What is D4i and how does it impact a DALI installation
D4i is an extension of the DALI standard that looks enable luminaire level lighting control with enhanced data and diagnostics. One of the biggest changes included within D4i is the supply of an in-built DALI power supply within the luminaire driver directly, essentially taking care of the power requirements of the DALI line that it is connected to.
D4i DALI Power Supply:
DALI Part 250 - Integrated Bus Power Supply - Mandatory
This power supply (approximately 50-60mA in size) is designed to power a small DALI line that is then wirelessly connected back to a wireless DALI application controller. These DALI "sub-lines" then mesh together to form a full DALI line capable of communicating with each other without the physical DALI wire linking between them.
Due to the nature of a D4i device being backwards compatible with DALI, this means that a D4i driver can be used as apart of a new or existing DALI line. This poses a significant risk whereby 1 or more D4i drivers could be delivering power to a DALI line, potentially exceeding the 250mA maximum allowed. It is advised to confirm as apart of any DALI installation whether or not the luminaires include a D4i driver, and if the in-built power supply has been turned on.
Note: According to DALI part 251, the default status of the DALI power supply found in a D4i driver is left up to the driver manufacturer.
In most cases, there are two ways to enable/disable the DALI power supply found in a D4i driver.
- A D4i driver often includes the ability to commission basic parameters of the device via NFC (Near Field Communications). This includes the ability to enable/disable the power supply. This method is determined by the manufacturer of the D4i driver, and is not brand agnostic.
- Via a DALI programming tool with support for DALI Part 251 - Luminaire Data
Examples:
- A Philips D4i driver can be programmed via an Android device which support NFC via the MultiOne app. Opening the app and scanning the NFC tag on the D4i driver will provide you with the properties of the device, including the ability to enable/disable the DALI power supply. This is then saved back to the Philips driver.
- Any D4i driver connected to a zencontrol application controller can have its power supply enabled/disabled via Grid View -> Device Types -> Integrated PSU. This forces the D4i driver to configure the state of the power supply via DALI.
Note: If there is a D4i driver on a DALI line where it is otherwise powered via a standalone DALI power supply, there is the potential that a DALI line could be exceeding the 250mA maximum current allowed, remove power from the line and consult with the manufacturer of the D4i drivers for further advice. Situations can arise where damage to DALI devices connected to the line can occur.
If we consider the example of a DALI line which consists of 20 D4i drivers, and these drivers can supply 50mA of DALI power, this could mean that the DALI line is supplying 1A of DALI power, in effect causing the line to exceed the 250mA maximum 4 times over. Since the best recommendation here is to shut the DALI line down, this means that configuring the D4i DALI power supplies via DALI is not an option until the DALI line is below 250mA again.
This means that either the DALI line needs to be physically segregated temporarily, bringing the power supplied to the line below 250mA (approximately 5 D4i drivers), and disabling the power supplies via a suitable DALI tool, repeating this process until the line is confirmed to be without excessive DALI power OR to use the D4i driver's manufacturers tools to commission the driver directly.
D4i Enhanced Data Capabilities:
As apart of the D4i standard, additional properties about the driver can be collected and used as apart of the lighting control system so long as it is a supported property by the lighting control system.
Built as apart of a D4i driver are the following capabilities:
- DALI Part 251 - Luminaire Data - Mandatory
- luminaire supply power & voltage
- light output,
- CCT & CRI,
- light distribution
- luminaire colour, and more.
- DALI Part 252 - Energy Data - Mandatory
- Active energy/power
- Apparent energy/power
- Load-side energy/power
- DALI Part 253 - Diagnostic Data - Mandatory
- Failure conditions for control gear and lamps, including counters.
- Control gear information: Operating time, start counter, supply voltage and frequency, power factor, temperature and output current.
- Light source information: Operating voltage, current, temperature, light source start counter, light source on time.
D4i offers an enhanced range of additional features beyond what DALI-2 is directly capable of, and provides more information back to the installer as well as the building owner. Its primary purpose is to provide additional knowledge to be used as part of greater decision making within a building, it is also a forward step towards an IoT native solution.