Abstract:
An improved occupancy detection and load management system wherein a plurality of scout sensors and their surrogates may be networked to a master controller to control the load of a designated control zone. When occupancy is detected by an actual sensor or a sensor surrogate, scout sensors report only that event and each event, regardless of source, has the potential to initiate or sustain the occupied state of the master controller. As a zone becomes unoccupied, event reports stop being sent allowing the master controller to time out and exit its occupied state. Loss or addition of scout sensors does not affect operation as the master does not track individual sensors which additionally allows event reports to be created and sent by plurality of sources including momentary contact buttons, user controls, personal computers, and other building automation systems like fire alarms, security, and access control.

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates primarily to occupancy based load management systems for lighting, plug-load, and similar loads being managed to reduce energy use or to provide response to emergency and security inputs. 
     2. Description of the Related Art 
     Prior art occupancy based load management is based on onymous or named communication between an occupancy detection sensor and a zone controller. These two components determine if a zone is occupied and then modulate a connected electrical load accordingly. The basic operation of this communication was worked out over 20 years ago. A sensor detects motion, sound or another proxy for human presence and then communicates that status to a load controller that has traditionally been a relay. 
     Conventional Occupancy logic switches on the connected load when a zone becomes occupied and switches off that load when the zone becomes unoccupied. With more recent Vacancy logic the auto-off step is retained but the load is turned on manually. In actual operation, occupancy detection is often spotty so a delay timer is added to smooth out the process by creating a window of time during which the detected occupancy will reset the delay timer to keep the lights on. 
     The above process can also be described in terms of states. The zone starts in an unoccupied or idle state and changes to an occupied state when occupancy is detected. If the sensor is configured for occupancy logic there is an action associated with the state change to switch on the connected load. If vacancy logic is being used the load is assumed to be turned on manually. The occupied state continues until the occupied state timer times out. This timer is set to its timeout period each time that an occupancy proxy event is detected. If no proxy event is detected the timer times out and the auto-off process begins. 
     Multi-Sensor Operation—When zones are too large for a single sensor, multiple sensors are typically used to cover the space. The conventional solution has been to parallel wire multiple stand-alone sensors to a single load controller. When any one sensor detects presence and trips (changes from its idle to occupied state) it closes an internal switch which activates the controller. If the controller is a relay, the relay solenoid activates which then closes the relay and switches on the connected load. As more sensors detect occupancy, they also trip but no additional action occurs because the zone is already in the occupied state. However, as the zone becomes unoccupied all the parallel wired sensors must return to their idle state before the zone becomes fully unoccupied and the electrical load is allowed to turn off. In Boolean logic terms the on function is an OR gate and the off function is an AND gate. 
     The parallel wired approach has worked well but is cumbersome and restrictive. Parallel wired sensors require long cable runs and 3-wire polarized connections that can be miss-wired. They also have limited capacity due to available power of the controller. Power limits can be addressed by power boosters but in larger rooms and corridors there is little that can be done about long cable runs. Additionally, adding additional sensors or making other changes to the zone operation require rewiring and each sensor adjustment must be made manually at each sensor. In small applications these limitations are likely not significant but in larger buildings the act of individually maintaining hundreds and even thousands of sensors can be overwhelming. 
     Networking sensors together has the potential to addresses these problems. However, as occupancy sensors have been adapted to networking, much of their operation has not changed. Prior art networked sensors continue to operate as independent devices and act as if they were parallel wired. In order to make this work the zone controller must know how many sensors are covering a zone and must then keep track of the state of each sensor. This is done with an onymous communication from each sensor that is sent each time the sensor changes state. 
     To avoid these problems U.S. Pat. No. 8,009,042 B2 limits the number of sensors allowing the sensors and zone controller to be preconfigured. Zones with a variable number of sensors can be supported but only by offering products that are preconfigured for varying number of sensors or by providing some form of field configuration to set up the zone for a fixed number of sensors. 
     U.S. Pat. No. 8,009,042 B2 also acknowledges another problem with prior art networked sensors wherein the loss of any sensor in the occupied state will prevent the virtual circuit from clearing and returning to the unoccupied state. U.S. Pat. No. 8,009,042 B2 addresses this problem by adding a heartbeat function to detect any missing sensors but the fundamental problem caused by state-based logic remains. 
