A scene is a configurable state of one or more controllable elements. The term scene alone is not clear enough, so more precise terms are used in the following to make it clear which aspect is meant. X2B can handle scenes both internally (technology-independent) and via KNX, also mixed if required.

Two controls are provided by X2B for this purpose, the scene controller (holds the scene composition and states) and the scene button (activates or learns scenes).

A scene number channel is central to scene control; this can be an internal channel or a KNX channel (usually referred to as a scene object in KNX).
Each time the scene number channel is updated with a valid scene number (1-64), the scene is activated. If a negative scene number is received, a scene controller attached to it will save the current status for this scene number (“learning”).

Required objects and their function #

Scene number channel: A channel via which commands (scene numbers) are sent and received. This can be a KNX channel (17.001 or 18.001) or an internal channel (virtual interface).

Scene controller: A control dfrom X2B in which the scene composition is configured and which scene number channel controls the controller. If only KNX scenes are to be controlled, no scene controller is required (the scenes must then be programmed purely on the KNX side). A scene controller saves one state per scene number for its scene compilation and restores this state for the compilation on call. The controller receives the command to save (=learn) or create (=activate) the status via the scene number channel.

Scene button: A simple control from X2B that outputs commands (scene numbers) to a scene number channel. The scene button must be linked to a scene number channel and the scene numbers are configured in the button.

Interaction with KNX #

If the scene number channel is a KNX group address, this must be of data type 17.001 or 18.001 and should be configured as write-only (otherwise unwanted scene activations may occur when X2B/the KNX interface is started). When a KNX telegram is received, the scene number is converted accordingly and if the “Set” flag (only for 18.001) is set, the scene number is negated. When writing the scene number channel from the X2B side, the scene number is prepared accordingly for KNX and sent as a telegram. It does not matter for X2B whether the group address is updated by a group read response or a group write. Only group writes are sent from X2B.

Behavior:

If the value is invalid (outside the range -1 to -64 or 1 to 64), no KNX telegram is sent.

Scene controller / Compilation of a scene in X2B #

The controls that belong to the scene are defined in a scene controller. When a “Learn” command is received (negative scene number appears in the scene number channel), the scene controller saves the current status of the assigned controls under the scene number. When an “Activate” command is received (valid, positive scene number appears in the scene number channel), the scene controller restores the saved status for the scene number.

If the scene controller has not saved a status for a participating control, the control remains unchanged (nothing happens). This occurs if the scene number has not yet been learned or the scene composition has been changed after a scene number has been learned. If a control is removed from the scene composition, the scene controller will no longer control it when a scene is activated, even if the scene has learned a state for the control.

If a scene controller is deleted, all scene data stored in this controller is also lost.

Scene button / activating and learning scenes #

A scene button can be used to activate or learn scene numbers. As one scene button can activate a maximum of two scene numbers, several scene buttons may be required to activate all scenes.
To learn scenes, assign a scene button with a learn command, set the desired status and then press the scene button. It is currently not possible to edit a scene directly.

Controllable controls #