Digital Addressable Lighting Interface - School of Engineering

1 Digital Addressable Lighting Interface Robert David Brinzer (0908809b) Supervisor: Scott Roy Conventional versus Digital Lighting Circuits Light circuits have traditionally been among the most simple electrical circuits one can make. Lights Switch are placed in series with a switch. The switch can then be used to turn the lights off by breaking the Controller on circuit. This only allows for a few basic circuit topologies which are not very flexible. By introducing Digital control circuitry into lights they can be made to perform more complicated tasks such as dimming or checking their status. Each light communicates with a Lighting controller which can control large numbers of lights individually. This provides several advantages. Switch off Cheaper installation, less money spent on mains rated cables to reach switches.

2 Easier maintenance, lamp faults can be reported back to controllers as they happen. Conventional Lighting Improved energy efficiency, controllers can be made to optimize light power usage. Digital Lighting More convenience, all lights can be controlled from a single controller, possibly remotely. Digital Addressable Lighting Interface Standard Making Software for a DALI Control Gear To facilitate Digital control of Lighting circuits a standard was Control gear behavior translates well to a software stack defined by the British Standards Institute[1] called the Digital implementation on a microprocessor. The communication layers Addressable Lighting Interface (DALI). This networks lights were implemented in C++ onto a mbed[2] LPC1768. together using a custom communication protocol and bus network topology.

3 Communication is done through wires which Persistent Light Sensors Network run either inside specially designed power cables or as separate Storage Driver cables to reach a controller. Each light is managed by a uniquely Addressable control gear that processes and responds to commands sent on the network. Control Logic Controller Control Gear Interrupt Space Communication is done in frames using Manchester coded bits at approximately 1,000 baud. Communication Send Receive 1 1 1 1 0 0 0 0 Manchester Manchester I/O. Shape of a backward frame signal. Although such networks are limited in size to 64 separate lights, DALI Software Stack. this is more than sufficient for household purposes and in commercial premises multiple controllers can be used. The Manchester layer is responsible for sending and receiving frames through the communication bus.

4 The communication layer is responsible for framing data and sharing the bus. The Bathroom(s). Kitchen control gear control logic must outsource to other components Living room that are unrelated to the stack. The requirements of the controller logic are derived from the system use cases. Bedroom(s) Outside In order to allow the microprocessor to operate efficiently both Controller Manchester and communication layers are implemented using interrupt driven state machines. This gives the combined stack Possible DALI uses at home. many advantages over known existing implementations. Controllers can be designed around activities such as No polling is used greatly improving multitasking. communicating with a smartphone app for remote Lighting Duplicate control gear logic can manage any number of lights control, using motion sensors to conserve power or even through same communication layer with no added overhead.

5 Adjusting lights automatically based on time of day or weather. A single microprocessor can efficiently act as a controller for many DALI networks communicating in parallel. The software stack can be easily maintained and ported to different microprocessors. Designed to be open source so anyone can use it. LPC1768. communicating with The resulting controller stack successfully communicated with a fluorescent light commercially available DALI light as well as with itself. [1] Digital Addressable Lighting Interface [2] mbed Development Platform for University of Glasgow, charity number SC004401 Part 102: General requirements Control gear, Devices, (2014). British Standards Institute, BS EN 62386-102:2009.