Commissioning & Scanning
I installed all my DALI devices but nothing happens, how do I get control of my lights?
By Lichtvision Engineering · Published
Short answer
Start at the basics. Measure the DALI bus voltage: it should be around 16 V and never below 9.5 V (DALI-2 standard). Make sure a DALI bus power supply is present, some controllers include one, some don't. If the voltage is correct, send broadcast commands (All On / All Off) and watch which devices respond. The ones that stay dark usually have a wiring problem.
Step 1, check the bus voltage
Measure the DALI bus voltage at the controller terminals and again at the far end of the line. It should sit around 16 V and must never drop below 9.5 V (DALI-2 specification, IEC 62386-101). A voltage that is missing, too low, or that collapses under load points to a power-supply or wiring problem and there is no point looking at logic or addressing until that is fixed.
Step 2, confirm there is a bus power supply
A DALI line needs an active bus power supply that injects the standard current onto the bus. Some controllers integrate one, many do not, and DALI gateways for KNX or BACnet often expect an external supply. If no supply is present, devices will be powered for their lighting function but the bus itself stays silent, so nothing on the line will communicate even though the lamps are mains-powered. Check the controller datasheet and, if in doubt, add a dedicated DALI bus power supply rated for the number of devices on the line.
Step 3, broadcast and watch what responds
With voltage confirmed, send broadcast commands (All On / All Off) and walk the installation. Devices that react are wired and powered correctly; devices that stay dark almost always have a wiring fault, swapped polarity on the input, or a missing neutral. Note the dark luminaires by location, this is your shortlist for the next site visit.
Step 4, check polarity and bus continuity
DALI is polarity-insensitive at the device, but a break in the bus, a short between DA+ and DA-, or a stray mains connection on the DALI pair will silence whole branches. Disconnect suspicious branches one by one and re-broadcast. The branch that restores communication contains the fault.
How ProbitSite helps
ProbitSite measures the bus voltage, monitors current draw, and sends broadcast commands directly on site, so you can confirm the basics, watch which devices respond, and locate dark segments before involving the controller or main commissioning tool.
Diagnose DALI issues like this in seconds
ProbitSite is the DALI-2 certified handheld multimeter built for exactly this kind of on-site fault finding.