What does “Device Not Recognised” state mean?

An unrecognised device is "Device Not Recognised" because it has at some point produced identification values that do not correspond with the identification values that were saved into the database for this address.   This can be the result of an actual unrecognised device being at the address or it may be an occasional bad answer from a device that then makes it look like a different device.  Generally speaking, if a device had unrecognised as its issue but has not been moved to a new address, this issue can be safely ignored.

Furthermore, it should also be noted that in lower versions of controller (prior to 1.9), this issue may persist until the controller is rebooted.  

If the device is truly unrecognised the device will be moved to an address that is not marked as used in the database. The device will then be added to the database as the owner of this new address. In the same respect, a device that owns an address in the database will always be moved back to this address by the controller to maintain integrity of the bus.

If the bus has already been fully addressed and there are no new database positions available, the controller will place the device on an unused dali address that is "owned" by a device that is currently missing. This device will show as "Device Not Recognised".

To resolve this, the user must remove 1 or more missing devices from the database to free up space for these new / unrecognised devices to gain positions in the database.

Additionally, if the user connects more than 64 devices to the bus, situations may occur where the legitimate owners of addresses may be unaddressed. In this situation, the user must correct the amount of devices present, before proceeding.