It is a common tendency at present to have as much compliance and versatility as possible in the control of lighting. There are prior known control systems, which include one or more centralized control devices or controllers for lighting, and these, on the other hand, control the operation of dimmers or controllable electronic ballasts attached thereto. In systems like this, the dimmers are arranged in separate clusters or channels, wherein the dimmers of each channel perform the same control function, for example by adjusting to each desirable level of lighting. The centralized controllers have also been provided with operating devices or actuators, whereby the system can be subjected to human commands. These may include switching the lights on or off, bringing the lighting continuously in a desired direction, or switching onto a desired, pre- programmed level of lighting. These actuators may comprise for example sets of push-buttons or rotary potentiometers installed in a space to be illuminated.

Some of the actuators can be used for feeding desired function parameters (e. g. information about illuminance) into the system. One control system operating this way has been described in the Applicant's patent Fl 74828, wherein a common analogic control bus can be fitted with a plurality of control potentiometers for a so-called multipoint control.

Digital bus systems will be highly significant in the future in the process of integrating elements of lighting systems. The IEC technical committee TC 34 is in the process of working out a standard proposal regarding a digital control interface for lighting equipment. This definition will be included in the performance standard IEC 60 928 for electronic ballasts. Upon completion of

the standard, it will be possible for the first time to have combinations of ballast and controller products from various manufacturers in a common system.

It is a limitation to the above-described lighting control system that the system configuration must be largely decided as early as in the installation stage. If the intended use or geometric layout of a space to be illuminated changes due to the relocation of wall structures, for example, it is usually unavoidable that the system configuration be also changed by physically rearranging the actuators, by fitting the system with new service points, or by reclustering the control devices. Generally, this cannot be managed merely by programming the system in a new way, but the physical cable layout must also be rearranged. It is natural that this impedes the implementation of changes and incurs considerable expenses.

It is possible to increase functional compliance by decentralizing the system intelligence, i. e. by allocating logical functions of the system to dimmers or electronic ballasts, which serve as inputs for light sources of the system, i. e. lamps. Thus, the system is less dependent on the physical cable layout connecting its elements, and it is possible to implement a majority of changes by reprogramming a smart control unit set in the vicinity of a light source. This type of solutions have been described, among others, in the Patent application FI 8942012 and in the Patent EP 0 490 329. The functional intelligence can also be vested in the ballast unit of a lamp, as disclosed in the Patent Fl 96471.

On the other hand, the Applicant's Patent FI 94204 discloses a control device for lighting, which is intended for performing lighting control on the basis of the illuminance of an ambient space. Such a control unit can be included in each individual lighting fixture in the system for providing, for example, a variable, daylight-compliant lighting in spaces where the reduction of energy consumption by lighting is desirable. For example, the exploitation of natural light coming in through windows has proved to be quite a demanding task in terms of preferably maintaining a sufficiently constant illuminance on various surfaces of a space to

be illuminated. This is due to the fact that changes occurring in natural light may be major phenomena simultaneously both in terms of the dynamics and speed thereof, such as the sun being blocked by a cloud. Thus, it is very disturbing from the viewpoint of a person present in a space to be illuminated, if the level of lighting cannot be conditioned at a sufficient precision or if the lighting control measures performed by the system are unsatisfactory in terms of the speed or efficiency thereof (e. g. lights on/off repeatedly). Typically, this type of systems include a plurality of sensors intended for the measurement of lighting, some measuring e. g. natural light and some the aggregate light consisting of natural light and artificial light. The sensors have traditionally been mounted on wall surfaces in rooms. On the other hand, the system control unit houses a logic circuit for determining the necessary control measures proportional to the relationship of artificial light and natural light. The control unit delivers control commands for dimmers and electronic ballasts or strives to limit the share of natural light, e. g. by controlling shutters. Said control measures are based on quite a complicated control algorithm.

