Wireless M-Bus Gateway V4 with 4-20 mA Add-On

Description

Gateway for remote reading of wireless M-Bus meters and external sensors (4–20 mA and 1-Wire temperature sensors) via NB-IoT, LTE-M mobile radio or LoRaWAN to the Internet. Suitable for indoor and weather-protected outdoor installation.

In addition to all the features of the Wireless M-Bus Gateway V4, this variant provides:

• 2 analogue 4–20 mA input channels for industrial sensors. Each channel is supplied with an extra 12V (1W) supply voltage for sensor supply. Connection with each 4-pin channel (I+, I-, 12V, GND) can be established over a 22 cm cable connection.

• A 1-Wire interface for up to 20 temperature sensors (DS18B20). Connection with each 3-pin channel (3V, GND, DQ) can be established over a 22 cm cable connection.

Product Components

Component Info

This product is manufactured by Lobaro using the components listed below. Detailed information about the firmware and other components can be found in their respective descriptions.
Please use the links provided to access comprehensive product details.

Component	Manual / Description	Additional note
Firmware	app-nrf91-origin	See here for available firmware updates
Housing (Standard)	LoCube	122 mm (l) × 82 mm (w) × 55 mm (h)
Housing (Compact)	Compact Lobaro Box Housing	114.30 mm (w) × 59.30 mm (l) × 26.80 mm (h)
Power Supply	Battery	(Li-SOCl2) 3.6 V, 38 Ah
	External power supply (12 V or 230 V)	Please contact support@lobaro.de for further information
Optional Accessories	External Antenna (SMA) instead of internal antenna that is installed in the device per default	Please contact support@lobaro.de for further information
	IP68 encapsulation with transparent, elastic 2K silicone gel
	LoCube Backplate Wall Mounting Kit
	Pole Mounting Kit

Firmware Updates

The latest firmware can be found here:

• Download latest firmware

• For further information on how to update the device, refer to: Firmware Update.

note

A remote firmware update over LoRaWAN is currently not possible.

Product Identification

• Name: Gateway V4 + 4-20 mA
• Type: LOB-GW4-420-1W
• MPN / Ordering code: 1200588

Datasheet & Quickstart

info

Please contact our sales team.

Product specific details

LED signal patterns

The device has 3 three LEDs (B, G, R = Blue, Green, Red), labeled Status on the PCB: 🔵🟢🔴.

Patterns during booting/restart

• 🔵⚪🔴 B and R on: Device is in Bootloader Mode (not actively running, remove config adapter press reset to leave Bootloader Mode).
• 🔵->🟢->🔴 Quick cycle B, G, R for ~0.5s: Device just booted, either after power on, reset by button or software, or after a hard failure.
• ⚪⚪🔴 R flashes repeatedly on and off in 1s interval: critical failure during boot (failed to start application).
• 🔵🟢⚪ B and G on: Remote Firmware Update.

Patterns during normal operation

• 🔵⚪⚪ B flashes 1s on and 1s off in loop: building LTE connection to mobile provider. Followed by:
  • ⚪🟢⚪ Short G flash on success.
  • ⚪⚪🔴 Short R flash after connection failed.
• ⚪🟢⚪ G flash during installation mode while collecting wireless M-Bus telegrams.

Exceptional patterns

• 🔵⚪🔴/🔵🟢⚪ Quickly changing between R & B and G & B every 5s in a loop: Modem is in connection restriction mode - keep device on power, will fix itself after 30min.

Configuration

The device is shipped with default configuration parameters. The configuration can be changed via the 6-pin config port using the Lobaro USB Configuration Adapter. More information about the usage of the configuration tools can be found in our documentation.

info

Remote Configuration is also supported after initial network connection.

warning

Default Values are the firmware defaults. Depending on the application the device may be delivered with different settings.

General Parameters

Description	Key	Type	Possible Values	Default
Uplink channel selection	WAN	String	lte or lorawan	lte
Listen Cron [UTC+0]	listenCron	String	Any CRON String	0 0 12 * * *
Days without connectivity until device reset	LostReboot	Number	Any, e.g., 5	3

Detailed Description

WAN Parameter

LPWAN technology is used for connection and data communication with the backend server. This can be either cellular LTE (NB-IoT, LTE-M) or LoRaWAN.

