While KNX is good for controlling many types of building services it’s not ideal for lighting control. Native KNX dimmers are available but the choice is limited (although improving over time) and they tend to be expensive whereas the alternative DALI standard is much more commonly used for dimmable lighting – and there’s a good choice of ‘gateway’ devices which bridge between the KNX and DALI protocols so it’s not unusual to see both standards combined on one project. A DALI-KNX gateway presents all the DALI devices on the KNX bus so they look like KNX devices from a control standpoint, offering the best of both worlds.

The DALI standard is broadly equivalent to KNX in as much as:

• It is not owned by any single manufacturer and it is common to mix-and-max devices from different companies in one installation
• Communication is across a dedicated ‘bus’ network (separate from the KNX ‘bus’, using a different type of cable)

A good illustration of the flexibility of the DALI standard is shown in the photo below (a real example from the Utility Room in the House). There are 5 different DALI controllers of 3 different types:

1. The white-and-green AURORA AU-DATR400 controller on the far left generates a dimmed 230V AC output suitable for table lamps with dimmable mains-voltage bulbs (connected via round-pin plugs; this one is for the circuit in the Dining Room)
2. The two cream-coloured boxes with white labels are TCI DC MAXI JOLLY HV DALI controllers which generate constant-current DC outputs suitable for LED downlights
3. The two grey boxes with silver labels are Ecopac ELED controllers which generate constant-voltage DC outputs suitable for LED tape striplights
   • The one marked EH_LD_02 is a 100W, 24V unit for the recessed LED strip in the Entrance Hall
     • 24V is preferred for longer runs of LED tape
   • The one marked GB_LD_01 is a 100W, 12V unit for the LED strip around the dropped-ceiling in the Ground-floor Bathroom (which is silicone-coated for protection from high humidity)

DALI by Marsh Flatts Farm Self Build Diary is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.