KNX und BAOS 838 Module - what now?

  • Platform information:
    • Hardware: Raspberry PI 4
    • OS: ÓpenHabian, latest Image
    • Came with Openhabian
    • Latest

I got a bit stuck here - btw. thanks for the useful information, though many of them were hard to find. So, I got the Weinzierl running with knxd, created the Bridge in OpenHab - says “online”. I also see the module from within ETS.

Well, I was always thinking of being a rather smart guy but now, I haven’t the slightest glue how to move forward. What I’m planning is the follwoing:
-) Setting up an KNX installation (no too small, its for an animal shelter) - ongoing
-) Set up OpenHab as the ONLY control system (using HapPanel)

I was trying to create an Item based on the bridge - it fails but I’m not sure if this is even the right time. I’ve studied the Weinzierl material but this isn’t much - and there I always read something “… upload group addresses by the way of the excel tool…” - what group addresses?

Can just somebody give me a few hints how to move forward or some sites to study. The Openhab documentation covers only the KNX IP Gateway stuff. And by the way, I’m new to Openhab, I’m an experienced developer but never touched Java (C/C++, Pascal, C#). So you can throw any technical terms at me, don’t hesitate.

Sorry to bother you like this - I’m a bit in a hurry and this is quite a project. Since this is for the greater good of the animals (parrots, in particular) and I do all this for free and even cover the costs for the equipment, I went to Openhab on the PI for keeping the costs to a minimum. If someone here in the community is based in Vienna, I wouldn’t mind a helping hand:-)

Thank you so far,

It’s almost straight forward. :slight_smile:
But first step is, to check if knxd is working as expected, so is it possible to send a groupswrite to the knx bus? Do you see any GA received by the group monitor?
knxd is not only a gateway to different interfaces, but also a toolbox to check and control the knx bus.

How did you create the knx Bridge in openHAB? Did you use TUNNEL or ROUTER mode? When using ROUTER mode, the bridge is always shown online (because of multicast, there is no way to check if the bridge is really connected…)

Next step after creating a bridge is to create a generic knx thing, usually one thing per device, although it’s possible (but suboptimal) to create only one thing for the whole knx bus.

Setting the individual address (German: physikalische Adresse) is not necessary but gives Online/Offline state for the thing. DON’T set fetch=true or a read Interval other than 0!

After creating a generic knx Thing (of course you set it to use the knx bridge…), go to the new thing again and create channels. You have to set the correct GA for communication, please be aware that every channel will use different GA for in and out.(e.g. a switch channel has a command GA and a state GA, both are set to the same parameter (switch has only one parameter). Of course, if a communication is one way (maybe a temperature sensor), you will only need one GA.

After setting up the Channels, you’re almost done, but you have to link the channels to corresponding Items. If there is no Item yet, openHAB will create one for you.

Hello Christian,
the initial Thing you create is just the bridge.
Then you add more Things representing the devices on the knx side within OH.
After you created such a Thing you need to add channels to the Thing - those are not created automatically. Channels are based on the knx group addresses.
These channels then link to items - I recommend to create those links by maintaining a Model.
Once you have the items linked and working go for creating Pages to be shown in Main UI


Thanks Udo - I’ve seen most of the folks here is German but communicates in English… is this a general rule? Anyway, I’ll keep it this ways but we can use our native language as well.
I’ll come up with a detailed feedback later this week - the next days are “hardware days” - I need to install the LED flood lights, momentarily switched by plugging them in/from the outlet:-))
What mode would you prefer Tunnel/Router? I read about it wasn’t sure of the difference for the particular case.

Thank you Tom, I’m pretty sure this wasn’t the last question:-))

Your’re welcome.
And yes, this is an English forum due to the fact that we want everybody to benefit from findings made by our members.

