Pictograph-based method and apparatus for controlling a plurality of lighting loads

A lighting control system for multiple lighting loads includes a computer that displays a pictograph and a lighting control panel. The pictograph includes selectable representations of the lighting loads. A particular lighting load is controlled by selecting a lighting state such as "on" or "off" on the lighting control panel and selecting a representation of the particular lighting load on the pictograph.

BACKGROUND OF THE INVENTION 
The present invention relates generally to lighting control systems. More 
specifically, the present invention relates to a computer-based system for 
controlling power to multiple ac lighting loads. 
Lighting loads in a large office building are typically controlled from a 
central location by a computer programmed with proprietary software. The 
computer can be programmed to turn on all office lighting loads before the 
start of business and turn off all of the office lighting loads after 
business hours. In addition to scheduling the times at which the lighting 
loads are turned on and off, the computer can also be programmed to 
perform annunciation of load status, central monitoring and reporting to 
ensure that the building is operating as efficiently as planned. 
The computer typically interfaces with a plurality of transformer relays, 
which are located in junction boxes throughout the building. The computer 
can control each relay to apply or remove power from its associated 
lighting load and thereby turn its associated lighting load on or off. A 
lighting load can include a single light or multiple lights. The relays 
and, therefore, the lighting loads can also be controlled by wall-mounted 
switches and sensors distributed throughout the building. Such a system 
including a plurality of intelligent relay-based lighting control system 
is available from the General Electric Company under the names "Total 
Lighting Control" system and "TLC" systems. 
However, controlling the lighting loads from a central location can cause 
problems for those people who come to work early or work late into the 
night. When the computer turns off the lights, some of the people inside 
the building will be left in the dark. Naturally, they will want to turn 
the lights back on. However, turning the lights back on can pose more than 
a mild inconvenience. A person must set aside his work, walk over to the 
light switch and flip on the switch. In a large work area having many 
different lights, finding the correct switch can be a challenge. Some 
lighting control systems do not even allow the lights to be manually 
overridden. 
Instead, a facilities management is called and asked to turn the lights on. 
Hopefully the response will be prompt. 
There are phone-based lighting control systems that allow a person to turn 
on the lights by dialing up a certain number. These phone-based systems 
map each available lighting load onto a corresponding phone number. 
However, such artificial phone number mappings are non-intuitive. For 
instance, a person might be required to memorize or look up a twelve-digit 
phone number in order to use the phone-based lighting control system. For 
this reason alone, the phone-based systems tend to be cumbersome to use. 
Additionally, typical phone-based lighting control systems do not allow 
the intensities of the lighting loads to be varied. 
SUMMARY OF THE INVENTION 
The present invention can be regarded as a computer that can control a 
plurality of lighting loads quickly and conveniently. The computer 
includes a display and memory encoded with executable instructions. When 
executed, the instructions cause the computer to show a pictograph and a 
control panel on the display. The pictograph includes selectable 
representations of the lighting loads, and the control panel allows a 
lighting load state to be entered into the computer. When a representation 
on the pictograph is selected, the instructions cause the computer to 
generate a lighting control request. The lighting control request 
identifies a lighting load corresponding to the selected representation 
and the lighting control state entered into the computer. The lighting 
control request is used for controlling the lighting load corresponding to 
the selected representation. 
In one embodiment of the present invention, the computer is connectable to 
a computer network. This allows a person to control the lighting loads 
from the convenience of his or her desk.

DETAILED DESCRIPTION OF THE INVENTION 
As shown in the drawings for purposes of illustration, the invention is 
embodied in a lighting control system. The lighting control system allows 
distributed elements or Network Appliances connected to a computer network 
to control a plurality of lighting loads. Thus, a person can quickly turn 
lights on and off from the convenience of his or her desk. Moreover, the 
Network Appliances can include computers already connected to the network. 
Thus, the lighting control system can be expanded by using existing 
hardware. As a result, the lighting control system can be set up and 
expanded quickly and inexpensively. 
