DPT 18.001 scene telegram architecture

KNX scene recall and store commands are carried by a single 8-bit telegram using data point type DPT 18.001 (scene control). The 8-bit byte encodes both the scene number and the command type, allowing recall and store to share the same group address with no ambiguity.

8-bit scene telegram (DPT 18.001):

  Bit 7:  0 = Recall scene (activate stored state)
          1 = Store/Learn scene (save current state)

  Bits 6: reserved (always 0)

  Bits 0–5: Scene number (0–63)
            0 = Scene 1 in ETS6 (zero-indexed)
            63 = Scene 64

Examples:
  Recall scene 1:  0b 0000 0000 = 0x00 (bit 7=0, scene=0)
  Recall scene 4:  0b 0000 0011 = 0x03 (bit 7=0, scene=3)
  Store scene 1:   0b 1000 0000 = 0x80 (bit 7=1, scene=0)
  Store scene 4:   0b 1000 0011 = 0x83 (bit 7=1, scene=3)

Note: ETS6 displays scene numbers 1–64 (1-indexed).
      DPT 18.001 encodes 0–63 internally (0-indexed).
      ETS6 handles the offset automatically.

The recall telegram instructs all actuators linked to the scene group address to load their stored preset values simultaneously. The store telegram, sent only during commissioning or end-user learn mode, writes the current actual values of all linked actuators into the scene memory at the specified scene number.

Push-button scene controllers

Dedicated scene push-button controllers send DPT 18.001 recall telegrams on short press and optionally store telegrams on long press. They require no actuator functions — each button is configured in ETS6 to send a fixed scene number telegram to the scene group address.

DPT 18.001 in ETS6: scene GA structure

The scene group address (GA) is shared by all devices participating in a scene — the push-button sends to it, and all actuators receive from it. A single scene GA can address unlimited actuators, making large scene configurations with dozens of channels practical with a single telegram per scene recall.

Actuator channel configuration (e.g. MDT dimmer channel 1):
  Parameters > Scene > Scene enable = Yes
  Scene 1 dim level = 80%
  Scene 2 dim level = 40%
  Scene 3 dim level = 100%
  Scene 0 dim level = 0% (Off)

Group address assignment:
  Object: "Scene" → link to scene GA (e.g. 1/5/0)

ETS6 scene GA creation:
  Main group:   1 (Automation)
  Middle group: 5 (Scenes)
  Sub address:  0 (Zone A all scenes)

All actuators in Zone A linked to GA 1/5/0.
Push-button also linked to 1/5/0 (send).
Scene controller also linked to 1/5/0 (send).

On scene GA telegram receipt:
  - Dimmer: loads preset dim level for scene number
  - Switch: loads preset on/off for scene number
  - Blind: loads preset position + slat for scene number
  - Thermostat: loads preset setpoint for scene number

Each actuator channel must have scene mode enabled and a scene number assigned in ETS6 parameters. If the scene number in the telegram does not match any enabled scene on an actuator, the actuator ignores the telegram — it does not reset to a default state. This selective response allows zone-specific actuators to ignore building-wide scene numbers they are not assigned to.

Scene number assignment conventions

A consistent scene numbering convention across the project prevents errors during commissioning and simplifies fault-finding. The following standard assignments are widely used in European commercial KNX installations and should be defined in the project specification before ETS6 programming begins.

Scene GA structure for zones and building-wide recall

For multi-zone buildings, a hierarchical GA structure enables both per-zone scene recall (from a room push-button) and building-wide scene recall (from a BMS or master panel). Actuators are linked to both their zone GA and the building-wide GA — they respond to either.

1/5/0   Zone A scenes (floor 1 open office)
1/5/1   Zone B scenes (floor 1 meeting rooms)
1/5/2   Zone C scenes (floor 1 reception)
1/5/3   Zone D scenes (floor 2 open office)
1/5/10  Building-wide scenes (all zones)

Zone A actuators → linked to 1/5/0 AND 1/5/10
Zone B actuators → linked to 1/5/1 AND 1/5/10
Zone C actuators → linked to 1/5/2 AND 1/5/10

Zone A push-button → sends to 1/5/0 only
Building master button → sends to 1/5/10

When building GA 1/5/10 Scene 5 "Night" is sent:
  → All zones receive and load their Scene 5 preset
  → Zone A dim level for Scene 5: 5%
  → Zone B dim level for Scene 5: 5%
  → Zone C dim level for Scene 5: 10% (security desk)

Learn mode protection

Learn mode (store mode) allows a long press on the scene push-button to overwrite the stored preset for a scene with the current actual values of all linked actuators. While convenient for end-user fine-tuning, it creates a risk in professional installations: an accidental long press on the wrong button permanently overwrites carefully tuned scene presets.

Scene priority and conflict resolution

A scene recall telegram and a direct actuator command (e.g. a dim command from a presence detector) may conflict when both are sent in close sequence. KNX actuators handle this through a scene priority setting and a scene hold period.

Actuator scene priority parameter:
  High   — scene recall overrides any pending direct command;
            direct dim/switch commands blocked for hold period
  Normal — scene recall and direct commands treated equally;
            last command received wins

Scene hold period (scene lock time):
  Configurable: 0 seconds (disabled) to 120 seconds
  Recommended:  30 seconds for meeting rooms
                0 seconds for residential (user expects
                direct control immediately after scene recall)

Conflict scenario — meeting room:
  1. User presses "Presentation" scene → dim 80%
  2. Presence detector triggers dim command → 100%
  3. With High priority + 30s hold:
     Step 2 is blocked for 30 seconds.
     Presentation scene maintains 80% for 30s.
  4. After 30s, presence detector resumes normal control.

KNX time module integration for scheduled scenes

The MDT Logic Module SCN-LOGM.01 and similar KNX time modules can send DPT 18.001 scene recall telegrams on a schedule — no external BMS or IP server required. This enables automatic morning, evening and weekend scene presets using only the KNX bus.

The time module operates autonomously on the KNX bus — scheduled scene recall functions even during BMS or server downtime. Summer time (DST) switchover is handled automatically if the logic module is configured with DST correction enabled.

Commissioning workflow and scene register

Professional KNX scene commissioning requires a scene register spreadsheet maintained alongside the ETS6 project. The register defines every scene before programming begins and serves as the test matrix during handover verification.

Scene #  | Name           | Scene GA | Participating actuators       | Preset values
---------|----------------|----------|-------------------------------|------------------------
1        | Presence/Work  | 1/5/0    | Dimmer ch1, Dimmer ch2,       | 100%, 100%,
         |                |          | Blind A, Thermostat           | pos 0%, 21°C
2        | Presentation   | 1/5/0    | Dimmer ch1, Dimmer ch2,       | 80%, 60%,
         |                |          | Blind A, Thermostat           | pos 70%, 21°C
3        | Video          | 1/5/0    | Dimmer ch1, Dimmer ch2,       | 20%, 0%,
         |                |          | Blind A, Thermostat           | pos 100%, 21°C
0        | Off            | 1/5/0    | Dimmer ch1, Dimmer ch2,       | 0%, 0%,
         |                |          | Blind A, Thermostat           | pos 0%, 18°C

Use ETS6 copy-paste-properties to apply scene configurations across multiple actuators of the same type: configure one dimmer channel completely with all scene presets, then Copy Properties → Paste Properties to remaining dimmer channels. Adjust only the per-room GA assignment. This workflow reduces programming time for 60-channel installations by approximately 95% compared to configuring each channel individually.