GB2267585A

GB2267585A - Lighting control systems

Info

Publication number: GB2267585A
Application number: GB9311342A
Authority: GB
Inventors: John Woodnutt
Original assignee: Delmatic Ltd
Current assignee: Delmatic Ltd
Priority date: 1992-06-02
Filing date: 1993-06-02
Publication date: 1993-12-08
Also published as: GB9311342D0

Abstract

Switching modules 12A, 12B etc. control the lighting in respective areas in response to a control signal from a floor controller 10. On receipt of the common control signal each switching module initiates a switching routine which first gives a warning by dimming or selectively switching the lights and then effects a delayed switch-off. A user in an area receiving the warning can inhibit the switch-off by a message from one of the telephones 15A, 15B... to the telephone interface unit 11 identifying the area in which the lights are to remain on. To prevent overload of the telephone system the switching modules have different in-built delays to stagger the switching routines. <IMAGE>

Description

LIGHTING CONTROL SYSTEMS The present invention relates to lighting control systems for installation in offices and other buildings in order to switch-off the lighting of the whole building or of substantial parts thereof off manually or automatically at the end of the day. It is necessary when the lighting is to be switched off to give a warning to the remaining occupants and allow time for them to leave or to signal that the lighting for their area is to be left on.

Our European Patent Specification No. 0094166-A1 describes a lighting control system of this kind in which local switch units are provided in individual areas within the zone whose lighting is to be controlled. The occupant of any area can then use the local switch unit to transmit a signal to the zone controller to inhibit switching-off of the lighting in the local area.

The installation of local switch units connected to the zone controller involves extra work and expense and may be particularly difficult in large open-plan zones in which individual working areas whose lighting can be independently controlled are not divided from one another by walls or partitions. The present invention therefore relates to the use of the telephone system for transmitting inhibit messages to the lighting control system.

In accordance with the invention a lighting control system includes a plurality of switching modules controlling the lighting of different areas within a zone, a common controller connected to the switching modules of that zone whereby switching-off the lighting of all areas can be effected after issuing a warning by modification of the lighting in each of the areas and a telephone interface unit associated with the common controller to inhibit switching-off of the lighting in selected areas in response to telephone messages received from those areas.

To avoid overloading of the telephone system or the need for several parallel inputs to the telephone interface unit the warnings for the different areas within a zone are spaced in time. This can be done by arranging the controller to transmit individual warning signals to the switching modules in sequence.

Preferably however a single warning signal is transmitted to all the switching modules of a zone and each switching module has a different in-built delay.

In either case the warning, in the form of a brief interruption or dimming of the lighting, occurs at different times in different areas and the number of occupants simultaneously trying to call the interface unit is minimized.

All that is necessary is for the occupant of a particular local area to dial a code which identifies the area in which switch-off is to be inhibited.

The system may be designed to respond to "inhibit" messages only after the warning has been given to the first area in a zone but then to respond to messages from any of the areas in the zone. In this way an occupant of one area can react to the warning signal in an adjacent area and send the necessary "inhibit" message to the control system.

The invention will be described in more detail with the aid of an example shown in block diagram form in the accompanying drawings, in which: Figure 1 shows the overall layout of a lighting control system in accordance with the invention; and Figure 2 shows one of the switching modules of Fig. 1 in more detail.

Referring first to Fig. 1, a floor controller 10 is shown which is connected through a telephone interface unit 11 to a series of switching modules 12A, 12B, 12C.... The floor controller 10 receives an input from a central controller for the whole building and operates to control its own zone of the building, which in this case is one floor. The floor is sub-divided into local areas each of which has its own switching module 12 for controlling the local lighting circuits for that area. Each of the switching modules 12 is programmed to have its own specific address with which is associated a particular delay in the operation of the lighting circuits in response to receipt of an OFF signal from the floor controller 10. Thus when an OFF signal is transmitted by the floor controller it results in warning modification of the lighting at different times in the various local areas.Typically there can be a delay of eight seconds between the successive warnings in different areas.

Once the OFF signal has been received by a module from the floor controller, the module itself carries out the switch-off routine which includes the warning change in the lighting after a pre-programmed delay, followed by the switch-off of the lighting after a further delay. At any time after the OFF signal has been received by the module it is possible to cancel this switch-off routine by the transmission of an ON signal to the module.

The telephone interface unit 11 is connected to one extension socket 13 of a standard PBX 14 which is also connected to telephones 15A, 15B, 15C through extension sockets 16A, 16B, 16C Each of the telephones 15 is located in one of the local areas controlled by the switching modules. For example telephone 15A may be in the area whose lighting is controlled by switching module 12A. When the warning is given in this area by dimming of the lights or repeatedly switching them on and off, an occupant who wishes to continue working in that area and therefore wants the lights to remain on will use the telephone 15A to dial the extension 13 and then the code for the module 12A. The interface unit 11 will then transmit an ON signal to the switching module 12A, thereby cancelling the switch-off routine at that module.

The interface unit or the PBX unit itself can be arranged to identify the telephone 15 from which a code is received which requires that the lights stay on. The ON signal can then be transmitted to the module for the area in which the telephone is located. This simplifies the dialling procedure for the user.

Referring now to Fig. 2 the switching module 12A is shown, it being understood that the other switching modules are similar.

The input signal from the telephone interface unit 11 is applied to a terminal 18 and passes by way of a decoder 18 and a delay device 19 to a control unit 20. The delay imposed on the incoming signal by the delay device 19 is pre-set by an address-setting device 21. Thus an OFF signal transmitted simultaneously to all the switching modules reaches the control unit 20 of each switching module 12 with a delay which is determined by the address-setting device 21 of that module. The control device will then carry out a switching routine first to give a warning by dimming the lights or switching off some of the lights in the area controlled by that module and secondly, after a suitable delay which may be the same for all modules, switching off the lights.The second stage can be inhibited by a telephone switching signal, i.e. the ON signal from the interface unit 11, passed to the control unit 20 from the decoder 18 by way of line 22.

In some systems the switching-off sequence is only required to be inhibited or cancelled in a single module corresponding ta the telephone from which the ON message originates. In such a case each module will have a unique identification or address number which determines a different delay for each module. If a single telephone is to control a number of modules, the telephone address will determine which modules are to receive the ON signal but with a unique identification number for each module the delays will be different for each of several modules serving an area associated with the telephone address. Preferably however the telephone address is used by the address-setting device 21 to set all the modules serving that area to the same address with the same delay, thus ensuring that they operate simultaneously.

Claims

1. A lighting control system including a plurality of switching modules controlling the lighting of different areas within a zone, a common controller connected to the switching modules of that zone whereby switching-off the lighting of all areas can be effected after issuing a warning by modification of the lighting in each of the areas, and a telephone interface unit associated with the common controller to inhibit switching-off of the lighting in selected areas in response to telephone messages received from those areas.

2. A lighting control system as claimed in claim 1 in which the common controller and switching modules are constructed and arranged to provide the warning in different areas at different times.

3. A system as claimed in claim 2 in which each switching module has a pre-settable delay unit and the common controller issues a single warning signal to all the modules which is then delayed by different amounts.

4. A system as claimed in any of claims 1 to 3 in which each switching module is designed to respond to a common control signal from the controller by initiating a switching sequence which first provides the warning and then effects the switch-off for the corresponding area.

5. A system as claimed in any of the preceding claims in which each swicthing module includes a decoder responsive to a telephone signal identifying that module to inhibit switch-off of the lighting by that module.