This page describes the Lobaro wireless M-Bus gateway firmware, called app-nrf9160-wmbus, which is executable on different hardware variants sold as different products.

Overview

The Lobaro wireless M-Bus gateway firmware collects consumption values from up to 500 commercially available water meters, heat meters, heat cost allocators or similar with 868 MHz wireless M-Bus radio interface or Sensus RF Bubble Up and forwards them encrypted via NB-IoT, LTE-M1 cellular radio or LoRaWAN networks for further processing on the Internet.

Forwarded meter values are transmitted, optionally additionally encrypted via DTLS, to a shared or private instance of the Lobaro IoT platform and can be viewed there or downloaded as a CSV file. Alternatively, standardised APIs such as MQTT, HTTP Push, SFTP or a REST interface are available to connect downstream systems or platforms easily and securely. When using LoRaWAN, the Lobaro Platform is optional. When using NB-IoT or LTE-M, on the other hand, it is mandatory. This requirement is explained in the Lobaro IoT Platform FAQ.

Thanks to the new NB-IoT mobile radio, optimised for sensor data, remote reading even works in places such as basements where smartphones have poor or no reception.

Supported Hardware Platforms

This firmware, following the naming sheme app-nrf9160-wmbus-TZ2-VERSION-HARDWARE, exists in versions targeted for different Lobaro hardware. On all hardware the workflows and functionality is the same. If a certain firmware feature is not available on a specific hardware variant, this will be indicated separately.

Basic Workflow

1. The gateway remains in power-saving mode most of the time.
2. The unit wakes up at flexible configurable time points, e.g. every hours, every 7th day or every Monday.
3. Encrypted wireless M-Bus (868 MHz) telegrams are received for a configurable duration and buffered.
   1. Reception can be limited to certain devices and types by means of filters.
4. After the configured collection duration has been reached, the meter data reception is stopped again.
5. The buffered meter telegrams get uploaded afterwards on the Internet
   1. NB-IoT, LTE-M1: Data is send using UDP, DTLS (optional) and CoAP to the Lobaro IoT platform instance. 
   2. LoRaWAN: Data is send as Class A uplinks to the downstream LoRaWAN server / platform on the internet. Metering telegrams may be spliced and send in multiple uplinks.
6. The Lobaro Platform can perform decryption the consumption telegrams with stored keys.
7. The consumption values are available in table views inside the Lobaro Platform and as a CSV download 
8. Data may be forwarded from the Lobaro Platform to additional systems and platforms using one of these APIs: MQTT, REST, HTTPS-PUSH or SFTP.

Network Selection Parameters

WAN

This parameter can be used to set whether cellular IoT (NB-IoT, LTE-M) or LoraWAN is to be used for data transmission. With LoRaWAN, the type of network join can also be defined (ABP vs. OTAA). 

WAN

lte

Remote Configuration

• Devices using LTE-M or NB-IoT can be configured easily using the interface (search for 'config tab' inside devices) in the Lobaro Platform.
• Devices using LoRaWAN can configured by sending downlinks on port 128:
  • A single config parameter can be changed by sending S<parameter>=<value>
  • For example: changing the device to switch to using LTE-M or NB-IoT, you would change the parameter "WAN" to "lte" by sending:
    "SWAN=lte"
  • Depending on the used LoRaWAN network servers convention you will to encode this string in Base64 as "U1dBTj1sdGU=" or Hex as "5357414e3d6c7465".
  • AdditionalI Information: LoRaWAN Downlink Configuration

Compatible wireless meter protocols

• Wireless M-BUS S1, C1 or T1 modes, e.g. unidirectional 868 MHz modes following DIN EN 13757-4.
• Open metering specification (OMS, Annex O): PHY_A - 868 MHz (uplink only)
• Sensus RF Bubble UP - Manufacturer specific (Xylem Inc.) radio protocol

433 MHz variants available on special sales request:

• Open metering specification (OMS, Annex O): PHY_B - 433 MHz (uplink only)
• Sensus RF Bubble UP 433 MHz - Manufacturer specific (Xylem Inc.) radio protocol

Anbindung an das Smart Meter Gateway (SMGW)

• SMGW Anbindung 🇩🇪