At any rate, the above-described systems must be adapted in each case to function in a desired manner by providing the system's logic unit with necessary setting parameters. The Applicant's patent application FI 981430 has dealt with this problematic situation and introduced a solution, wherein it is possible to focus said programming measures, i. e. the system encoding, on a precisely limited portion of a lighting system.

The use of such above-described lighting systems involves a problem that the optimal choice of a site for a sensor (a so-called constant light sensor) used for the measurement of a level of lighting is difficult, or the control algorithm for a unit constituting the logic control is complicated and, on the other hand, a compliant lighting system requires a wide variety of control and operating devices, which, in the worst case, must be individually connected and cabled one by one to the system. Such devices include, for example, operating push- buttons and presence sensors for detecting the presence of a person in a space

to be illuminated. It is generally known to employ an infrared signal or radio waves for the transmission of control and encoding data from actuators to the logic control units of a system. Such transmitters are useful, particularly when the system operator is physically moving in a space to be illuminated and has no desire to be compelled to use actuators permanently cabled to the system. It is highly typical for small infrared transmitters and similar units in office use that, when set e. g. on top of office desks, such units are often covered by other articles (e. g. papers). Consequently, the system operator is usually forced to manually pick up said actuator and to point it toward the system receiver for giving desired control and encoding commands to the system.

This invention introduces a simple control device for a lighting system for the transmission of control or encoding measures, as well as illuminance data. The invention enables also a sensor intended for the measurement of lighting intensity to be positioned as optimally as possible in terms of the system operation. At the same time, this eliminates the above-described problem about usually needing a plurality of said control devices and about impeding the operation of a control device by other articles on top of the device, for example by sheets of paper common in an office environment. Another problem that is resolved is the fact that the feed of operating voltage to a portable or movable control device merely by means of batteries or rechargeable accumulators is quite unreliable and often quite expensive with regard to its operating costs.

The invention is characterized by what is set forth in the annexed claim 1.

It is typical for the invention to combine a number of control devices (actuators) unavoidable in a compliant lighting system and a light sensor for a single unit, the connection of which to a lighting control system is effected by means of an infrared or radio link. The optimal location or site for the lighting-compliant light sensor of the system is on a surface whose level of lighting is to be maintained constant, i. e. generally e. g. on top of an office desk. In the control device for a lighting system of the invention, the unit is constructed in such a way that it

houses the above-mentioned service elements and is intended for use particularly on a desk, which makes it easy for the operator to perform desired control measures and, on the other hand, the light sensor is conveniently in the vicinity of the desk top and is thereby capable of measuring as optimally as possible the lighting intensity of a target to be illuminated. The unit has its power supply arranged by means of batteries, rechargeable accumulators or a photocell-based power source or a combination thereof. Of course, it is also possible to plug the unit to the power supply mains. The service unit can be designed conveniently in such a way that it cannot be normally covered by foreign objects, whereby the light measuring function or communication with the rest of the system over the infrared link is not jeopardized. The use of an infrared or radio link is preferred, as this makes it simple to provide a desired directional effect for the radio signal. Some configurations suitable for the invention are depicted in the accompanying drawings.

The invention will be described in more detail with reference to Fig. 1, Fig. 2, Fig. 3, and Fig. 4 of the drawings, wherein Fig. 1 shows a fundamental design for a lighting control system, comprising a variety of intelligent control devices, actuators therefor, light sources, and electronic ballasts therefor Fig. 2 shows logical nodal points for a lighting control system, and a basic design for a transmitter used for the control or encoding thereof Fig. 3 shows one configuration for a service unit provided with a control transmitter Fig. 4 shows another preferred mechanical design for a service unit provided with a control transmitter The control system shown in fig. 1 is provided with an infrared receiver 1 for

receiving control commands from a control transmitter 25, included in a portable service unit 2 and fitted with a constant light sensor 23 which supplies the system with a status signal proportional to the illuminance of a space to be illuminated. A device 4 comprises a control potentiometer for a stepless control over the level of lighting. A switch 5 can be used for controlling the lighting in an on/off mode, and a unit 6 can be provided with a so-called presence sensor for detecting the presence of a person in a space to be illuminated. Devices 8 comprise controllable electronic ballasts for discharge lamps, having discharge lamps 9 connected therewith. The system may also include electronic dimmers or electronic transformers 10 for halogen lamps, along with lamps 11. The duty of a smart control unit 7 is to control or govern the ballasts and dimmers 8,10 in compliance with information received from the actuators 1... 6 and preprogramming of the unit.