FIG. 1 shows a lighting control system 10 for a plurality of lighting loads 
12. The lighting loads 12 can be located in a facility such as an office 
building. A typical office building has multiple floors and lighting loads 
12 on each floor. There might be one or more lighting loads 12 per office, 
or there might be one lighting load 12 covering several offices. The 
lighting loads 12 are turned on and off by relays 14, which are wired to a 
power/communications bus 16. The relays 14 are controlled by wall-mounted 
switches 18 and other devices such as daylight sensors and occupancy 
sensors located in the offices and at various locations in the building. 
Turning on a switch 18 causes a relay 14 to turn on an associated lighting 
load 12. 
The relays 14 are also controlled by Network Appliances such as a Virtual 
Light Switch 20 and a web browser 22 connectable to a computer network 24. 
Typically, there would be more than one Virtual Light Switch 20 and more 
than one web browser 22. To simplify the description of the present 
invention, however, the lighting control system 10 will be described in 
connection with only one Virtual Light Switch 20 and only one web browser 
22. The Virtual Light Switch 20 and the web browser 22 generate first and 
second lighting control requests LR1 and LR2, which identify states (e.g., 
lighting intensities) of specific lighting loads. The first and second 
lighting control requests LR1 and LR2 are sent over a computer network 24 
to a server 26. The server 26, which might or might not be located in the 
same building as the lighting loads 12, receives the first and second 
lighting control requests LR1 and LR2 and responds by generating digital 
commands CMD. The digital commands CMD, which indicate the lighting load 
states indicated in the lighting control requests LR1 and LR2, are used to 
control the lighting loads 12. 
The digital commands CMD are sent to an interface module 28. The interface 
module 28 allows the server 26 to link into the power/communications bus 
16. Typically, the interface module 28 does not adhere to an open 
standard; instead, it expects the digital commands CMD to be in a 
proprietary format. Therefore, the server 26 generates the digital 
commands CMD in the proprietary format. The interface module 28 translates 
the digital commands CMD into analog relay commands ARC and places the 
analog relay commands ARC onto the power/communications bus 16. The analog 
relay commands ARC are received by all of the relays 14 coupled to the 
power/communications bus 16, but they control only specific relays 14. 
Thus, the analog relay commands ARC can control a specific relay 14 to 
turn on its associated lighting load 12, adjust brightness of its lighting 
load 12, etc. The interface module 28 also receives status signals on the 
power/communications bus 16. The status signals are placed on the 
power/communications bus 16 when, for instance, a light switch 18 is 
flipped on or off. Such relays 14, power/communication buses 16 and 
interface modules 28 are commonly used in lighting control systems. For 
example, the interface module 28 can be a TLC Dataline Communications 
Interface Module, which is available from GE Lighting Controls. 
The first lighting control request LR1 directly identifies a specific 
lighting load 12 and a state (e.g., lighting load intensity) for the 
identified lighting load 12. An exemplary first lighting load request LR1 
including header information, a bit field for an ID number and a bit field 
for a lighting load intensity (e.g., 0=off, 1=1/3 intensity) is 
illustrated in FIG. 1a. The first lighting control requests LR1 are 
generated by Network Appliances such as the Virtual Light Switch 20. The 
second lighting control request LR2 identifies a lighting load state and 
indirectly identifies a specific lighting load 12 by providing information 
about the lighting load 12. The information is later translated in order 
to directly identify the specific lighting load 12. As discussed below, 
the second lighting control requests LR2 are generated by Network 
Appliances such as the web browser 22. 
The computer network 24 can be anything from the Internet to a local area 
network ("LAN") using proprietary client-server software. The physical and 
link layers of the computer network 24 can be Ethernet, Token Ring or any 
other physical and link layer. The network layer can be Internet Protocol 
("IP") or any other network protocol. The transport layer can be Transport 
Control Protocol ("TCP"), User Datagram Protocol ("UDP"), or any other 
transport protocol. The session layer can be Hypertext Transport Protocol 
("HTTP"), File Transfer Protocol ("FTP"), "DCOM," "CORBA" or any other 
session protocol. Merely by way of example, the computer network 24 will 
be described as a LAN having an Ethernet backbone, and using TCP/IP and 
HTTP communication protocols. 