     Thus, what is needed is a new approach. Advanced lighting control systems with sophisticated interactive occupancy detection, daylighting, and user control are becoming increasingly common due to their capacity to significantly reduce energy use and to deliver an enhanced work environment. However, as these systems become larger and more complex so too do the associated problems of installation, operation, maintenance, testing, and emergency operation. Networked systems have the potential to meet these new demands but the systems need to be flexible and adaptable enough to fully cover all spaces with minimal installation and be robust enough to detect problems and continue working even when sensors fail or are added, removed, or reconfigured. 
     SUMMARY OF THE INVENTION 
     The present invention uses stateless sensors and anonymous communication to create a more robust and functional lighting control system that is easier to configure, supports an unlimited number of sensors, allows sensors to added or removed, and supports remote operation, testing, and management. 
     Where known prior art systems use multiple, state-based, independent sensors the present invention introduces an improved Master-Scout event reporting concept wherein multiple Scout sensors send anonymous, stateless, event reports to a single Master zone controller. When an occupancy event is detected, Scout sensors report only that event. Each trip, regardless of source, has the potential to initiate or sustain the occupied state of the Master controller. As a zone becomes unoccupied, trip reports stop being sent allowing the Master control to time out and return to its idle state. Loss or addition of sensors does not affect operation because the Master does not need to know of or track individual sensors. Additionally, without the need to track individual sensors system functionality is greatly increased. The present invention allows trip reports to be created and sent by plurality of sources—not just other occupancy sensors—including momentary contact buttons, user controls, personal computers, and other building automation systems to include fire alarm, security, and access control. 
     Vacancy Logic 
     Vacancy logic with manual-on and auto-off load control has many advantages. Besides being more energy efficient, it is also inherently more reliable and intuitive for most applications. Because control systems cannot read minds, determining a user&#39;s actual intent is not possible. The best we can do is to use a proxy like motion or sound that detects physical behavior. However, with vacancy logic there is no uncertainty. If a user wants the lights or other loads on then they manually turn them on. Released from their conventional auto-on function, occupancy sensors no longer need to cover all entrances into a zone. This allows sensors to be specified and located to optimize coverage of high value areas like desks or the center of a conference room. However, there is a problem. If a user turns on lights without subsequently tripping the occupancy sensor the auto-off sequence is not initiated and the lights will not turn off. The present invention solves this problem by allowing the wall control to not only turn on lights but also send a trip report to the Master to initiate the auto-off sequence; whereby, lights will always turn off even if the occupancy sensor itself is not physically tripped. 
     Group Addressing 
     Another feature of the present invention is multiple group addressing. In addition to each zone having a unique zone or group address the present invention allows each Master zone controller to respond to broadcast commands and additional group commands. This capacity means that groups of Master controls can be created to cover not only a single room but also other larger control zones to include work areas, building floors, whole buildings, and even whole campuses. Applications include testing and system-wide response to emergency operation. 
     Testing and Documentation 
     In large and even smaller buildings testing and ongoing maintenance of systems can be difficult and expensive. Individual sensors can be locally tripped of course but even if the basic cost of getting to a room is ignored some rooms may be inaccessible and systematic field testing and documentation are inherently problematic. The present invention resolves this problem by providing the capacity to trip individual and groups of sensors remotely. Coupled with the ability of some networked lighting control systems to monitor the status of lighting objects, the system can be tripped and then queried to verify response. After a designated timeout, the system can again be queried to verify the expected response. With appropriate software the results of this type of test can also be captured to produce initial and ongoing system performance verification and documentation. 
     Interface to Other Systems 
     Emergency response is another critical function. Many known prior art systems do have the ability to turn lights on and off in response to emergency events but this can be intrusive as it can be difficult to know when to turn lights off after the emergency event is over. The present invention resolves this problem by allowing an emergency event to trip the Master zone controllers. If occupancy logic is being used the lights will turn on. If vacancy logic is being used tripping and turning the lights on can happen concurrently. In both cases the auto-off cycle will be initiated allowing unoccupied zones to respond to local conditions so that occupied zones stay on and unoccupied zones turn off. This capacity improves overall performance by assuring the required emergency response while reducing energy use and providing more intuitive operation. 
