Addressing of devices on a DALI line is facilitated by triggering a randomisation function on each device to generate a large (3 byte) number. This number is used in conjunction with a block of “special commands” to allow the DALI controller to assign unique DAI short addresses (0-63) to each device on a line. Once the device has a short address, the random addresses are no longer needed and all further communication should occur using the new short address.
DOUBLING
The usage of a 3 byte randomisation scheme ensure that whilst it is technically possible for two devices to generate the same number and thus be assigned the same short address, the odds of such an occurrence is extremely unlikely. Should this arise, Ektor offers software with inbuilt routines to isolate and eliminate this issue. Please contact support@evolt-ektor.com for more details.
HINT: Remember each line has a maximum of 64 devices.
WHAT IS THE DALI LONG ADDRESS?
Some manufactures have renamed “Random address” to the word “Long Address” in an attempt to disguise or rewrite the use of the random address. Random addressing was designed to be used during the commissioning / addressing stage of the project. This feature was only designed to allow a device to be assigned a short address (0-63).
Some manufacturers however, utilise the random address to restore a line if an addressing mistake on the line has occurred. This was not the intention of the feature and complications may arise from such practices.
Listed below are some of the problems for the customer or future contractors from using this practice:
- No external or non-proprietary tools are supported (even if they are faster, better or easier)
- Risk of external tools deleting the random address and then costing the customer more money to recommission the line
- Not truly DALI compatible, as it doesn’t say in the standard not to do this, but being an open standard, anyone’s tools should be able to adjust the line without causing issues with the front end controller.
- Locked into authorized commissioning agents for the life of the project (not just the contract period)
Overall, it is Ektor’s thought that these practices should not be used as the manufactures can now use the inbuilt GTIN and Serial numbers to achieve the same result without locking out third party tools