units which are arranged to be preset by a user to control the actual light output in accordance with a combination of the control signal from the central control unit and the presetting of the local control unit. 12. A method of controlling a lighting system comprising a multiplicity of luminaires divided into a plurality of groups, in which method the light outputs of individual luminaires of a group are controlled in dependence upon both a signal from a central control unit that is common to all the luminaires of the group and upon information stored in a control means local to the group and provid- ing respective controls for each of the luminaires of the group. 13. A method as claimed in claim 12, in which the lighting system is as claimed in any one of claims 2 to 11. 14. A luminaire assembly comprising a luminaire includ¬ ing a light source, and a dimmer module, the luminaire being operable without the dimmer module but also being able to receive the dimmer module as a plug-in fit in which the dimmer module is mechanically and electrically connected to the luminaire and dimming means is inter¬ posed in the electrical power supply to the light source.

Inventors: HINDLE DONALD DUNCAN, SHAW JOHN ANTHONY, HINDLE, DONALD, DUNCAN, SHAW, JOHN, ANTHONY
Applicants: CCT LIGHTING LTD, HINDLE DONALD DUNCAN, SHAW JOHN ANTHONY, CCT LIGHTING LIMITED, HINDLE, DONALD, DUNCAN, SHAW, JOHN, ANTHONY
Application year: 1996
Main classification: H05B37
IPC codes: F21S8, H05B37