The server 26 includes a central processing unit 30, a network card 32 for 
communicating over the computer network 24, RAM 34, and a memory storage 
device memory (e.g., a hard drive) 36 encoded with data. The data includes 
an operating system 38, interface program 40, a lighting daemon 42, 
multiple HTML files 44, and multiple image maps 46. Each HTML file 44 and 
image map 46 corresponds to a floor plan of the facility. The data can be 
loaded onto the memory storage device 36 via a peripheral device 35 such 
as a CD ROM drive, electronically transferred to the memory storage device 
36 via the computer network 24, etc. 
Each HTML file 44 includes a set of tags (i.e., instructions) for the web 
browser 22. The web browser 22 can be a first personal computer 48 
including a central processing unit 50 and a network card 52 for 
communicating over the computer network 24. The first personal computer 48 
further includes a display 54, I/O devices 56 such as a mouse and 
keyboard, RAM 58 and a hard drive 60 encoded with an operating system 62 
and web browser program 64 such as "Netscape Navigator" or "Microsoft 
Internet Explorer." 
Additional reference is now made to FIG. 2. After the web browser 22 
downloads an HTML file 44 from the server 26, the web browser 22 stores 
the HTML file 44 in the RAM 58 or the hard drive 60 and begins executing 
the tags in the HTML file 44. The tags instruct the web browser 22 to 
download and display the image map 46 corresponding to the downloaded HTML 
file 44 and to create and display a lighting control form 66. The lighting 
control form 66 includes graphical display elements 68a, 68b, 68c and 68d 
such as radio buttons and checkboxes indicating pre-selected lighting 
states such as lighting intensities. FIG. 2 happens to show a first radio 
button 68a corresponding to an "off" state, second and third radio buttons 
68b and 68c corresponding to "1/3 intensity" and "2/3 intensity" and a 
fourth radio button corresponding to "full intensity." Using an I/O device 
56 such as a mouse, a lighting load state is selected by clicking a 
graphical display element 68a, 68b, 68c or 68d. The lighting control form 
66 could also include a text box (not shown) for entering a numerical 
value (or percentage) of lighting intensity. 
The downloaded image map 46 graphically shows selectable representations of 
the lighting loads 12. For example, the image map 46 shows a floor plan 70 
for the office building. When a first zone 72 on the floor plan 70 is 
clicked, the HTML file 44 instructs the web browser 22 to generate a 
second lighting control request LR2 identifying the lighting load state 
selected on the lighting control form 66 and information about (e.g., 
coordinates on the first zone 72. The HTML file 44 also instructs the web 
browser 22 to send the second lighting control request LR2 to the 
interface program 40 running on the server 26. A second lighting control 
request LR2 according to the HTTP protocol might include a GET command, 
the URL of the interface program 40 and a query string including the zone 
coordinates and the lighting load state. 
The interface program 40 can be a Common Gateway Interface (CGI) program, 
which listens on a server port for the second lighting control requests 
LR2 from the web browser 22. When a second lighting control request LR2 is 
received, the interface program 40 identifies the lighting load 12 
covering the first zone 72. The interface program 40 can use a lookup 
table to translate the zone coordinates into a lighting load identifier 
(e.g., a lighting load ID number). The interface program 40 can also 
perform access control to determine whether the web browser 22 making the 
second lighting control request LR2 is authorized to control the 
identified lighting load 12. 
The interface program 40 sends a first lighting control request LR1 
indicating the lighting load identifier and the lighting load state to the 
lighting daemon 42. In response, the lighting daemon 42 generates a 
digital command CMD for the interface module 28. The digital command CMD 
indicates the identified lighting load and lighting load state, but in a 
format expected by the interface control module 28. The interface module 
28, in response, translates the digital command CMD into an analog control 
signal ARC, which causes a relay 14 to turn on the identified light at the 
intensity indicated in the digital command CMD. 
