WO2004073357A2

WO2004073357A2 - Lighting system with global bus and local intelligence

Info

Publication number: WO2004073357A2
Application number: PCT/IB2004/000381
Authority: WO
Inventors: Ronald Ivo Maria Verbeeck
Original assignee: Etap N.V.
Priority date: 2003-02-17
Filing date: 2004-02-16
Publication date: 2004-08-26
Also published as: EP1595430A2; NL1022715C2; WO2004073357A3

Abstract

A lighting system is controlled by means of a control bus, to which one or more first lighting units are coupled. A control unit coupled to the control bus sends a command which indicates a power setting by means of which the one or more first lighting units set a power used for lighting in accordance with the command. A second lighting unit is provided with a light meter for obtaining a light level measurement of at least light which lights a location lighted by the second lighting unit. The second lighting unit is also coupled to the bus, but it is arranged to use the controlled power level as ideal value for controlling the power for lighting depending on the light level measurement.

Description

P62210PC00

Title: Lighting system with global bus and local intelligence

The invention relates to a lighting system and to lighting units for use in such a system.

It is known to use light controllers to control the power supplied to lamps. The power can be set by means of a simple setting knob, but use may also be made of a control loop with, for instance, a light-sensitive element by means of which the power is controlled such that a requested light level is realized.

Increasingly, digital techniques are used to realize such controllers. Use is made of inter alia bus connections to which a number of lighting units and one or more control units are connected together. In this case, a control unit determines the desired power level and sends one or more corresponding messages via the bus connection to the lighting units, with commands to switch lamps on or off or to set the power supplied at a certain level. The control unit can generate the commands for various reasons, for instance depending on the time of day, in response to operation of a light button or on the basis of an amount of outside light measured. Sometimes, the commands also depend on information from messages received by the control unit via the bus from lighting units or other units, but it is not essential whether the bus connection also admits such a reverse communication.

In such a bus system, the intelligence is mainly concentrated in the control unit. In this unit, the information is collected which is needed for the control of the lighting units. Thus, the lighting units themselves can be kept rather "dumb" by limiting their operation to setting the commanded power levels. The costs for the lighting units thus remain low. A disadvantage of such a system is that a complex programming of the control unit is necessary if one wants to take diversity in the lighting situation in different places in a building into account. In that case, no use can be made of "broadcast" commands from the control unit which have the same content for all lighting units, but the commands need to be adjusted depending on the situation of the respective lighting unit. This can considerably increase the costs of the installation (including configuration and operationalization) of such a system. However, the alternative of having all lighting systems react intelligently, depending on the local lighting situation, undoes many advantages of a bus system.

It is therefore one of the objects of the invention to provide a lighting system with a bus connection in which, by means of a control unit, commands for situation-independent lighting units can be sent, which same commands, however, can also be used locally for intelligent, situation-dependent control.

The invention provides a lighting system according to claim 1. According to the invention, one and the same type of command sent via the bus connection is processed differently by different lighting units. By "dumb" lighting units, a number from such a command is used as a power setting, while another, "smart" lighting unit uses the same number for determining an intensity reference in a power control, partly depending on the light level of light coming from outside the smart lighting unit. This allows a command addressed to a group of lighting units to be treated differently by "smart" units than by "dumb" units in the group. Thus, one single command is sufficient for such a heterogeneous group. Also, corresponding commands, which only differ in that a smart and dumb unit, respectively, is addressed, can be used to control dumb and smart units. Thus, generating commands is simpler than when the content of the commands needs to be determined depending on the type of unit. Here, it is preferably assumed that, when the number in the command has a maximum power value, an intensity reference needs to have the maximum value independently attainable by the second lighting unit and that, according as the number in the command indicates a smaller power value, the intensity reference is proportionally smaller than the independently attainable maximum value.

The smart lighting unit preferably comprises a memory for the independently attainable maximum value. This can then be set in the factory for a standard environment or, in some cases, depending on a local lighting situation. Preferably, a non-volatile memory such as an EPROM is used for this.

For the control, use can be made of, for instance, a control which reduces the contribution of the smart lighting unit to the light level according as the lighting contribution from outside the smart lighting unit is greater, but such that the total light level still increases according as the lighting contribution from outside the smart lighting unit increases. Thus, a natural reaction to changes in environmental light is partly compensated, which has a more natural effect.

