[OH3/KNX] Multiple Things

  • Platform information:
    • Hardware: RasPI
    • OS: OpenHabian
    • openHAB version: 3.0

I have been using OpenHab 2.0 for quite some time and starting a fresh installation for OH3.

Apparently there are two way you can handle KNX Bindings :

  • 1 Thing (The Gateway), Multiple Channels/Things (One for each Address to simplify)
  • Multiple Things (One per address) with only One Channel and One Thing

Is my understanding correct ? Any reason why I choose one or the other pattern ?

Thanks,

Simon.

In fact, you can use one thing for all channels, but this will be a generic thing. You can’t use special functions such as online/oflline messages. You can’t use frequent reading at all, as this is a per thing defined function and will increase use of the bus in a severe way.

The thing model is meant to build a more or less exact image of the hardware, so, in general, you should use one thing per device. If you have a knx device to use in the cabinet (i.e. REG in german) you will create one thing for this device, no matter how many channels are controlled by this device. Then create one channel per channel for each function (switch, energy, whatever)
Please be aware that you can set an individual address per thing (you must not set this at all if defining a generic thing), this will allow additional information about the device.

I have one thing per knx device and multiple channels mapped to the various input/outputs on the actuator.

I also have a bridge for each line and a multicast.

I used to have everything under a single thing but I have about 250 knx devices so I wanted
It to be easier to follow.

No idea whether this is right…!!!

I like the way you put it !
I have a single line, but putting one thing per knx device seems like a good idea, and close to the Concepts vision of OpenHab

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So if I understand correctly your message if to create only one thing (the gateway / REG), and then one channel for each function (RollerShutter, Lamp, , Switch, …).

In my Setup I have, One gateway (Hager TH210), Several Output actuator (Hager TXA608), and of course switches (Hager WXT306). Each individual Light or RollerShutter has a KNX Adress (X.Y.Z).

If I follow your advice, I will have one thing for the device, and one channel for each light or RollerShutter. Is that correct ?

If I listen to @crystollic , I would rather have one thing for each Actuator, with one channels mapped to this Thing for each Light or RollerShutter actully linked to this actuator. This seems to also makes sense !

No, please read carefully.

In fact, we both wrote more or less the same.
However, I don’t recommend to use more than one Gateway for one knx bus, as it’s possible to build a loop accidentally.

I recommend one thing per device (i.e. a thing per individual address) and one channel per channel/function.

As an example… one device TYA628C Aktoren Rollladen/Jalousie | Hager is one thing with 8 rollershutter channels. These are linked to 8 rollerhutter Items to control 8 blinds (or something similar)

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OK thanks for the precision.
It looks odd to me that you would add a physical thing for one device, but maybe have some GA that are mapped to two different physical devices … Maybe this is a mistake from my part on my KNX/ETS setup …
But I’ll try to make it work with your advice :wink:

Oh, next level :slight_smile:
To operate each individual channel of each actuator, you have to have exclusive GA for each command CO. Furthermore, you have to have one exclusive GA per status CO.
Of course it’s ok to have additional GA for command CO which are set to more than one device or channel. But these GA are to control groups of channels, it’s best either not to use them at all from openHAB or to set them in another generic thing without reference to any device.

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