Fig. 2 takes a closer look at a transmitter 12, the control element of which is a unit 13. A modulator 14 uses a unit 15 for providing the transmission signal with encoding or control information set by a unit 16. A control signal 17, which can be transmitted by an infrared beam or radio waves, reaches a receiver 18 which is connected to a control unit 19 for creating desired control signals at terminals 20 of the receiver 1, from which the control signals are transmitted to the smart control unit 7 of a bus to be controlled for configuring the same to execute desired control functions.

The service unit shown in fig. 3 comprises a pyramidal housing element 3, the bottom portion of which constitutes a solid footing 21 which maintains the service unit and its integral control transmitter 25 in a proper operating position, e. g. on a desktop, and which, by virtue of its design, precludes any blanketing effect by other articles. In addition, the rather heavy-duty design reduces the likelihood of the service unit being carried away from its operating space. A set of push-buttons 22 for the implementation of control and encoding functions is placed on one face of the pyramid. A light sensor section 23 may function symmetrically in the direction of all edges. Being part of the service unit. the

light sensor 23 will be positioned in a location which is measured for its level of lighting and which is desired to receive a correct amount of light. Thus, the light sensor 23 is used for measuring the light arriving at a site to be illuminated and, at a desired level of lighting, the site to be illuminated can be chosen by means of a free disposition of the service unit. A face 24 may be provided with solar panels, whereby it is possible to produce the operating power required by the unit. The transmitter 25 comprises an infrared transmitter or, optionally, a link operating on radio waves.

Fig. 4 depicts a service unit substantially different in terms of its design, which is nevertheless provided with functionally equivalent elements designated by the same reference numerals as in fig. 3. A housing 3,3a includes a bottom side 21, which constitutes a solid footing against a table top. The unit has a middle section which is of a sufficient height for the control devices and actuators mounted on its top side to rise a sufficient distance above the bottom side. The middle section of the unit housing should have such a height that the control transmitter 25 and/or the light sensor 23 have a distance of more than 7 cm, preferably more than 10 cm, from a bearing surface constituted by the bottom side 21. A curved and upward convex panel board 3a constitutes a part of the housing 3,3a, by means of which the panel board 3a is propped in an upwardly angled position. The panel board 3a has the top face of its middle or bottom section provided with an operating keyboard 22 for feeding control or encoding information into the system. In its top section, the panel board 3a has its top face 26 provided with the control transmitter 25 and the light sensor 23, the latter giving the illuminance data to be transmitted to a lighting system. Being a part of the service unit, the light sensor 23 will be positioned in a location which is measured for its level of lighting and which is desired to receive a correct amount of light. Thus, the light sensor 23 is used for measuring the light arriving at a site to be illuminated and, at a desired level of lighting, the site to be illuminated can be chosen by virtue of the service unit being relocatable. The top face 26 is also provided with a display 27, which in the present case is set between the keyboard 22 and the transmitter 25. The displav can be designed

e. g. by liquid crystal technology. In this embodiment as well, the service unit can be provided with solar panels 24, which constitute e. g. sidebands for the panel board 3a. In both embodiments, the housing 3 has a weight which is sufficient for holding the service unit 2 stationary on a desk top while operating the manual control elements 22.

It is self-evident for a person skilled in the art that the applicability of the invention is not limited just to the presently described configurations, but a multitude of other solutions are available for various applications. Hence, it is possible to combine functional blocks housed in the service unit, such as power supply or keyboards, as required by any particular application.