Linking KNX & Hue Binding - No command when listening group address changes

Hi all,

Happily using openHAB 2.1 I have a question regarding the following configuration:

Switch 	Light_Office { channel="hue:0210:00123456:6:switch", knx="1/1/80+1/0/80" }

Where 1/1/80 is the KNX main group address (switch object) and 1/0/80 is the group address of the “room light control” (switches all lights in the room to off). When I send ON/OFF to 1/1/80 the hue light is switched ON/OFF correctly. But when I send ON/OFF to 1/0/80 (the room) the hue does not receive the command.

I think the item receives the update but the “link” seems not to work for listening GAs:

[ItemCommandEvent] - Item 'Light_Office' received command OFF

Is this by design or is this a bug?

As a workaround I configured an additional item only for the room GA:

Switch	Light_Office_Helper { channel="hue:0210:00123456:6:switch", knx="1/0/80" }

Unfortunately I have more listening GAs (like story, house) so this approach becomes tedious.


I would not call it a bug, as I’m pretty sure this is due to the fact, that openHAB is not able to differ between commands and state updates from knx (there is no way to do this). In knx a second group address is always “receive only” and maybe this (lack of forwarding the command) is the consequence.

I would suggest a rule to guarantee the forwarding:

Switch Light_Office_Hue { channel="hue:0210:00123456:6:switch"}
Switch Light_Office     { knx="1/1/80+1/0/80" }
rule "Office Light"
    Item Light_Office received command

Thanks @Udo_Hartmann,

I basically expected the same behavior as for KNX actuators: There you can add several group addresses to the switch object function and all will trigger the actuator. Why else would I need multiple KNX group addresses on the link?

Thanks to your suggestion I helped myself with the following rule:

rule "Office Light Helper"
    Item Light_Office received update

This way I don’t need the second item definition.

Right. I wasn’t aware the behavior of openHAB had changed in question of this particular detail.
As far as I remember, there was a time when sendCommand() triggered a received update, but as the documentation states, at least since OH2 this isn’t the actual behavior.

When looking at knx, keep in mind, that knx will only send on the first GA set to an object, so even knx distinguishes between first and following addresses.

When openHAB receives a command from the second GA, it would send this command straight back to knx, so this would be a loop.