Preferably, the second lighting unit contains an internal lighting unit of the "dumb" type, to which, in response to the command on the bus, an adjusted command is supplied to control the power setting. Thus, a standard dumb internal lighting unit can be used. In the case that the internal lighting unit is fed via the bus, at least a part of the rest of the smart lighting unit is preferably fed via the lighting mains. Thus, the smart lighting unit is compatible with dumb lighting units with respect to bus load.

Preferably, the internal lighting unit contains a backup supply for generating light in an emergency lighting situation. In this case, preferably, a switch unit is used to supply, when the lighting unit has been switched to the emergency lighting situation, commands to the internal supply unit, bypassing the controller that carries out the adjustment. Thus, the system also remains operational in the emergency lighting situation.

These and other objectives and advantages of the lighting system, the lighting unit and the method of installation and use of such a system will be further described with reference to the following figures.

Fig. 1 shows a lighting system Fig. 2 shows a control characteristic Fig. 3 shows a graph of the contribution of a lighting unit to the light level

Fig. 4 shows an embodiment of a lighting unit

Fig. 1 shows a lighting system provided with a control unit 12, a bus 10, a number of "dumb" lighting units 14a-c, a smart lighting unit 16 and a lighting mains connection 18. Control unit 12 is coupled to lighting units 14a-c, 16 via bus 10. Lighting units 14a-c, 16 are further coupled to lighting mains connection 18. Lighting mains connection 18 is shown by a single line, but it will be clear that this generally represents a couple of lighting mains conductors, between which a lighting mains voltage is present. Likewise, bus 10 will generally contain multiple conductors; however, without deviating from the invention, use can be made of wireless bus communication, for instance with RF electromagnetic signals.

One of the dumb lighting units 14a is shown in more detail. It contains a controller 140, a power supply circuit 142 and a lamp 144. Controller 140 is coupled between bus 10 and a control input of power supply circuit 142. Power supply circuit 142 is coupled between lighting mains 18 and lamp 144. Controller 140 and power supply circuit 142 are preferably integrated in one standard construction component, to enable simple production. The other dumb lighting units 14b-c have a similar structure.

Smart lighting unit 16 contains a controller 160, an internal dumb lighting unit 162 of the same type as the other dumb lighting units 14a -c, a light meter 164 and a memory 166. Light meter 164 measures light levels (for instance light intensity, luminous intensity). Controller 160 is coupled to internal dumb lighting unit 162, to light meter 164, memory 166 and to bus 10. Further, controller 160 is coupled to lighting mains connection 18. Controllers 160 and 162 are preferably integrated in one construction component, in which light meter 164 can also be mechanically integrated, or can be connected via wiring.

In operation, control unit 12 sends messages with commands to lighting units 14a-c, 16. Controllers 140, 160 in the lighting units 14a-c, 16 receive the commands and control the power consumption of a lamp (or lamps) 142, 162 in the lighting unit 14a -c, 16, depending on the commands. Here, a same type of message is used for both dumb lighting units 14a-c and smart lighting unit 16.

In one embodiment, a message contains, for instance, a field by means of which address information for an individual lighting unit 14a -c, 16 is addressed. Also, for instance, a type of command can be used with address information which makes it possible to address, alternatively, an individual lighting unit 14a-c, 16, a group of the lighting units 14a-c, 16 simultaneously, or all lighting units 14a -c, 16 simultaneously, for which the command is intended. The message further contains information representing an instruction code and, optionally, control data. Various forms of commands are possible: the invention is not limited to use with a specific type of command format.

The commands may inter alia be dim commands, with an instruction code identifying the command as dim command, while the control data represents a number representing a desired power supply. When sending such a message over bus 10, controllers 140 of the dumb lighting units 14a-c check the value of the address information and, if necessary, compare it to an individual address or a group address of the dumb lighting unit 14a -c. If this address information indicates that the command is intended for the respective lighting unit 14a-c, for a group to which this lighting unit 14a-c belongs or for all lighting units 14a -c, 16, then controller 140 will process the command. In that case, controller 140 reads the instruction code and controls power supply circuit 142 in accordance with the instruction code. If the instruction code is, for instance, an on/off command, then power supply from lighting mains connection 18 to lamp 144 will, for instance, be switched on or off. If the instruction code is a dim command, then controller 140 will read the control data from the command and controls power supply circuit 142 such that it supplies an amount of power determined by the control data from lighting mains connection 18 to lamp 144.