Thus, clicking the second radio button 68b on the lighting control form 66 
and then clicking a first zone 72 of the floor plan 70 will cause the 
lighting load 12 covering the first zone 72 to be turned on to 1/3 
intensity. Clicking the first radio button 68a of the lighting control 
form 66 and clicking the first zone 72 again will cause the lighting load 
12 covering the first zone 72 to be turned off. 
The HTML file 44 could also generate a navigation bar 74 for linking to 
other floor plans. For example, clicking floor plan 1U on the navigation 
bar 74 would cause an HTML file 44 and image map 46 corresponding to floor 
plan 1U to be downloaded to the web browser 22. 
The lighting daemon 42 also makes network connections with the Virtual 
Light Switch 20 and listens on the server port for first lighting control 
requests LR1 directly from the Virtual Light Switch 20. The Virtual Light 
Switch 20 controls an assigned lighting load 12. The Virtual Light Switch 
20 can be a second personal computer 76 including a central processing 
unit 78, RAM 80, a disk drive 82, and a network card 84 for communicating 
over the computer network 24. The second personal computer 76 further 
includes a display 86 and I/O devices 88 such as a mouse and keyboard. A 
windows-based operating system 90 and VLS program 92 are stored on the 
disk drive 82. Unlike the web browser 22, which receives its instructions 
from the server 26, the Virtual Light Switch 20 receives its instructions; 
from the VLS program 92. If coded in the "Java" programming language, the 
VLS program 92 can be run on different platforms. When the instructions of 
the VLS program 92 are executed, the Virtual Light Switch 20 displays an 
icon (not shown) on the display 86. The icon represents the lighting load 
12 that is controlled by the Virtual Light Switch 20. The icon can 
indicate the current state of the assigned lighting load 12. For example, 
an icon that is only half lit might indicate a light intensity of 50%. 
When the icon is selected (for example, by positioning a cursor over the 
icon and clicking), a control panel 94 appears on the display 86 (see FIG. 
3). The control panel 94 includes graphical display elements 96a and 96b 
such as radio buttons, sliders and scrollbars for entering lighting 
intensities and other lighting states. Controlling a graphical display 
element 96a or 96b causes the Virtual Light Switch 20 to generate and send 
first light control requests LR1 over the network 24 in real time. Thus, 
the Virtual Light Switch 20 controls its assigned lighting load 12 in 
real-time. 
The first lighting control request LR1 from the Virtual Light Switch 20 
directly identifies its assigned lighting load 12 and a state (e.g., light 
intensity) for the assigned lighting load 12. The Virtual Light Switch 20 
can be preconfigured with the identifier for its assigned lighting load 
12. The Virtual Light Switch 20 can be configured manually by accessing an 
identifier from a configuration file on the server 26 and saving the 
identifier on the disk drive 82. In the alternative, the Virtual Light 
Switch 20 could automatically receive a lighting identifier from the 
server 26 upon connection. The server 26 could use a CGI script for 
generating the lighting load identifier. 
The lighting daemon 42 receives the first lighting control request LR1 on 
the network 24 and processes the first lighting control request LR1 by 
generating a digital command CMD for the interface module 28. The digital 
command CMD indicates the identified lighting load and lighting load 
state, but in the format expected by the interface control module 28. 
As previously mentioned, the Virtual Light Switch 20 can also display the 
status of its assigned lighting load 12. To enable each Virtual Light 
Switch 20 to display the status of its assigned lighting load 12, the 
lighting daemon 42 communicates with the interface module 28 and monitors 
the power/communications bus 16 for analog relay commands ARC. When a 
wall-mounted switch 18 is flipped, for example, an analog relay command 
ARC is placed on the power/communications bus 16 and sent to a relay 14 
associated with the wall-mounted switch 18. Via the interface module 28, 
the lighting daemon 42 detects the analog relay command ARC, generates a 
message including a lighting load identifier and the state of the light 
switch 18 affected by the analog relay command ACR, and multicasts the 
message to the Virtual Light Switch 20. Because the Virtual Light Switch 
20 is configured with a matching identifier, it updates its icon for the 
change in state of the assigned lighting load 12. 
