Hi, can you recommend a good value for money KNX to something converter, that would allow me to use an existing KNX system controlling a pump station to read out inputs and set outputs?
I was thinking Modbus TCP to KNX gateway, since it seems that an X20 system does not talk KNX at all.
I inherited a Siemens Synco RMS705B system which is a complete disaster when it comes to external connectivity (but it was cheap, which is why the installer used it I presume).
Hi!
Correct. B&R does not offer an interface card for the direct connection of KNX modules. Furthermore, there is no X20 module like X20CSxxxx with EIB/KNX interface. If you want to control KNX components with a B&R controller, a gateway, e.g. KNX <=> Modbus TCP or KNX <=> Modbus RTU, is necessary.
These gateways are configured with ETS (EIB/KNX configuration software).
From B&R’s point of view, the Modbus TCP gateway is the most cost-effective because no additional hardware (e.g. IF card) is required.
Best greetings Stefan
Is there some ethernet based KNX Gateway? Like a MQTT<=> KNX ?!
Would be a possibility using this mqtt library, which is not officially supported but works well for me!
Hi Marcel !
I would like to help you here too. But EIB/KNX is not a B&R product. In addition, building automation is not a B&R focus. Therefore, we do not know these products. I think your question would fit well in a KNX forum.
Note: https://www.iobroker.net supports both KNX and MQTT. It seems suitable for this application. But it requires training time.
Kind regards Stefan
I was just throwing in ideas for the OP, I don’t use KNX 
Best regards!
oh yes. The use of a KNX mqtt gateway like iobroker (preferred for users with mqtt experience) is also possible. Sorry Marcel
Thank you all. I shall try to use a ModbusTCP-KNX gateway, probably this one. (If linking external products is not allowed, I apologize and moderator please delete the link)
It is a bit of a shame that X20 does not talk KNX in a small IO slice such as IO-Link. I fully understand the “we are not in building automation business”, but I am trying to force this one factory to full B&R, since the implementation of multiple systems is a disaster and nothing talks to anything else.
B&R ecosystem is great, compared to DCS/SCADA systems even cost effective (although that is not difficult, and no, not interested in going full APROL), it just seems I will have to standardize on ModbusTCP gateways and convert existing island of “automation” into simple IO stations and go from there.
Having said that, both Modbus RTU and Modbus TCP implementations could be much more user friendly, the first setup takes ages to do, sadly. I do understand, however, that talking to such devices is nowhere near B&R core interests.
If the gateway works, I shall report back to help out others.
I marked your reply as a possible solution. You can get in contact to your B&R local office and explained to them your usecase. maybe your idea will be takes as a good new product request.