For controlling smart lighting unit 16, control unit 12 uses a same type of message as for controlling dumb lighting units 14a-c. Also, broadcast messages can simultaneously control smart and dumb lighting units 14a -c, 16 and/or a group comprising both dumb and smart lighting units 14a-c, 16. In response to reception of an external dim command from bus 10, in smart lighting unit 16, controller 160 generates an internal dim command for internal dumb lighting unit 162, which command contains calculated internal data for controlling the power supply. Controller 160 reads out a light level measurement from light meter 164 and calculates the internal data for the internal dim command depending on the light level measurement, on external data from the external dim command and, optionally, depending on information from memory 166. Controller 160 passes on other commands, such as external on/off commands, without a change from bus 10 to internal lighting unit, possibly adding additional commands, for instance an additional dim command with an "on" command. Internal dumb lighting unit 162 receives the internal commands and carries them out just like dumb lighting units 14a-c.

Fig. 2 shows a control characteristic, with a curve 30 therein for the amount of power P which controller 160 places in the internal command - which is plotted as a function of the controlled power X read by controller 160 from the external command - such as controller 160 calculates it in the case of a given light level measurement, or an average of such measurements over a certain period of time (both powers P, X plotted on a scale of the light levels realized by these powers). For reference, in the Figure, also, the one-to-one relation 36 is shown which exists, for dumb lighting units 14a-c, between the external command and the power P. As is clearly shown, the curve 30 gradually rises. Initially, the rise is relatively weak up to a data value 34 of X and then stronger, until, gradually, a rise proportional to the increase of X is reached. Data value 34 is determined by the light level measurement of light meter 164. The higher the light level measurement is, the higher the data value 34 becomes. So, curve 30 is a gradual version of an angled characteristic with a P which is initially zero up to data value 34 and then rises according to a straight line 32 proportionally to the increase of X. In one embodiment, controller 160 replaces the dim command by an

"off command in the case that the data X is more than a predetermined factor below data value 34 and supplies this "off command to internal lighting unit 162.

With an action according to a curve like curve 30, controller 160 ensures that the. external command from bus 10, which is a power control command for dumb lighting units, is used by the smart lighting unit for a control of the light level in such a manner that less power P is supplied as the location lighted by internal lighting unit 162 receives a higher light level from outside internal lighting unit 162. Fig. 3 shows a graph with a curve 40 of the contribution of lighting unit 162 to the light level at the location lighted by internal lighting unit 162, as a function of the external light level contribution from outside internal lighting unit 162 which is thus realized (expressed in power P supplied to the lamp, but drawn on the scale of light level). In the absence of an external contribution, lighting unit 162 makes a contribution determined by the dim command received. Above a threshold value 42, determined by the dim command received, the light level contribution of internal lighting unit 162 strongly decreases. Curve 40 is a gradual version of a drop 44 to threshold value 42 and no light level contribution above the threshold value 42.

Preferably, controller 160 treats a command with control data (value "X") which makes dumb lighting units produce a fraction F of their maximum attainable amount of light intensity Y0 as follows. Controller 160 treats the command as a command to realize, at the location lighted by internal lighting unit 162, the fraction F of the maximum light level attainable for lighting of that location by internal lighting unit 162 alone.

This can be realized in various manners. Preferably, light meter 164 is directed to the location lighted by internal lighting unit 162. In this case, controller 160 compares, for instance, the light level measurement from light meter 164 with the respective fraction of the maximum light level. The latter is read out by controller 160 from memory 166. In principle, the maximum light level depends on the conditions at the respective location, for instance the level of (mainly diffuse) reflection in the environment (dark or light carpet, for instance). Usually, the conditions are average and a standard maximum light level can be used which has been set independently of the location.

In one embodiment, it is possible to set the maximum light level in memory 166 depending on the environment, for instance upon installation. For this purpose, preferably, use is made of a non-volatile memory 166, such as an EPROM or a flash memory, so that the maximum light level remains permanently available. This value can also be determined in situ in that controller 160 measures the difference between light level measurements Yl, Y2 at different power supplies Pi, P2 (for instance maximum and minimum power supply), from which it calculates the maximum Ymax from which the external contribution Yext has been eliminated:

Yext = (P1*Y2-P2*Y1)/(P1-P2), wherein the powers PI are expressed on the scale of the light level reached by the power. Also, Yext can be determined from the minimum light level measurement in a daily cycle. In another embodiment, light meter 164 is directed externally, such that only or mainly the level of the external light level contribution Yext is measured which is incident on the lighted location and hardly, if at all, the light level contribution produced by internal lighting unit 162. In this case, controller 160 determines the control curve to be used by setting data value 34 proportionally to the Yext measured.

Controllers 140, 160 are, for instance, realized as suitably programmed integrated circuit microcontrollers, but use can also be made of circuits specially designed as controllers.