For example, if the second personal computer 76 is located in a second 
zone, it might be configured to function as a Virtual Light Switch 20 for 
the lighting load 12 covering the second zone. The icon displayed on the 
display 78 of the second personal computer 76 would indicate the intensity 
of the lighting load 12 covering the second zone. Sliding a slider bar on 
the control panel 94 would cause the Virtual Light Switch 20 to generate 
and send first lighting control requests LR1 to the server 26 and to 
update the icon to indicate the changing intensities. Thus, moving the 
slider bar in one direction would cause a real-time increase in the 
intensity of the lighting load 12 covering the second zone and moving the 
slider bar in an opposite direction would cause a real-time decrease in 
the lighting load intensity. If a wall-mounted switch 18 for the lighting 
load 12 covering the second zone is turned off, the lighting daemon 42 
would detect the resulting analog relay command ARC and multicast a 
message. The Virtual Light Switch 20 assigned to the second zone would 
update its icon to indicate that the lighting load 12 covering the second 
zone has been turned off. 
FIG. 4 shows the flow control for the lighting daemon 42. The lighting 
daemon 42 is run on the server 26 in the background. When started (block 
100), the lighting daemon 42 performs initialization routines including 
logging onto the interface module 28 and establishing a connection with 
the interface module 28 (block 102). 
After a connection with the interface module 28 has been established, the 
lighting daemon 42 can optionally read all of the current relay settings 
to determine the initial states of the lighting loads 12 (block 104). The 
initial states are recorded. The lighting daemon 42 can determine the 
relay settings by broadcasting queries on the power/communications bus 16 
via the interface module 28 and then record the responses. Instead of 
determining the initial conditions of all of the lighting loads 12, the 
lighting daemon 12 could wait until a Virtual Light Switch 20 makes a 
connection with the server 26 and then determine and record the initial 
state of the connected Virtual Light Switch 20. In either scenario, the 
lighting daemon 42 would notify the Virtual Light Switch 20 of the initial 
lighting load state, thereby completing the connection. 
Next, the lighting daemon 42 waits for communications from the network 24 
and the interface module 28 (block 106). The lighting daemon 42 also waits 
for communications such as termination requests and first lighting control 
requests LR1 from the interface program 40. 
If the lighting daemon 42 receives a termination request from a source such 
as the system operator (block 108), the lighting daemon 42 performs 
clean-up tasks (block 110) such as shutting down or terminating 
connections with the Virtual Light Switch 20 (e.g., making the Virtual 
Light Switch 20 unresponsive), flushing persistent internal states to the 
storage device 36 (e.g., closing open files), and logging off the 
interface module 28. Then the light daemon 42 terminates (block 112). The 
termination requests might be generated in order to perform maintenance 
such as daemon and system upgrades. The termination requests might also be 
generated internally in response to hardware and software faults. 
If the lighting daemon 42 receives a first lighting control request LR1 
(block 114), the lighting daemon 42 optionally performs authentication or 
some other security check (block 115), generates a digital command CMD 
(block 116) and sends the digital command CMD to the interface module 28 
(block 117). The Virtual Light Switch 20 and the interface program 40 
would typically use the same protocol for communicating with the lighting 
daemon 42. After the lighting daemon 42 sends the digital command CMD to 
the interface module 28 (block 117), it waits for an acknowledgment from 
the interface module 28 (block 118). If the acknowledgement is not 
received (block 120) due to, for instance, a timeout or transmission 
error, the lighting daemon 42 resends the digital command CMD to the 
interface module 28 (block 117). If an acknowledgment is received (block 
120), the lighting daemon 42 resumes waiting for the next communication or 
message (block 106). 
