Signal & Communication
My DALI signal quality is poor (yellow or red), what are the causes and how do I fix it?
By Lichtvision Engineering · Published
Short answer
Yellow means communication is still possible but outside the preferred limits, investigate before it fails. Red means reliable communication can't be guaranteed. Common causes are weak or faulty devices pulling signal levels down, wiring issues (long cable runs, missing bus termination), or an undersized power supply. Test each device individually to isolate the root cause.
What yellow and red mean
Yellow: communication works, but the margins are outside the preferred range, worth fixing before it turns into intermittent faults. Red: reliable communication can no longer be guaranteed.
Common causes
Weak or faulty devices pulling the signal levels down; wiring issues such as overly long runs or missing bus termination; or a power supply that is undersized for the line.
How to isolate the culprit
ProbitSite lets you test each device individually, so you can find the specific device or segment responsible instead of replacing parts on suspicion.
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.