29-12-2010, 02:45 PM
By
MAYANK BHARADWAJ,SAURABH SINGH & GAURAV GUPTA
MAYANK BHARADWAJ,SAURABH SINGH & GAURAV GUPTA
PROJECT SYNOPSIS WITH Eng.doc (Size: 1.85 MB / Downloads: 94)
INTRODUCTION
The demands on modern lighting technology are numerous. In former times there was but one objective, to provide light for visual tasks. Nowadays convenience, functionality and energy conservation are attractive features, which must be added as objectives. The traditional electric installation that is based on the simple wiring of light switches, dimmers and light consumers is inadequate of responding to these demands. Controls with analog interfaces, like the 1-10V control, neither provide the flexibility nor the capability of controlling individual lights in a system. This makes the extension of an existing system a rather difficult task. This is why installation bus systems have been developed since the 1980’s allowing a digital communication between all participating components of a lighting system or even in the engineering of Building Systems. High functionality and flexibility of the technical unit is ensured in these systems, where commands are exchanged between control devices and electric consumers.
These installation bus systems, which are already established on the market, regularly entail a high expenditure for devices and systems. They also demand extensive system knowledge from both the designer and electrician that has to be acquired in special training sessions. Consequently the installation of such systems is labour-intensive and expensive.
This experience has laid the ground for the lighting industry to define a new standard for the digital communication between the individual components of a lighting system: the
DALI-protocol (DALI = Digital Addressable Lighting Interface).The objective was to create a system with low cost components that is easy to handle. This system intentionally dispenses with the maximum possible functionality in the engineering of complex Building Systems in favour of simplified communication structures. An optimized set of commands is established, which are limited to the sensible functions of a lighting control. It is possible to integrate DALI as a subsystem into superior Building System designs, if so desired, taking advantage of the available hardware and software interfaces and this at favourable prices.
DALI – the digital addressable lighting Interface
The analog 1 – 10V control interface is the most common industry standard for the dimming of electronic ballasts today. DALI has been designed to become a new standard in the market. With its greater flexibility and simplicity of installation in a great variety of applications it will gradually replace the analog interface.
WHAT IS DALI?
DALI is an acronym and stands for “Digital Addressable Lighting Interface“. It is an international standard that guarantees the exchangeability of dimmable ballasts from different
manufacturers. This gives planners, luminaire manufacturers, building owners, installers and end-users the security of supply from many sources.
DALI is the ideal, simplified, digital way of communication tailored to the needs of present day lighting technology.
Communication and installation have been simplified as much as possible. All intelligent components communicate in a local system in a way that is both simple and free of interference.
There are no special requirements for the wiring of data cables, and there is no need to install termination resistors on the cables to protect them against reflections.
DALI has been designed in a joint effort by all leading control equipment manufacturers with the idea of offering a standard to the lighting market that complies with all requirements.
All lighting component manufacturers are now in a position to solve complex lighting tasks in a simple and comfortable way.
With this standard you will now be able to offer your customer a full system solution (lamp – ballast – luminaire – control unit – lighting system).
BACKGROUND
The building automation application segment is changing rapidly. Up to now words like energy- saving and power management were acronyms of complexity, expensive architecture and products difficult to find. Thanks to the lower price of electronic components, the market demand on these segments is growing. Leading manufacturers attempted to gain this business designing their own systems developing many kinds of proprietary solutions. As a result of this approach, the integration capability and information exchange among other subsystems has not been possible or was again costly. Then the main manufacturers formed technical committees to define a common standard platform to be used in fully integrated building automation systems.
Independently by the architecture that will be used, the basic common features are: easy to use human interface, energy saving management, modularity and integration capability. The aim of this project is to show how to implement a cost effective communication system and a smart lamp control in order to increase the system efficiency, the tube life cycle, the human comfort and reduce the power consumption. Those objectives can be combined by using both the DALI system architecture and an 8-bit low cost microcontroller embedding a dedicated module and flexible low power consumption modes.
ORGANISATION OF WORK
DALI-AG organisation
STMICROELECTRONICS
Under the roof of the German Central Association of the Industry for Electric and Electronic Products (registered committee: ZVEI)
PROBLEM DEFINITION
PROJECT OBJECTIVE
Modern offices and building management are requiring efficient but cost effective lighting control systems. Energy saving requirements and comfort are calling for dimmable fluorescent lamps controlled by daylight sensors and control for individual workplaces. In order to have a centralized control of each dimmable ballast of a room, a communication protocol is needed. Therefore it is desire to implement DALI (Digital Addressable Lighting Interface). Since DALI is a digital protocol, a microcontroller is needed.
In this project various topologies will be presented to integrate this digital communication.
Starting from the basic analog topology, the microcontroller can work together with an analog ballast controller, just for DALI communication in this case, we design to create DALI ballast. This solution is explained in detail in section “Implementation with DALI Microcontroller + Analog Half Bridge Controller”. But the microcontroller functions can be extended. It can do the DALI communication and by digital control take the place of the analogue ballast control. In this case, the designer will have to do a complete redesign of his control section. The benefit is flexibility, since the system parameters can be set by software and no more by external components. . This solution is explained in detail in section “Implementation with DALI Microcontroller + Half-Bridge Level shift driver”.
A new microcontroller has been developed to decode the DALI protocol and support whichever solution is chosen. An estimation of the energy saving using a DALI ballast system is given.