If the lighting daemon 42 receives an analog relay command ARC from the 
interface module 28 indicating a change in state of a lighting load (block 
114), the lighting daemon 42 records the new state of the lighting load 12 
(block 122). Then the lighting daemon 42 multicasts a message to the 
Virtual Light Switch 20 affected by the change in light state (block 124) 
and waits for an acknowledgment from the Virtual Light Switch (block 126). 
If the acknowledgement is not received (block 128) due to, for instance, a 
timeout or transmission error, the lighting daemon 42 resends the message 
to the Virtual Light Switch 20 (block 124). If an acknowledgment is 
received (block 128), the lighting daemon 42 resumes waiting for the next 
communication or message (block 106). 
Functions such as waiting for and responding to first lighting control 
requests LR1 (blocks 106, 108 and 114 to 120), and monitoring and 
responding to changes in lighting load states (blocks 106, 108, 114 and 
122 to 128) are shown as being performed sequentially. However, these 
functions could be performed in parallel by appropriate hardware such as a 
Symmetric Multiprocessor Machine (SMP). Thus, a lighting daemon 42 running 
on an SMP could monitor and respond to lighting load changes at the same 
time it waits for and responds to first lighting control requests LR1. 
FIG. 5 shows steps for controlling a lighting load 12 via the web browser 
22. With the browser program 64 running on the first personal computer 48 
(step 200), a user enters the URL of the HTML file 44 (step 202) 
corresponding to the floor plan. This causes the web browser 22 to 
download the HTML file 44 from the server 26 (step 204). The web browser 
22 begins executing the HTML file 44 (step 206), generating and displaying 
the lighting control form 66 and downloading and displaying the image map 
46 corresponding to the HTML file 44 (step 208). The user clicks a radio 
button indicating a light intensity (step 210) and then a zone 72 of the 
floor plan 70 (step 212). When the zone 72 is clicked on, the web browser 
22 generates and sends a second lighting control request LR2 to the 
interface program 40 (step 214). 
The interface program 42 is invoked to determine the zone coordinates and 
light state indicated by the second lighting control request LR2 (step 
216) and translates the zone coordinates into a lighting load identifier 
(step 218). Then the interface program 40 generates a first lighting 
control request LR1 indicating the lighting load identifier and lighting 
load state (step 220), and sends the first lighting control request LR1 to 
the lighting daemon 42 (step 222), which is already running on the server 
26 (step 215). 
In response to the first lighting control request LR1, the lighting daemon 
42 generates a digital command CMD for the interface module 28 (step 224). 
The interface module 28, in turn, generates an analog relay command ARC 
and multicasts the analog relay command ARC on the power/communications 
bus 16 (step 226). The analog relay command ARC is received by many of the 
relays 14, but only the relay for the lighting load covering the selected 
zone is controlled according to the requested lighting load state (step 
228). 
FIG. 6 shows steps for controlling a lighting load 12 via a Virtual Light 
Switch 20. By way of example, the Virtual Light Switch 20 controls an 
overhead light 12. The VLS program 92 is executed on the second personal 
computer 76 (step 300). The Virtual Light Switch 20 displays the icon on 
the display 86 (step 302) and initiates a connection with the lighting 
daemon 42 (step 304), which is already running on the server 26 (step 
306). The lighting daemon 42 determines the current state of the overhead 
light 12 (step 308), and multicasts a message indicating the current state 
on the computer network 24 (step 310). The Virtual Light Switch 20 for the 
overhead light 12 receives the message and updates the icon to indicate 
the current state of the overhead light 12 (step 312). 
When the user selects the icon (step 314), the control panel 94 is shown on 
the display 86 (step 316). Each time the user moves a graphical control 
96a or 96b on the control panel 94 (step 318), the Virtual Light Switch 20 
generates a first lighting control request LR1 indicating the light 
identifier for the overhead lighting load and the light state for the 
overhead lighting load 12 (step 320). The first lighting control request 
LR1 is sent to the server 26 (step 322). 
