A KNX DALI gateway bridges the KNX building automation bus with a DALI-2 luminaire network, exposing individual DALI devices, groups, and scenes as KNX communication objects programmable in ETS6. The MDT DALI Gateway (SCN-DALI.01 or DALI-64T.01 for 64-device capacity) is the most widely used KNX DALI gateway in German and Central European KNX installations, with an ETS6 plug-in for integrated commissioning. This guide covers the complete commissioning sequence from DALI bus wiring through to scene activation and feedback testing.

MDT DALI Gateway hardware overview

MDT SCN-DALI.01: DIN-rail (6 modules wide), KNX TP connection (bus terminal, 9600 baud, 29V), DALI line output (terminal block, integrated DALI power supply 250mA), Ethernet (optional, for direct DALI commissioning without KNX programming download), 230V auxiliary supply. Maximum DALI devices: 64 (DALI Part 1 standard, 0-63 short addresses). Integrated DALI PS: 250mA, powering up to 125 DALI devices at 2mA each — in practice, limit to 64 devices (64 × 2mA = 128mA < 250mA). No external DALI power supply needed. For second DALI line: add second MDT DALI gateway on separate KNX bus (one gateway per DALI line). DALI cable requirements: YCYM 2×0.8mm² or 2×1.5mm² (any unscreened cable); maximum bus length 300m; no polarity on DALI cable (DALI is polarity-independent, unlike KNX).

Step 1: DALI bus scan and short address assignment

ETS6 plug-in access: after adding MDT SCN-DALI.01 to ETS6 project and assigning individual address, open device properties > DALI Configuration > Launch DALI plug-in. ETS6 plug-in connects to MDT gateway via KNX bus (must be online). Bus scan: DALI plug-in > Scan DALI bus — discovers all connected DALI ballasts/drivers. Each device is listed with: random address (64-bit, factory generated), device type (Type 0=fluorescent, Type 1=emergency, Type 6=LED, Type 8=colour), and current min/max level. Short address assignment: DALI standard allows two methods — sequential (assign 0,1,2...63 in discovery order) or identification (flash each device, installer labels which device is in which room). MDT plug-in: select device in list > Identify (device flashes for 5s) > assign short address. Repeat for all 64 devices. Save assignment to MDT gateway memory (plug-in > Write to device). ETS6 download: after DALI assignment, perform standard ETS6 download to MDT gateway — this writes KNX communication objects AND DALI group/scene configuration simultaneously.

Step 2: ETS6 group object configuration

The MDT DALI gateway exposes KNX communication objects for each DALI device and group. ETS6 object structure: Individual device objects (per short address): ON/OFF (1-bit DPT 1.001), Absolute level (1-byte DPT 5.001, 0-255 = 0-100%), Scene recall (1-byte DPT 18.001), Actual level status feedback (1-byte, read-only). Group objects (per DALI group 0-15): identical set of objects — ON/OFF, level, scene, status for the entire group. For a typical office (DALI line with 24 luminaires in 3 groups): Group 0 = All luminaires (broadcast), Group 1 = Open-plan zone A (rows 0-7), Group 2 = Open-plan zone B (rows 8-15), Group 3 = Meeting room (addresses 16-23). ETS6 group address links: GA 1/1/0 → MDT group 1 ON/OFF, GA 1/1/1 → MDT group 1 absolute level, GA 1/1/2 → MDT group 1 scene recall. Assign GA to each MDT communication object in ETS6 Properties > Communication Objects.

Step 3: DALI group assignment in MDT plug-in

In DALI plug-in: select DALI group (Group 0-15) > assign short addresses to group. Each DALI device can be in up to 16 groups simultaneously. MDT plug-in group assignment: Group 1 (Zone A): check addresses 0,1,2,3,4,5,6,7. Group 2 (Zone B): check 8,9,10,11,12,13,14,15. Group 3 (Meeting): check 16,17,18,19,20,21,22,23. Group 0 (All): check all 24 addresses. Write group configuration to MDT gateway. Verify: DALI plug-in > Group 1 > Set level 80% → addresses 0-7 should brighten, 8-23 should remain unchanged.

Step 4: DALI scene programming

DALI supports 16 scenes (0-15) per device. In MDT plug-in: select scene (e.g., Scene 0 = "Presentation"), set level per device or per group: Group 1 = 80%, Group 2 = 70%, Group 3 = 80%. Write scene to all devices: MDT plug-in > Scene 0 > Store. Scene recall from KNX: write DPT 18.001 value 0 (scene 0 activate, bit 7=0 for activate vs bit 7=1 for query) to GA 1/1/2 → MDT gateway receives KNX telegram → sends DALI "Recall Scene 0" command to all DALI groups on line → luminaires recall their programmed scene 0 levels within 50ms. ETS6 Group Monitor verification: write hex value 0x00 (scene 0 activate) to GA 1/1/2 → observe DALI luminaires changing to scene levels. Scene 0-63 in DPT 18.001: bits 0-5 = scene number (0-63), bit 7 = 0 activate, 1 = store (never use store from ETS6 Group Monitor in production — use MDT plug-in for scene storage).

Step 5: Feedback and status verification

MDT gateway feedback: after any DALI command, the gateway reads back the DALI actual level from each device and updates the KNX status communication object. Status latency: typically 200-500ms after command (DALI query cycle time). KNX status GA (e.g., GA 1/1/10 for Group 1 actual level, DPT 5.001): monitor in ETS6 Group Monitor after writing level command → verify value updates within 1 second. Important: DALI actual level feedback is the average of all devices in the group — if one luminaire fails (output = 0 while others = 80%), the feedback shows a lower-than-expected average. Individual device status: MDT DALI plug-in > Device status tab > shows actual level per short address — use during commissioning to identify any device not responding. DALI fault detection: if device short address responds in scan but fails to respond to level commands: check DALI cable connection to that luminaire, verify DALI ballast/driver power supply (separate mains supply, not from DALI bus). MDT gateway DALI fault report: communication object "DALI short circuit" (1-bit) and "Device failure" (per short address, 1-bit) — link to ETS6 group addresses for fault monitoring in BMS or Gira X1 visualisation.