Direct answer: Budget a DALI bus using the connected devices’ specified bus consumption and the bus power supply’s guaranteed current. Then separately check the maximum total current of every enabled bus supply against the applicable system limit. A sufficient number of addresses or a powerful LED power supply does not prove that the control bus has enough current.
What belongs in a DALI bus budget?
Ο DALI Alliance Quick Start Guide separates the bus supply from control gear, application controllers and input devices. Some products include an integrated bus supply; others draw from the bus. Record the exact role and the manufacturer’s values for every installed device, including controllers and sensors, not just drivers.
The same guide describes a nominally 16 V bus and a maximum supply current of 250 mA. Use the published limits for the actual installation and document versions. A separate LED power output supplies the light source; its power rating is not a DALI bus current rating. Neither an ordinary auxiliary DC supply nor the pictured 12 V HLG unit can be assumed to power or communicate on a DALI bus.
Worked example: calculate consumption and supply separately
The following values are invented for arithmetic practice, not specifications for WEHO or any DALI product. Assume one compatible bus supply has a guaranteed 100 mA available and a maximum output of 120 mA; all listed consumption values are worst-case values from a hypothetical common basis.
| Connected bus load | Quantity × assumed current | Budget |
|---|---|---|
| Control gear | 20 × 2 mA | 40 mA |
| Input devices | 4 × 6 mA | 24 mA |
| Application controller | 1 × 12 mA | 12 mA |
| Total consumption | 40 + 24 + 12 | 76 mA |
On those assumptions, the guaranteed-current margin is 100 − 76 = 24 mA. This is a screening result, not an installation approval: use the manufacturer’s actual current definitions and verify the full device list and wiring.
Now suppose an additional device has a separately enabled integrated supply with a maximum of 150 mA. If both were allowed to operate together, the maximum would be 120 + 150 = 270 mA, exceeding the guide’s 250 mA limit. Do not connect or enable supplies together simply because their sum is lower than the limit: first confirm the combination, any integrated-supply settings and configuration instructions with the manufacturers.
Do the addresses guarantee a power budget?
No. Address capacity and available current answer different questions. The Alliance’s system overview describes individually addressable control gear and control devices. A design can fit within address counts yet exceed a current budget, or have electrical margin but require another solution for its address allocation. An address plan does not replace a current schedule.
What should an integrator request before commissioning?
- List the exact part number and quantity of each bus participant, including integrated controllers and sensors.
- Request maximum bus-consumption values and the guaranteed and maximum supply-current values under the applicable conditions.
- Identify each enabled supply, whether it is standalone or integrated, and obtain instructions for any permissible combination or disabling setting.
- Check the cable topology, length, voltage drop and commissioning procedure against the specific device documentation and project requirements.
- Record the arithmetic, installed settings, later additions and measured commissioning results; an available-current calculation alone is not an interoperability test.
Product identity and project support
Ο WEHO HLG-200 series product page identifies the HLG-200-12 pictured here as an LED power-supply model. Obtain the exact lighting-load and control-interface documents before selecting a complete system; the product image is not evidence of a DALI interface, certification or bus supply.
Frequently asked questions
Can I add the bus currents of all integrated supplies?
Include every enabled supply in the maximum-current check, but confirm the manufacturer’s instructions permit the particular combination. Do not assume supplies can be paralleled or disabled.
Can I use LED wattage to estimate control-bus current?
No. Request the bus-consumption figure for the actual control device. LED load power and DALI control-bus current describe different circuits.
Planning a lighting project? Send WEHO the exact lighting load, intended control method and required documents. Ask for model-specific information and have the DALI integrator verify the bus budget and compatibility. Επικοινωνήστε με την WEHO.