The lighting daemon 42 receives the first lighting control request LR1 
(step 324) and generates a digital command CMD for the interface module 28 
(step 326). The interface module 28, in turn, generates an analog relay 
command ARC for the power/communications bus 16 (step 328). The analog 
relay command ARC is received by many of the relays 14, but only the relay 
14 for the overhead lighting load 12 is controlled (step 330). 
Thus disclosed is a lighting control system 10 that allows lighting loads 
12 to be controlled from the convenience of a computer. No longer is it 
necessary to walk over to a wall-mounted switch 18 or rely upon facilities 
management to control the lighting loads 12. Additionally, energy is 
conserved because the lighting control system 10 makes it easier to turn 
off the lighting loads and, therefore, makes it less likely that a person 
would leave the lighting loads on after leaving the office. Some people, 
especially those in a rush to leave the office, do not want to be burdened 
with the chore of turning off the lighting loads. 
The lighting control system 10 makes use of existing 
infrastructure--computers and networks. Therefore, the lighting control 
system 10 can be implemented and expanded quickly and inexpensively. 
The lighting control system 10 even allows the lighting loads 12 to be 
controlled outside of the facility, from a remote location. If a person 
can't remember whether the lights were left on in his office, he could 
dial into the computer network 24 using a modem or ISDN line on his home 
computer, download the appropriate HTML file 44 or run a VLS program 92 on 
his home computer, and turn off the lighting loads in his office. 
The lighting control system 10 is applicable to any facility having 
centralized control of the lighting loads. For example, the lighting 
control system 10 could be applied to small businesses, schools and homes. 
Therefore, the lighting control system 10 is not limited only to office 
buildings. 
The invention is not limited to the specific embodiments described above. 
For example, the lighting control form 66 can include graphical display 
elements for controlling lighting characteristics other than light 
intensity. If multiple lights cover a single zone, the lighting control 
form 66 can also include graphical display elements for controlling 
specific lights. For example, the lighting control form 66 might allow a 
selection of different colored lights (e.g. red and blue lights) or lights 
at different levels (e.g. upper and lower lights). Therefore, the 
selections on the lighting control form 66 ultimately depend upon the 
number and types of lights being controlled. 
As another example, the image maps 46 are not limited to static image maps. 
Instead, dynamic image maps could show current lighting load states for 
each of the zones. A lighting state could be represented by showing a zone 
in a shade of gray or yellow. Additionally, the dynamic image maps could 
be updated for changes in lighting load states. Dynamic image mapping 
could be implemented via dynamic HTML, a CGI program and the lighting 
daemon 42. 
Yet another example is shown in FIG. 7. The HTML file 44 can utilize an 
applet 98 (see FIG. 1) for creating the image map 46 and displaying the 
lighting control form 66 instead of having the HTML file 44 create and 
display a lighting control form 66. The HTML file 44 includes an applet 
tag. A Java-enhanced web browser downloads the HTML file 44 (step 400), 
recognizes the applet tag (step 402), downloads the applet 98 (which is 
identified by the applet tag) (step 404) and begins executing the applet 
98 (step 406). When executed, the applet 98 instructs the Java-enhanced 
web browser to display the lighting control form 66 (step 408) and 
download and display a pictograph of the floor plan (step 410). When a 
lighting load state is entered and a zone on the floor plan is selected 
(step 412), the applet 98 identifies the lighting load covering the 
selected zone (step 414), generates a first (not second) lighting request 
LR1 indicating the identified lighting load and the light state (step 
416), and sends the first lighting control request LR1 directly to the 
lighting daemon 42 (step 418). Thus, the applet 98 bypasses the interface 
program 40. Moreover, the applet 98 allows a greater selection of controls 
(e.g., sliders and scrollbars) for entering the intensity and other 
characteristics of the lighting loads 12. A web browser that is not 
Java-enhanced would simply ignore the applet tag and, instead, download an 
image map 46 and create and display a lighting control form 66 as 
instructed by the other tags in the HTML file 44. 
