How to send M-Bus over LoRa to Modbus RTU

Hi All,

I am from Singapore and I believe we use 920 MHz over here.

We sell some M-Bus devices; in my industry, it is common to use Modbus RTU as the signal input for DDC controllers, we normally do this by looping all the wires of M-Bus devices together and finally connecting them to an M-Bus to Modbus converter gateway which converts all the M-Bus signals to Modbus RTU, the gateway is connected to the DDC controller through an RS485 cable.

However, there are more enquiries asking for wireless solution. I am trying for explore and find an option where we can do the following:

  1. M-Bus device connect to an M-Bus to LoRa converter/transmitter
    2.LoRa transmitter to send data over LoRa to data concentrator that will give Modbus RTU output
  2. Connect Data Concentrator to DDC controller through RS485 cable

Is this method possible?

Currently many IoT solutions provider only provide the solution where we can convert M-Bus to LoRa and send the data to a LoRa gateway which will use a network server to send the data to a cloud application server. However, this cloud application server uses the IoT provider’s propriety smart metering platform, and we are required to pay monthly fees for this which many clients do not want.

Hope someone can advise.

Best Regards,

Very probably - many projects nowadays are like Lego Technic - you plug the right bits together - but it will depend on the constraints of downlinks - messages from the application to the BMS/DDC

What range do the transmissions have to reach? Is there established LoRaWAN coverage? Will end users want to rely on community systems?

Will the savings cover the cost of the research, development & commissioning of such a system?

Hi Nick,

Thanks for the reply. Most of these projects are within buildings, and because Singapore is a very small country, we do not need to cover long distances. I do not know about Singapore’s LoRaWAN coverage as I am new to this, I suppose most clients would prefer to have private networks.

I do not know if the savings is worth the effort, but many projects do not want to consider SaaS, they do not want to pay recurring fees.

I believe it’s ~50km wide - that’s a long distance for low power radio at ground level.

Wondering then how you’d pay for the gateways plus the network & application server? Transmitting data via radio will need something to receive the signal and pass it along.

That said, there are a dozen gateways showing up on the map.

That would make the scheme not really on topic here, as this forum is for the TTN shared community public network.

It’s not really very clear what you are trying to send, if you can distill the essence of the traffic down to small, infrequent not necessarily reliable messages then LoRaWAN might be a solution. But generally LoRaWAN and TTN in particular are for drastically lower and more intermittent data rates than most other wireless schemes.

It is not the solution to every problem.

Hi Daniel,

You can easily send data via lora uplink by following procedures:

  1. From your M-Bus to Modbus gateway connect by RS485 into a Lora Uplink Node.
  2. Then you can register this Lora Uplink Node in TTN or other Lorawan network.
  3. Alternatively you can use an embedded lorawan network server to directly send data to your server if you dont like to pay extra for data or cloud fees.

Hope this helps. If you need further details feel free to contact me.