Patent Application
20080316743
This invention relates to lighting systems for activity areas such as athletic fields for baseball, football, soccer, and the like and more particularly to a lighting system which provides selectable multiple levels of lighting intensity as well as automatic, adjustment of individual fixture lighting intensity to achieve substantially uniform lighting from all fixtures in an array or grouping of fixtures as well as between all of the fixtures in a multiple, array system.
It is well known to use high intensity lighting fixtures using metal halide lamps and parabolic reflectors to illuminate activity areas such as athletic fields used for baseball, football, soccer, tennis, go-cart racing and other sports activities. The typical installation comprises clusters or groupings of fixtures mounted on cross-arms which are typically mounted on poles surrounding the athletic field to direct high intensity lighting onto the activity area.
The typical system is turned on at a master control location. The system, may be turned off manually or by timers which cut power to the system after a pre-selected amount of operating time or at a particular time of day. Controls can also be provided to permit the energization of fewer than all of the available fixtures where full intensity lighting is not needed.
It is well known that there are small differences between individual fixtures using new lamps and even greater differences between individual fixtures as the lamps age. If lamps are replaced on an individual basis rather than in groups in a large multi-fixture system, the result can be a system with conspicuous differences in the intensity and color of light from the fixtures.
It is also well known that high-intensity arc-type lighting fixtures require the use of ballasts to control current after the arc is established; i.e., to introduce resistance into the lamp circuit as it transforms quickly from the high-resistance, pre-arcing state to the low-resistance arcing state. Ballasts can take many forms, the most, pertinent of which are the so-called electronic ballasts as described in U.S. Pat. Nos. 7,109,668; 7,139,680; 6,914,395; 6,879,113; 6,541,923; 6,351,081; 6,107,754; 5,550,437; 5,434,478 and 4,441,053 as well as pending application Publication Nos. 2006-0197470 and 2005-0179404.
In accordance with the present invention, precise intensity control of individual fixtures as well as a high level of uniformity between all fixtures in an array is achieved. The present invention provides not only an overall intensity command capability which permits the selection of one out of several available overall intensity levels for all of the fixtures in an array, but further provides a feedback style-arrangement, for adjusting the output, levels of individual fixtures in small increments via electronic and other switchable ballasts including capacitive ballasts and resistive ballasts so that ideally all of the fixtures in an array of in multiple arrays produce essentially the same light intensity and color at any given time.
In the preferred embodiment of the invention, a local command center is provided at the activity area where, if desired, an operator can provide inputs through switches or a keyboard or other types of data entry instrumentalities, to select a normal overall lighting intensity level for all the fixtures aimed, at the lighted play area. The selected overall intensity level from the local command center is communicated to logic systems mounted close to the fixtures; e.g. on the supports (poles) for the individual clusters, and from this point, intensity commands are delivered to multi-level intensity control units, hereinafter termed “dimmer packs”, which preferably contain electronic ballasts capable of adjusting the intensity level of one or more individual fixtures in small increments between larger nominally selected increments in accordance with signals received from photosensors associated with each individual fixture. For example, if the light, outputs from two out of eight individual fixtures in a cluster are below the level selected for all eight fixtures, the sensors associated with those fixtures develop signals indicating the low output intensities, and these signals are used to adjust the intensity level upwardly in increments via the dimmer packs until all of the fixtures in the cluster are producing light at substantially the same intensity level.
The data transfer between the command center and the logic circuits associated with the dimmer packs can be hard wired but, in the preferred embodiment described herein, is accomplished by a short range RF link providing two-way data transfer. Within the logic itself is a feedback loop including the commanded or requested intensity signal and an actual intensity signal from the sensor. If the two match, there is zero error and no adjustment is made. If there is an error, an adjustment of the correct size and sense is made.
If, for example, the sensor signal indicates that a given lamp is effectively producing no light at all, that information, along with the fixture location identity, is sent back to the control center via the RF link.
Intensity commands can also come from a remote control, location by telephone line, RF, VHF, or cell phone to the field center. A system for the remote control of lighting is described in U.S. Pat. No. 6,922,679 for “Software Integration Method to Automate Lighting Control at Parks and Recreation Facilities,” the entire disclosure of which is incorporated herein by reference.
In a specific system, selectable intensity levels may be associated with “practice”, “league play”, and “tournament play”, each nominal level calling for a higher level of light intensity within the maximum capabilities of the overall system. Between each of the “practice”, “league”, and “tournament” play levels, there are numerous smaller increments of available intensity adjustments producible by the individual fixture dimmer packs so that the output intensity level of each individual fixture can be fine tuned toward overall, system uniformity. The names “practice”, “league” and “tournament” are illustrative rather than exhaustive.
The features and advantages of the invention will be best understood from a reading of the following specification which describes and illustrative embodiment in detail.
Referring now to
Each of the fixtures 16A and 16B has associated therewith a dimmer pack 22 which is designed to provide ballast and multi-level intensity control; i.e., to provide a large number of selectable increments of light output intensity as indicated by the small increment lines 60 shown in
As shown in
Each of the fixtures 16A and 16B is equipped with a photosensor 42, 44 which produces an output signal, representing the actual, light output intensity from its associated fixtures. Sensor 42 is connected by line 46 to the logic box 30 to provide a feedback signal representing the actual, performance of the fixture 16A. This signal is connected, to a comparator 48 which also receives the nominal output level signal from the set command unit 50 in the logic box 30. If there is a difference between the nominal commanded output level and the actual performance level, the comparator 48 produces an error signal on line 52 which is fed back to the unit 50 to adjust the output in line 52 which is fed back to the unit 50 to adjust the output on line 32 by one or more of the small increments 60 shown between the nominal levels in
In the event one of the lamps 20 burns out, the absence of a signal from the associated sensor 42 during a time when the fixture is expected to be on and producing light is interpreted by the logic box 30 as a burnt out or defective fixture and information regarding: the specific fixture with the burnt, out bulb is sent back to the command center 24 by way of the short range radio link 26, 28. This information can also be used to incrementally increase the light intensity from all of the remaining operational fixtures 16 in the cluster containing the burnt out lamp so that the level of light intensity on the field 10 remains at the desired level. This result is most easily achieved where the logic units 48, 50 are used for all of the fixtures in the cluster and the appearance of a burnt out bulb signal on any of the lines 46, 54 automatically triggers the incremental increase in the intensity level of the remaining operational fixtures.
The field command center 24 may be provided with a maintenance memory and/or a printing capability so as to make of record the fact that an individual fixture contains a burnt out lamp and schedule maintenance by way of the replacement of that lamp at a specific time. To achieve this, each dimmer pack must have its own code and this code must be sent back to the command center 24 along with an indication. A ten digit code similar to that used for garage door operators can be used. The system may also be used to monitor individual, lamp intensities and make a record thereof so as to schedule lamp replacement in an organized and systematic fashion. The field command center 24 is preferably equipped with a microprocessor capability which can readily be programmed to provide these and other accessory type features.
The short range radio link 26, 28 may be provided using UHF, VHF infrared and/or any of a number of alternative short range radio protocols approved by the Federal Communication Commission and capable of carrying the desired data/intelligence level. The “Bluetooth” data protocol has been found acceptable.
While the inventive subject matter disclosed herein has been described in connection with a specific and illustrative system, it is to be understood that not all features of the system need be used together and further that various modifications and additions may be made by designers of individual systems.