Instead of utilizing an applet 98, the HTML file could utilize JavaScript 
scripting or Active-X controls. A web browser that is not JavaScript 
scripting or Active-X enabled would simply display a lighting control form 
66. 
Instead of using CGI scripting for the interface program 40 program, the 
interface program 40 could be implemented by programs written in a native 
language such as C++. Moreover, the interface program 40 is not limited to 
CGI. Rather, the interface program 40, if used, could be any program that 
allows the server (or another computer) to translate the zone coordinates 
into lighting load identifiers. 
The invention is not limited to an image map 46 of a floor plan. Rather, 
the invention can use any pictograph that allows lighting loads 12 to be 
identified and selected. 
The lighting daemon 42 could be run on the same server 26 as the interface 
program 40 or it could be on a different server. If the lighting daemon 42 
is run on a different server, the interface program 42 would relay the 
first lighting control request LR1 to the server on which the lighting 
daemon 42 is running. 
The lighting daemon 42 can retrieve the first lighting control requests LR1 
by means other than by listening to ports. For example, the lighting 
daemon 42 could receive tokens. 
The lighting daemon 42 is not restricted to run on any particular operating 
system. Although the term "daemon" is associated with the Unix paradigm, 
the lighting daemon 42 is a lighting control program that can be adapted 
for any operating system. In the Novell paradigm, the lighting daemon 42 
might be referred to as a lighting "network loadable module" or "NLM." 
The invention is not even limited to a server 26 and computer network 24. 
For example, FIG. 8 shows a lighting control system 500 in which a single 
controller 502 controls multiple lighting loads 504 via an interface 
module 506, multiple relays 508, switches 509 and a power/communications 
bus 510. The controller 502 can be a personal computer having a central 
processing unit 511, a display 512, memory 514 and an I/O port 516 for 
interfacing with the interface module 506. Encoded in the memory 514 is a 
standalone program including a plurality of instructions 518. When 
executed, the instructions 518 cause the controller 502 to display a 
pictograph and control panel on the display 512. The pictograph includes 
representations of the lighting loads 504. When a lighting load state is 
entered into the controller 502 and a representation on the pictograph is 
selected, the controller 502 generates digital commands for the interface 
module 506. Unlike the server 26 above, the controller 502 does not 
receive lighting control requests via a computer network. 
FIG. 9 shows a method in which the controller 502 controls multiple 
lighting loads 504 in an office building. When the instructions 518 are 
executed, the controller 502 displays a first pictograph showing different 
floor plans (block 600). When a floor plan is selected (602), the 
controller 502 displays a second pictograph of the selected floor plan 
(block 604). The controller 502 also displays a control panel (block 606). 
When a lighting load state is entered into the control panel (block 608) 
and a zone on the floor plan are selected (block 610), the controller 502 
identifies the lighting load 504 covering the selected zone (block 612) 
and generates a digital command for the identified lighting load 504 
(block 614). The controller 502 sends the digital command to the interface 
module 506 via the I/O port 516 (block 616). The interface module 506, in 
response, generates an analog relay command for the power/communications 
bus 510 (block 618). The relay 508 associated with the identified lighting 
load 504 responds to the analog relay command by controlling the 
identified lighting load 504 (block 620). 
The Network Appliances 26 are not limited to Virtual Light switches 20 and 
web browsers 22 that are based on personal computers. Other types of 
Network Appliances 26 could include personal digital assistants (PDAs), 
cell phones, calculators and information appliances such as smart 
toasters. 
These considerations, along with other considerations such as the design of 
the computer network, are left to the discretion of the designer of the 
lighting control system and the application for which the lighting control 
system is intended. 
Therefore, although the specific embodiments of the invention have been 
described and illustrated, the invention is not limited to the specific 
forms or arrangements of parts so described and illustrated. The invention 
is limited only by the claims that follow.