DALI-2 stores scenes directly on the electronic control gear (ECG) memory — not on the gateway. This means scene execution is instant (the gateway sends one telegram; all ECGs on the bus respond simultaneously) and works even if the KNX bus temporarily drops. Understanding how scenes are stored and recalled is fundamental to professional DALI-2 installation.

DALI-2 scene basics

Each DALI-2 ECG can store 16 scenes (scene 0–15). A scene is simply a dimming level (0–254, where 0 = off, 254 = 100%). The gateway programs each ECG's scenes during commissioning. Once stored, recalling scene 3 on group 2 sends a single DALI broadcast: all ECGs in group 2 immediately fade to their stored scene-3 level.

DALI groups

DALI-2 supports 16 groups (group 0–15). An ECG can belong to multiple groups simultaneously. Typical grouping in an office: Group 1 = open plan north, Group 2 = open plan south, Group 3 = meeting room, Group 4 = kitchen. The gateway's ETS parameters define which ECG short addresses belong to which groups.

Step-by-step scene setup with MDT DALI Gateway

First, commission the DALI bus in ETS: add the MDT gateway device (e.g. TYA-612-07.01), run DALI scan to discover all ECGs, assign short addresses (0–63). Then: set group memberships per ECG (each ECG → Groups tab → check the groups it belongs to). Set scene values: ECG #1 → Scene tab → Scene 1 = 80%, Scene 2 = 40%, Scene 3 = 0%. Repeat for all ECGs. Program scenes to DALI bus (ETS download). Link KNX scene recall: KNX group address 0/3/1 (8-bit scene value) → gateway communication object "Scene input" → DALI scene recall command.

Scene linking in KNX

The MDT gateway's "Scene input" communication object accepts a KNX 8-bit scene value (DPT 18.001). This maps KNX scene numbers to DALI scenes. KNX scene 1 → DALI scene 0. When a KNX pushbutton sends "activate scene 1" on GA 0/3/1, the gateway translates this to a DALI "recall scene 0" command on the specified group.

Practical tips

Always use the DALI gateway's built-in commissioning tool to verify scene storage — don't just download ETS and assume. After commissioning, test each scene by sending the recall command manually in ETS online mode. For tunable white (DALI-2 DT8), each scene stores both arc power level AND colour temperature — configure both in the gateway parameters. Emergency DALI-2 (IEC 62386 Part 202) scenes are separate and override any scene recall during an emergency condition.

Common mistakes

Assigning a scene value of 255 (DALI mask value) means "no change" — the ECG ignores the scene recall for that scene number. This is useful when you want a scene to control brightness but not colour temperature. Not resetting scene storage before re-commissioning causes ghost scene values from previous installations.