Electric lamp and discharge devices: systems – Current and/or voltage regulation – Plural load device regulation
Reexamination Certificate
2000-11-15
2003-01-14
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Current and/or voltage regulation
Plural load device regulation
C315S292000
Reexamination Certificate
active
06507158
ABSTRACT:
TECHNICAL FIELD
This invention relates to an enhancement of the DALI protocol, additionally enabling the manual control of digital ballasts in a lighting control network, and a DALI compliant communications apparatus to interpret the enhanced protocol. The invention has particular application in a lighting control network compliant with the Digital Addressable Lighting Interface (DALI) standard.
BACKGROUND OF THE INVENTION
DALI—the Digital Addressable Lighting Interface
The DALI protocol is a method whereby electronic ballasts, controllers and sensors belonging to the system in a lighting network are controlled via digital signals. Each system component has its own device-specific address, and this makes it possible to implement individual device control from a central computer.
History of the DALI Protocol
Research work connected to the DALI project began midway through the 1990s. However, the development of commercial applications got underway a little later, in the summer of 1998. At that time, DALI went under the name DBI (Digital Ballast Interface). An interface device (or ballast) is an electronic inductor enabling control of fluorescent lamps. The DALI standard has been the subject of R&D by numerous European ballast manufacturers such as Helvar, Hüco, Philips, Osram, Tridonic, Trilux and Vossloh-Schwabe. The DALI standard is understood to have been added to the European electronic ballast standard “EN60929 Annex E”, and was first described in a draft amendment to International Electrotechnical Commission 929 (“IEC929”) entitled “Control by Digital Signals.” DALI is thus well known to those skilled in the art. Due to this standardization, different manufacturers' products can be interconnected provided that the manufacturers adhere to the DALI standard. The standard embodies individual ballast addressability, i.e. ballasts can be controlled individually when necessary. To date, ballasts connected to an analog 1-10 V DC low-voltage control bus have been subject to simultaneous control. Another advantage enabled by the DALI standard is the communication of the status of ballasts back to the lighting network's central control unit. This is especially useful in extensive installations where the light fixtures are widely distributed. The execution of commands compliant with the DALI standard and obtaining the status data presupposes intelligence on part of the ballast. This is generally provided by mounting a microprocessor within a DALI compliant ballast; the microprocessor also carries out other control tasks. Alternatively, two microprocessors can be utilized; one to interpret and service the DALI communications, and the other to provide the lamp control and diagnostics. The first products based upon the DALI technology became commercially available at the end of 1999.
Digital Control
The word ‘digital’ is a term which has become familiar to us all in the course of this decade in connection with the control technology built into domestic appliances as well as into industrial processes. Now, digital control is becoming increasingly common in the lighting industry as a result of the new DALI standard.
DALI Message Structure
DALI messages comply with the Bi-Phase, or Manchester, coding scheme, in which the bit values ‘1’ and ‘0’ are each presented as two different voltage levels so that the change-over from the logic level ‘LOW’ to ‘HIGH’ (i.e., a rising pulse) corresponds to bit value ‘1’, and the change-over from the logic level ‘HIGH’ to ‘LOW’ (i.e., a falling pulse) corresponds to the bit value ‘0’. The coding scheme includes error detection and enables power supply to the control units even when there are no messages being transmitted or when the same bit value is repeated several times in succession. The bus's forward frame (used in communications from the central control unit to the local ballast) is comprised of 1 START bit, 8 address bits, 8 data/command bits, and 2 STOP bits, for a total of 19 bits. The backward frame (from the local ballast back to the central control unit) is comprised of 1 START bit, 8 data bits and 2 STOP bits, for a total of 11 bits. The specified baud rate is 2400.
DALI messages consist of an address part and a command part. The address part determines which DALI module the message is intended for. All the modules execute commands with ‘broadcast’ addresses. Sixty-four unique addresses are available plus sixteen group addresses. A particular module can belong to more than one group at one time.
The light level is defined in DALI messages using an 8-bit number, resulting in 128 total lighting levels. The value ‘0’ (zero), i.e., binary 0000 0000, means that the lamp is not lit. The remaining 127 levels correspond to the various dimming levels available. The DALI standard determines the light levels so that they comply with the logarithmic regulation curve in which case the human eye observes that the light changes in a linear fashion. All DALI ballasts and controllers adhere to the same logarithmic curve irrespective of their absolute minimum level. The DALI standard determines the light levels over a range of 0.1% to 100%. Level 1 in the DALI standard, i.e., binary 0000 0001, corresponds to a light level of 0.1%.
Typical DALI Messages
Go to light level xx.
Go to minimum level.
Set value xx as regulation speed.
Go to level compliant with situation xx.
Turn lamp off.
Query: What light level are you on?
Query: What is your status?
From Analog To Digital
The idea concerning the DALI protocol emerged when the leading manufacturers of ballasts for fluorescent lamps collaborated in the development of a protocol with the leading principle of bringing the advantages of digital control to be within the reach of as many users as possible. Furthermore, the purpose was to support the idea of ‘open architecture’ so that any manufacturer's devices could be interconnected in a system.
In addition to control, the digital protocol enables feedback information to be obtained from the lighting fixture as to its adjustment level and the condition of the lamp and its ballast.
Examples of typical applications for systems using the DALI protocol are office and conference facilities, classrooms and facilities requiring flexibility in lighting adjustment. The lighting-control segment based on the DALI technology consists of maximum 64 individual addresses which are interconnected by a paired cable. DALI technology enables cost-effective implementation of lighting control of both smart individual lighting fixtures as well as of numerous segments connected to the automation bus of a building.
Because the DALI standard assumes that the local electronic ballast will be continually under the control of the central computer controlling the network or the series of networks (recall that under the DALI standard
64
unique addresses are available, but by setting one or more of these unique addresses to be assigned to another network chaining of networks can result and numerous individual luminaries can be controlled) there is no facility in DALI for temporarily taking a particular ballast “off line” and subjecting it to purely manual control, and then setting it back “on line.” As a result, under the current state of the art, in order to allow for the manual control of a local electronic ballast by the occupant of the room or office in which that ballast exists, some additional circuitry or wiring would be required to somehow cause the manual suspension of commands coming from the lighting network for an interval of time. Such additional circuitry or wiring would be in addition to the existing circuitry in the electronic ballast increasing the cost of the ballast and its complexity. Alternatively, additional circuitry and wiring could be provided to control the ballast by DC control or by a pulse width modulation, but this option would also increase the cost and complexity. What is desired is a protocol which would enhance the DALI standard, and would be easily decodable by DALI compliant ballasts without the addition of additional circuitry or
Koninkljke Philips Electronics N.V.
Lee Wilson
Wong Don
LandOfFree
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