     DALI Auto-On Function 
     As part of its initial and emergency response operation, the DALI protocol requires that DALI ballasts turn on each time lighting power is cycled. In the event of a power outage longer than about 500 ms all DALI controlled lights will turn on. This can be a problem if the power cycle event happens late at night or at another time when the building is otherwise unoccupied. The present invention resolves this problem by providing an optional function that trips Master zone controllers to begin the auto-off sequence each time the DALI control power is cycled. If a particular room is occupied the lights stay on, otherwise, the zone times out and turns off. 
     Switch Timers 
     Delay-off switches are another embodiment of the present invention. In some areas the use of occupancy sensors may not be possible or economically justified. A typical application is unfinished space. Building codes typically require lighting and some form of auto-off control but placing occupancy sensors throughout the space may be unwarranted. In these and similar cases a delay timer can be used. Known prior art systems can support this kind of function with a simple twist timer but coordinating this function in rooms with multiple entrances can be problematic. Central relay panels can also be used but in addition to the cost of relay panels and home-run wiring this application typically requires occupancy sensors. 
     The present invention resolves this problem by allowing networked switches at each entrance to act as occupancy sensors. One switch is configured for Master control and occupancy logic while the others are set up as Scouts. When an on-button is pressed, a trip message is sent to the Master controller to turn lights on and initiate the auto-off sequence. Pressing any on-button in the space acts like a normal occupancy sensor and resets the occupancy delay timer to sustain the occupied, lights-on state. When the space becomes unoccupied the delay timer times out and turns off the lights. This approach has the additional advantage of being able to link the space into the lighting control system to provide a standard full function occupancy interface that includes adjustable occupancy delay time, remote control and monitoring, and a warning period that blinks or dims the lights before turning off. 
     Multiple Sensor Technologies 
     Occupancy detection with multiple sensor technologies is another application of the present invention. Multi technology occupancy detection is well established in prior art applications but in addition to the same problems of onymous communication and state tracking described above multiple technology sensors have an additional problem that occurs when sensor outputs must be treated differently. The problem occurs when different sensor technologies are used to cover a space. Prior art wired systems are able to side step the problem by resolving all sensor inputs to a single state change and switch closure. However, some sensor combinations like PIR and audio range acoustic may require that sensor events be treated differently. The present invention allows for this by enhancing its communication protocol to include multiple message types that identify sensor trips by their technology type. With this additional information the Master zone controller can then process each type of sensor trip separately in order to provide complete multi-sensor, multi technology benefits. 
     Other features and advantages of the present invention will become apparent from the following description of the invention that references the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified system deployment overview of a lighting control system with a variety of actors and actor surrogates having input into the system where actors are actual persons and actor surrogates are items like sensors and scheduling means that operate on the system through algorithms that embody actor intensions. 
         FIG. 2  is a simplified static diagram of zone control showing the interaction of objects within the system. 
         FIG. 3  is a simplified state diagram of a button control object. 
         FIG. 4  is the state diagram of a Scout control object. 
         FIG. 5  is the state diagram of a Master control object. 
         FIG. 6  is a simplified deployment diagram of a switch timer embodiment. 
         FIG. 7  is a Switch Timer Static Model. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The foregoing summary, as well as the following detailed description of the preferred embodiments, is better understood when read in conjunction with the appended drawings. For the purposes of illustrating the invention, there is shown in the drawings an embodiment that is presently preferred, in which like numerals represent similar parts through the several views of the drawings, it being understood, however, that the invention is not limited to the specific methods and embodiments disclosed. 
       FIG. 1  is a simplified system deployment diagram of the preferred embodiment of the present invention showing the primary physical components. All of these components are linked together via a common communication network which is a combination of a fast Ethernet backbone network  124  and a plurality of smaller, slower local DALI networks  126  connected through a plurality of network gateways  128 . Each of these components are called network nodes or just nodes and have the capacity to communicate with the network and to store and run computer instructions. Computer instructions that run on these nodes are bundled together into discrete firmware packages called objects. Each object is an instance of a set of computer instructions called a class and each object is made unique by property settings and a unique identification. 
