Lighting Issues: Flickering, Flashing, and Unexpected Power Changes

When clients report lights changing on their own, gathering precise details is crucial if you have not witnessed it, first hand. 

These issues can manifest in many ways.  Here are some examples:

• Gradual changes triggered by light sensor adjustments
• Flickering caused by unstable power supplies or ballasts
• Lights cycling on and off due to occupancy detection
• Configuration of lighting control causing unexpected turn offs (e.g a light being controlled two different ways, looping sequences that are misbehaving, etc)
• Lights momentarily going into lamp failure and recovering
• Lights resetting as a result of a crash
• Switching hardware providing bad signals to control devices, causing them to act.
• Lights misinterpreting control device commands and turning on as a result.

Given the complexity of lighting systems and the general nature of the fault, the root cause can lie with every component in the system:

• AC power supply
• DALI communication line
• DALI controller functionality
• The light fixtures themselves

Without detailed information about the specific behaviour, troubleshooting these varied issues becomes significantly more challenging.  Clients often unintentionally provide misleading descriptions of lighting issues simply because describing technical faults of this nature is unfamiliar territory for them. Therefore, helping clients provide thorough descriptions of what they observe is essential for effective diagnosis and resolution.  

Basic steps to diagnose the issue:

• Obtain the best information possible from the source of the report.
• Check the issues log to see if the system has logged system failures against the lights 
• Verify that the problem lights do not have a configuration that can cause them to unexpectedly turn off.
• Run a dali monitor and try to obtain a log at the time the issue occurs.

A note on lamp failure:

It is important to recognise that while devices report lamp failures to the controller, this reporting system has limitations. The absence of a failure report doesn't guarantee that all physical components (including the DALI line, power supply, and lamp) are functioning correctly.

DALI testing specifically focuses on how devices respond to dead or missing lamps. However, our field experience shows significant variation in how devices handle failure reporting:

• Some devices consistently report lamp failures throughout their lifespan, even when the lamps are working properly
• Others may never indicate a failure until a lamp completely stops working

Therefore, lamp failure reports should be considered just one indicator of system health, not a definitive measure of overall system functionality.