Scene values of KNX Switch Actuator

[IbrahimYucel]

Hello All,

I have completed a KNX project 6 years ago and the MTN649208 actuators were used. The scene function was used to control outputs. 

The problem is the actuators are forgetting the relay state of recalled scene after a while. There are more than 50 actuator on the system and this problem is getting from various modules. It is fixed after re-download the program from ETS. For example, the relay should be pressed on scene 3 and it is ok after download but it goes to unpressed when selected scene 3 after a while. 

I attached an image of the configuration.

Thanks in advance for your support.

Regards,

Ibrahim.

[Heribert_Dölger]

Hello Ibrahim

Possible reason for this behaviour might be that the actuator is receiving a scene learn command. MTN649208 supports learning of new scene values with a scene command with first bit set to value "1". If the device that is recalling the scene (for example pushbutton) supports scene learning as well you usually can execute learning of new scene values by a long press of the button. If such a learning command is recieved by the actuator it will learn the current status of all channels that are part for the respective scene as new values of this scene.

The structure of the scene command is L X D D D D D D
L...Learnbit
X...not used
DDDDDD...recalled scene address

If learnbit is set to 1 the current status of all channels belonging to the scene address (defined in DDDDDD) will be the new values of this scene. This might explain why the values of the initial scenes are no longer present. 

You might double-check if learning of new scene values is activated in your pushbutton (or other device) that is recalling the scene.