Regarding your planning on having OH being the only way to control the system:
I’d highly recommend to install in a way that all basic functions can be controlled without the use of “higher level IT”, meaning there have to be physical switches within the knx so in case there is an IT issue things are working as usual. In case of an animal shelter do not forget that it affects many creatures living there in case things are not working. And panels are sexy, but the usability with e.g. wet fingers or gloves is very bad. Physical switches should be the road to follow here, binary inputs will make this easy.
Keep in mind: Who will maintain it in e.g. 10 years ? Things often change quick and unexpectedly and people running a shelter seldom are IT specialist.
If it was my project I’d go for a completely working knx solution first. Only if this is working start adding the bells and whistles like openHAB or control panels. Plan for it (e.g. install power and ethernet where required, don’t rely on WiFi, have spare wires), but do not put it at priority level 1. First things first, rules and automation anyhow rely on a working physical basis.

Just some thoughts of my aging mind digging into lessons learned.

Hallo Tom,
you’re absolutely right here!
However, the installation itself is controlling cage lighting (parrots) and mixing, the fog system and the window shades. All this is controlled by sensors, usually.
The HabPanel runs on an Industry Tablet PC, that is mounted is the central power rack.
But yes, I’ll certainly have a digital input module for the basic functions, just in case.
Not an “aging mind” but experiences, I’d say:-))

In question of Tunnel versus Router Mode:

If the knx system is big enough, you will need more than one line and therefor line couplers.
After that you may need Areas to let the system grow to (up to) (2^16) Devices :smile: and may need Area Couplers.
knx communication is 9600 Bit/s, so not too fast :slight_smile:
If building big knx systems, it is preferred to use an IP Backbone for knx, IP backbone is 10MBit/s, more than enough to control up to 256 separate lines with up to 256 devices (one is the Router and there are four line repeaters because one line section may include not more than 64 devices).
For ease of configuration, Multicast is used for the backbone, so one IP to get them all.

Now, to get access to the knx bus, you will need an interface, early versions were RS232, then USB. But that is not as comfortable as using an IP Gateway. So, the Tunneling knx/IP Gateway was born :slight_smile:
But Stop: we’ve an IP interface already, the Router… so, in addition, every Router talks the Tunneling protocol, too, and moreover, you can tunnel over router or tunnel exclusive…

knx/IP Routers are very expensive (compared to a knx/IP Gateway), about 450 € vs. 150 € :slight_smile: BAOS 838 is much more than a simple interface to knx. In fasct, you are using only the RS232-like Interface…

knxd, on the other hand, can handle both protocols tunnel and router, at the same time. There should be no difference if using Router or Tunnel mode if using knxd,

tl;dr: small knx networks don’t need a Router interface at all.

In question of language: yepp, official community forum is english only to not limiting the community.
But there are two other forums, (this is the official one) and (the one with much, much more activity in relation to openHAB).

Well, the project took a little detour over the summer and we were focused on building the cages and movin 160+ Birds to the new location. So light was not an issue over the summer but now, as the days get short and shorter, we have to again fight the darkness. Well, I have to - the others just ask, when it’s ready:-)

Apart from a very specific question in regard to constant lighting and modelling dawn and dusk, I’ve upgraded the PI and got the BAOS module running. Ok, I hope it does - I see it with ps -ef and I do not see an error with journalctl -xe anymore.

Also the Bridge is again created and appears online. I’ve been through the KNX Binding tutorial and still not sure how to proceed. Is it correct taht I have to configure it all by the way of the writing the config file?

And what is a good test if the knxd is at all running correctly - knxtool groupswrite ip:loacalhost ?

Cheers and have a great weekend,

Good day,

I’ve got it running and I’m able to act on the KNX bus by the way of the BAOS module, however, for only one operation. After switching something, for example, the knxd quits saying:

Sep 11 09:05:20 openhabian knxd[2514]: E00000044: [32:C.ft12cemi] reset timed out
Sep 11 09:05:20 openhabian knxd[2514]: F00000105: [27:C.ft12cemi] Link down, terminating
Sep 11 09:05:20 openhabian systemd[1]: knxd.service: Main process exited, code=exited, status=1/FAILURE

The term “reset” strikes me a little - what is to reset here?

Any ideas - what kind of information do you need to make an educated duess?

Thanks to all,