Sensor and KNX Converter - how connect them together

LPWAN Industrial Gateways / Concentrators RAK7258
#1

Issue: Need help to connect my sensors

Setup:
Sensor => Milesigth EM300-TH-868M
Converter => KNX/LoRaWAN-Converter HD67D27-B2-868MHz

LoRa® Server: RAK 7258

Details: I want to connect the Sensor for temperature and humidity. In the Gateway I have create a Application and add the sensor. In the Page “Live Device Data” i can see the values they come in. In the meantime i was able to add the Converter to the Gateway. Now are two devices are connected to the gateway.

I ask the vendor of the converter and he reply: " To make the connection between your LoRaWAN device and ours, you must first create the payload association in your gateway. Once this is done, you can go to our device to indicate the number of bytes you want to go to. "

I am a beginner in LoRa and I am not understand how i can do that what the support of the vendor describe. Can someone assist me?

#2

Hey @mkolowicz ,

Can you be a little bit more specific in what is it you want to do.
You seem to have a Temperature and Humidity Node you claim to have successfully send data to the RAK7258, using the Built-in server it seems.
Seems the Modbus Converter is the one giving you trouble. If I am guessing right you want to use a payload decoder for the KNX node, however this is not something the Built-in Server supports.
By looking at pages 20 and 25 in the manual of he KNX device it would seem to me this is what you want to do, is it not.
As there is no custom decoder functionality, It is best to forward the received payload to an external MQTT broker where you can run a script to process and visualize the data. For example running a NodeRed+Grafana combo on a Raspberry pi.
Was I on the right way or you want to do something completely different?

Regards
Vladislav

#3

Thanks for your reply. Most of your statement are true. Now I explain my idea.

I want to integrate more than 1 Sensor on my gateway with the built-in server. Then I want to route the payload to KNX. I didnt need a conversion on LoRa-side. When the data is on KNX I can modifie in the visualisation.

It is possible to send the payload(s) to the modbus converter? Or I missunderstand the function of the Converter?

#4

Hei @mkolowicz ,

I think the Converter is meant to convert data acquired via measurements done by sensors or cable data network and convert it to LoRaWAN. The other way around would not work so well.
It would need to work in class C I would say and the gateway would need to forward the data to it via LoRa downlinks, which the gateway is technically not designed to do, as these downlinks are meant to be control messages rather than data transfer of measurements, etc. Technically it could be done I guess, you make the gateway act as an relay, however you would need a custom solution to do this, basically talk to the LoRaWAN Server, which the one in the RAK is not designed to do, you can only send test downlinks.
In short a LoRaWAN Gateway and the network protocol itself is not designed to have such a topology.
What would be better in your case is to make the two Nodes talk to each other in P2P mode so you can directly relay data from one to the other.

Regards
Vladislav