As described, controller 160 generates an internal dim command in response to an external dim command arriving over bus 10, with the power setting in the internal command being calculated from the power setting from the external command, depending on an internal light level measurement. In addition, it is preferably also possible for controller 160 to generate additional internal dim commands itself without the immediate trigger from an external dim command, for instance as a response to changes in the light level measurements (or change in a time average of the light level measurements over a certain period), or in response to an "on" command, where, in addition to a command for internal lighting unit 162, a dim command is generated as if the "on" command were a dim command for 100% power supply. Further, in the lighting unit, one ore more further sensors may be provided, such as a motion detector and/or other presence or absence detector and/or a remote control and/or a push button. These sensors operate instead of light meter 164 or in combination with light meter 164 to adjust the internal commands depending on sensor signals. By means of a motion detector, it is, for instance, possible to gradually dim, with respect to the light level externally indicated as desired, the desired light level to a certain level when nobody is present anymore. This may, for instance, be applied in large office accommodations with varying occupancy. By a gradual or partial adjustment of the desired light level, energy can be saved in the absence of a motion detection signal, but without (disturbing) switching and/or while maintaining a residual light level for the comfort of the people still present (so people are not sitting in an island of light in an otherwise dark room). Preferably, as described, internally in smart lighting unit 16, use is made of messages with internal commands of the same type as messages with external commands on bus 10, because, thus, use can be made of an existing dumb lighting unit 162 in smart lighting unit 16. However, instead, such internal messages may also be dispensed with, by having controller 160 directly control a power supply circuit.

Further, for feeding the controller 140 in dumb lighting units 14a -c, preferably, use is made of energy supply via bus 10. However, smart lighting unit 16 contains more than only a single controller (that is, in addition to the controller of internal lighting unit 162, also controller 160 and light meter 164). In order to prevent that, thus, more supply is taken up than by dumb lighting units 14a-c, at least controller 160 and light meter 164 are preferably fed from lighting mains connection 18.

In one embodiment, dumb lighting units 14a-c, 162 are provided with an internal backup supply which switches on the lighting unit 14a -c, 162 for feeding emergency lighting in an emergency lighting situation if the power supply via lighting mains 18 is cut off. In this embodiment, smart lighting unit 16 preferably contains switches to supply, in an emergency situation, messages from bus 10 directly to internal lighting unit 162, so bypassing controller 160. Fig. 4 shows a smart lighting unit 16 with a switch unit 50 with such switches. Switch unit 50 is placed between controller 160 and the bus input of internal lighting unit 162 and is controlled by controller 160, such that, when the voltage on lighting mains connection 18 fails, the bus input of internal lighting unit 162 is connected to bus 10, while, in the presence of voltage on lighting mains connection 18, controller 160 is connected to bus 10 at the bus input of internal lighting unit 162. Thus, smart lighting unit 16 remains accessible as a dumb lighting unit in the emergency lighting situation.

Fig. 4 further shows a backup supply 52, which is coupled to the internal controller (not shown, but analogous to controller 140) of internal lighting unit 162, for use in the emergency situation. Outside of the emergency lighting situation, the internal controller is preferably fed from bus 10.

Claims

1. Lighting system, provided with:

- a control bus;

- one or more first lighting units coupled to the control bus;

- a control unit coupled to the control bus, arranged for sending a command indicating a power setting by means of which the one or more first lighting units set a power used for lighting in accordance with the command;

- a second lighting unit provided with a light meter for obtaining a light level measurement of at least light lighting a location lighted by the second lighting unit, which second lighting unit is coupled to the bus and is arranged to determine, from the controlled power level, an intensity reference for controlling the power used for lighting depending on the light level measurement.

2. A lighting system according to claim 1, wherein the second lighting unit is provided with an internal lighting unit and a controller between the control bus and internal lighting unit and wherein the controller is arranged to calculate an adjusted power setting in response to the command and as part of the control, and to send a changed command to the internal lighting unit, in which the adjusted power setting has been included.

3. A lighting system according to claim 2, wherein the control bus is arranged for delivering supply to the internal lighting unit and wherein the second lighting unit is further provided with a lighting mains connection, from which the controller and/or the light meter are fed.

4. A lighting system according to claim 3, wherein the internal lighting unit is provided with an emergency supply, for use in an emergency lighting situation and wherein the second lighting unit is provided with a switch unit arranged to supply the command, depending on whether the emergency lighting situation occurs or not, directly from the bus connection or via the controller, respectively, to the internal lighting unit.