     Master and Scout devices  110  and  112  are both nodes and sensor platforms. They may be physically identical but configured to operate differently. Scouts have an activated Scout object  218  and perform the job of detecting and reporting occupancy events to the Master object  220  via the DALI network  126 . User controls  116  are nodes that connect to the DALI network  126  and have the capacity to host objects including buttons  216 , Scout  218 , and Master  220  objects. DALI loads  114  are nodes that host DALI load control objects and have means of regulating an electrical load. Examples of DALI loads include dimming ballasts, incandescent dimmers, DALI to 0-10 v gateways, and digital outputs connected to relays. These devices may be stand alone or included with other nodes such as the preferred embodiment where all Scouts and Master nodes include a digital output that can drive a self-powered relay or communicate with other devices and systems. Occupant workstations  120 , laptops  118 , and a system controller/server  122  can also host control objects and communicate with Scout  218 , Master  220 , and button  216  objects via the network. 
       FIG. 2  is a simplified static diagram of a single zone that shows the relationship between the control objects. A typical zone is identified by a unique zone address and has one Master control object  220  and a plurality of support objects consisting of buttons  216 , Scouts  218 , and loads  214 . Additionally, there may be any number of external objects and support programs  212  that can also provide control messages. Masters objects  220  process both local and remote sensor input in order to determine the occupied status or state of a zone and use this information to regulate electrical loads via instructions to the DALI load objects  214 . 
     Objects interact to determine the occupied state of a zone and regulate the zone load by sending and receiving messages to or from the zone address eliminating the need to identify and track individual addresses. These messages are labeled M 1  through M 6  and support two sensor types. A first sensor type of the preferred embodiment is a PIR (Passive Infrared) sensor that detects motion by monitoring changes in infrared energy. A second sensor type is a PAR (Passive Audio Range) sensor that detects occupancy by listening for non-periodic sound. When a Scout detects an event it informs the Master by sending an M 1  report for a PIR event and an M 2  report for a PAR event. 
     The job of the M 1  and M 2  reports is to inform the Master control object that an occupancy event has occurred. These events may have been created by actual sensors or alternatively by some other action like a button press. Regardless of actual source, the Master control object treats all M 1  and M 2  reports the same without regard to origin or state allowing the reports to be both anonymous and stateless. 
     A third message type M 3  may be sent to the load control objects. In the preferred embodiment this message format conforms to the open source DALI protocol and may be any command that instructs the DALI load control object to regulate an electrical load. On-commands include goto-level, goto-scene, goto-minimum, and goto-maximum all of which regulate loads via various actuators including relays, dimming ballasts while off-commands include off, off with fade, and step down and off. Within this specification these command groups are called DALIon or DALIoff commands and may be generated by a variety of sources including user interface objects  216 , Master controller objects  220 , and other objects  212 . 
     A fourth and fifth message type, M 4  and M 5 , are also supported. Like M 1  and M 2 , these messages are also commands which are anonymous and stateless and are tagged as being created by a first or second sensor type. These commands are only processed by Scout sensors in order to simulate a Scout trip which in-turn generates an M 1  or M 2  trip report that is sent to the zone Master controller. In this way Scout sensors can be remotely tripped while the monitoring the Master controller in order to verify that the Scouts are configured and operating properly. 
     A sixth message type, M 6 , is additionally supported which operates like M 4  and M 5  commands but simulates the physical act of pressing a button. This command may be used to test the configuration and operation of user interfaces as well as allowing user interface buttons to be remotely operated to provide expanded user and automatic control. 
       FIG. 3  is a simplified state diagram of a button control object  216  configured for the preferred embodiment of vacancy logic. The button has one state, idle  314 . When the button is pressed it creates an event  312  and a set of actions  216 . The first action is to send an M 3  message to Load object  214  to turn lights on. The second action  216  is to send an M 1  or M 2  message to the Master control object  220  to initiate the auto-off sequence. 
       FIG. 4  is a simplified state diagram of the Scout control object  218  configured for the preferred embodiment of two sensor technologies  414  and  416  and a transmit delay timer  412 . In this embodiment the first sensor technology is a Passive Infrared (PIR) motion sensor and the second is a Passive Audio Range (PAR) acoustic sensor. PIR sensors have excellent line-of-sight characteristic but cannot “see” through barriers. PAR sensors detect sharp changes in audio-range sound that allows them to “hear” both directly and around barriers. The two technologies complement each other to provide a level of detection superior to what either can do by itself however the two sensor types must also be processed differently to assure optimal performance. The embodiment also incorporates logic to reduce network traffic by introducing a delay between trip reports and logic to assure that PIR trips are always reported even if the Scout has been previously tripped by the PAR sensor. 