5. A lighting system according to any one of the preceding claims, wherein the control unit is arranged to simultaneously direct the command to a plurality of the first and second lighting units, including the internal lighting unit, for power setting and adjusted power setting respectively.

6. A lighting system according to any one of the preceding claims, wherein the second lighting unit is arranged to

- determine the intensity reference by calculating a fraction of a maximum contribution to the lighting of the location independently attainable by the second lighting unit, wherein a magnitude of the fraction is determined by the power setting from the command, and

- calculate an adjusted power amount for use in the second lighting unit, which is sufficient to raise the light level at the location to above the fraction.

7. A lighting system according to claim 6, provided with a memory for storage of information about a level of the maximum attainable contribution.

8. A lighting system according to claim 6 or 7, wherein the adjusted power amount is adjusted, at least around a value of the light level measurement where this value is equal to the intensity reference, with an essentially continuous derivative as a function of the light level measurement.

9. A lighting system according to any one of the preceding claims, wherein the second lighting unit is arranged to reduce, by means of the power amount, upon increase of the contribution to a light level of the location from outside the second lighting unit, a further contribution to the light level of the location by the second lighting unit to a smaller exte nt than the increase, at least until the contribution from outside the second lighting unit exceeds the intensity reference.

10. A lighting system according to any one of the preceding claims, wherein the second lighting unit is provided with a sensor operating in combination with the light meter, wherein the second lighting unit is arranged to adjust the control depending on a signal from the sensor.

11. A lighting system according to claim 10, wherein the sensor is a motion detector and/or other presence or absence detector and/or a remote control and/or a push button.

12. A lighting unit for use as second lighting unit in a lighting system according to any one of the preceding claims, provided with a bus connection, a controller, a light meter and an internal lighting unit, wherein the controller is coupled to the light meter and further between the bus connection and the internal lighting unit and is arranged to determine, from a controlled power setting in a command from the bus connection, an intensity reference for controlling the power used in the internal lighting unit for lighting, depending on a contribution of light coming from outside the internal lighting unit.

13. A lighting unit according to claim 12, wherein the controller is arranged to calculate an adjusted power setting in response to the command, as part of the control, and to send a changed command to the internal lighting unit, in which the adjusted power setting has been included.

14. A lighting unit according to claim 12 or 13, provided with a lighting mains connection, wherein the bus is arranged for delivering supply to the internal lighting unit and wherein the lighting mains connection feeds the controller and/or the light meter.

15. A lighting unit according to claim 12, 13 or 14, wherein the internal lighting unit is provided with an emergency supply, for use in an emergency lighting situation and wherein the lighting unit is provided with a switch unit arranged to supply the command, depending on whether the emergency lighting situation occurs or not, directly or after change by the controller, respectively, to the internal lighting unit.

16. A lighting unit according to claim 12, 13, 14, or 15, wherein the controller is arranged to determine the intensity reference by calculating a fraction of a maximum contribution to the lighting of the location which is independently attainable by the internal lighting unit, wherein a magnitude of the fraction is determined by the power setting, and by calculating an adjusted power amount sufficient to raise the light level at the location to above the fraction.

17. A lighting unit according to claim 16, provided with a memory for storage of information about a value of the maximum attainable contribution.

18. A lighting unit according to claim 16, wherein the adjusted power amount is adjusted to at least around a value of the light level measurement where this value is equal to the intensity reference with an essentially continuous derivative as a function of the light level measurement.

19. A lighting unit according to claim 16, wherein the controller is arranged to determine the adjusted power amount such that the light level at the location is at least equal to the intensity reference, and that the adjusted power setting decreases according as the contribution from outside the second lighting unit increases.

20. A lighting unit according to any one of claims 12 to 19, provided with a sensor operating in combination with the light meter, wherein the second lighting unit is arranged to adjust the control depending on a signal from the sensor.

21. A lighting system according to claim 20, wherein the sensor is a motion detector and/or other presence or absence detector and/or a remote control and/or a push button.

22. A method for installing a lighting system according to claim 1, wherein information about a maximum attainable contribution of the second lighting unit to a location lighted by the second lighting unit is programmed location-dependently.

23. A method for lighting a building under control of commands which are sent via a bus to lighting units, wherein a same command or type of command with a power setting is used by a first part of the lighting units as a command for controlling the respective lighting units on the power setting and is used in a second part of the lighting units as a command for controlling the lighting depending on a light level measurement, wherein the power setting from the command is used for calculating an intensity reference for the control.