     The state diagram begins with the sensor in its idle state  410 . When either sensor trips or an M 4  or M 5  trip report is received, the Scout object changes from said idle state  410  to the transmit delay state (XD)  412 . If the trip is from a PIR sensor or M 4  trip command then an M 1  trip report is sent followed by a second action to set the PIR trip flag  414 . If the trip is from a PAR sensor or a M 5  trip command then an M 2  trip report is sent  416 . Either type of trip starts the transmit delay timer (XDT)  418  before entering the transmit delay state  412 . However, if the trip came from a PAR sensor  416  the Scout will still respond to a PIR sensor trip, send an M 2  trip report, and set the PIR trip flag  420 . When the XDT times out  422  or a DALIoff command addressed to the designated control zone or parent zones thereof is detected  424 , the Scout object  218  clears the XDT and returns to its idle state  410  wherein the PIR trip flag cleared so that the Scout is ready to process another trip event. 
       FIG. 5  is a simplified state diagram of the Master control object  220  configured for the preferred embodiment of vacancy logic and first and second PIR and PAR sensors. The embodiment demonstrates the advantage of being able to process the two sensor technologies differently. PAR sensors are more susceptible to false tripping so the Master typically only allows a PIT trip to initiate a change from the idle state  510  to occupied state  514 . However, once in the occupied state  514 , acoustic trips are accepted but only for a limited time which is reset each time a PIR trip is detected  530  and  528 B. 
     The state diagram begins with the Master object  220  in its idle state  510 . When the PIR sensor trips or an M 1  message is received  516 , the object  220  moves from its idle state  510  to its occupied state  514  while setting the AOT (Acoustic Override Timer)  520 . Upon entry into the occupied state  514  the OST (Occupied State Timer) is set. While in the occupied state  514 , a trip of either a PIR  522  or PAR sensor  530  or the receipt of either an M 1  or M 2  reports from a Scout or other source resets the OST to sustain the occupied state  514 . However, the two sensors and their associated M 1  and M 2  reports are not treated the same. A PIR sensor trip has the additional job of setting the AOT  520  while a PAR sensor trip  522  only resets the OST  514 . 
     The occupied state is sustained until the either the OST  524  or the AOT  534  times out or a DALIoff command addressed to the designated zone or parent zones thereof is detected  538 . In the preferred embodiment both the OST  524  and AOT  524  timeout events move the object  220  to a warning state  512 . However an AOT event  534  also disables any further PAR trips  534 . Upon entry into the warning state  512  a sequence of actions occurs. First, commands are sent to the DALI load control objects in the designated control zone  214  to capture their current light level to their scene 15 then to dim or turn off depending on their load type, followed by a final internal command to set the WST (Warning State Timer) to its timeout value. 
     The warning state is sustained until a recognizable sensor trip event  528  occurs, the WST times out  536 , or a DALIoff command addressed to the designated control zone or parent zones thereof is detected  538  is detected. recognizable sensor trip or trip command  528  causes the object  220  to return to its occupied state  514  after first sending a DALI command to DALI load control objects in the designated control zone to return to their scene 15 value  528 . If the trip originates from the PIR sensor or M 1  trip report  518  then the AOT  520  is also set. If a trip event is not detected or said DALIoff command is detected the Master object returns to its idle state  510 . Entry into the idle state clears all timers and flags whereupon said object  220  is ready to respond to another trip event. 
     Master controllers configured for automatic-on operate the same way except for incorporating an action to send a DALIon command to DALI load control objects in the designated control zone  214  during the idle to occupied state transition  516 . 
       FIG. 6  is a simplified deployment diagram of a three station  116  switch timer system wherein a single electrical load is regulated by a relay  614 . In this embodiment there are no occupancy sensors. Rather, users entering a space manually turn on the lights from any one of the three stations by pressing an on-button. Lights are turned off by manually pressing the off button at any user control or after a timeout period has passed. 
     The three stations  116 A,  116 B,  116 C are all connected to a DALI network  126  and each station is configured with two buttons, one for on and one for off. In addition to user buttons one of the stations also hosts a Master control object  220 . Except for the physical difference of not having occupancy sensors, the embodiment operates the same and uses the same Master Control Object logic detailed in  FIG. 5 . This is a significant advantage over prior art system as it allows this special application to be configured, operated, and maintained using the same user interfaces, concepts, and equipment as systems that have occupancy sensors. 
     Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.