• lte: Utilizes cellular technologies, either NB-IoT or LTE-M.
• lorawan: Employs LoRaWAN with OTAA (Over-The-Air Activation).

Limitations in LoRaWAN

• LoRaWAN uplinks and downlinks are limited to 52–222 bytes, depending on the DataRate (connection quality):
• Uplinks containing longer wMBUS telegrams are split across multiple LoRaWAN messages.
• Uplinks with numerous wMBUS telegrams may take significant time due to LoRaWAN's duty-cycle limitations.
• Downlinks with large configuration values (e.g., long whitelists) must be split into multiple messages, which can be challenging to implement.
• Limited metadata:
• Status telegrams include less information due to reduced uplink channel capacity.
• No remote firmware update capabilities.

listenCron Parameter

The listen cron specifies when the device wakes up to receive data via enabled wireless M-Bus and other radio protocols. Each listening period is followed by data upload using the configured WAN technology. The ideal interval largely depends on the device's power supply (battery-powered vs. externally powered) and the application's need for new metering data. Typical intervals range from every 15 minutes to 14 days between consecutive readouts.

CRON parameter

Learn more about CRON configuration parameters.

---

Wireless M-Bus Meter Reading

Description	Key	Type	Possible Values	Default
WMBUS C1/T1 Listen Duration [s]	cmodeDurSec	Number	Number of seconds 0 = Do not collect C1/T1 Max Value=36000	300
WMBUS S1 Listen Duration [s]	smodeDurSec	Number	Number of seconds 0 = Do not collect S1 Max Value=36000	0
Sensus RF Listen Duration [s]	xmodeDurSec	Number	Number of seconds 0 = Do not collect X-Mode Max Value=36000	0
Müller-Funk Listen Duration [s]	umodeDurSec	Number	Number of seconds 0 = Do not collect U-Mode Max Value=36000	0
WMBUS ID Filter List	devFilter	String	List, e.g. 88009035,13456035	[not set]
WMBUS Type Filter List	typFilter	String	List, e.g. 08,07	[not set]
WMBUS M-Field Filter List	mFilter	String	List, e.g. DME,ITW,SEN,QDS	[not set]
WMBUS CI-Field Filter List	ciFilter	String	List, e.g. 8a,72	[not set]
WMBUS Telegram Upload Limit	maxTelegrams	Number	Any number of max. Telegrams 0 = no limit.	0

Detailed Description

*modeDurSec Parameters

Parameters: cmodeDurSec smodeDurSec xmodeDurSec umodeDurSec

The duration, specified in seconds (e.g., 300 for 5 minutes), defines how long the device collects metering data for each corresponding wireless protocol. Each listening period is executed sequentially based on the configured durations. Once all listening periods are complete, the collected meter telegrams are transmitted using the configured WAN technology.

warning

The maximum duration that can be specified is 10 hours, i.e. 36,000 seconds. Please note that such long listening periods will drain the battery very quickly. If in doubt, please consult Lobaro.

---

*Filter Parameters

Parameters: devFilter ciFilter mFilter typFilter

Filters are applied to meters based on wireless M-Bus-related fields to determine which telegrams are collected and uploaded. These filters include:

• mFilter: Manufacturer filter – filters telegrams by the 3-letter manufacturer code included in every telegram ( e.g., LOB for Lobaro GmbH).
• typFilter: Device Type filter – filters telegrams by the 2-hex-digit code that defines the type of sending device (e.g., 07 for water meters).
• devFilter: Device filter – filters telegrams by the 8-digit ID that is mandatory for each sending device (e.g., 87654321).
• ciFilter: CI-Field filter – filters telegrams by the 2-hex-digit CI-Field included in every telegram. This field is a technical code that describes the purpose of the telegram (e.g., 8a).

These filters help refine data collection to target specific devices or device types.

More Details

For a detailed explanation, read more about telegram filter parameterization.

Blacklist

Each filter parameter can be preceded with an exclamation mark (!) to convert the whitelist into a blacklist.

This applies to the entire filter parameter, not to individual entries within the list. For example:

• mFilter=LOB will collect only telegrams from Lobaro GmbH (whitelist).
• mFilter=!LOB will exclude telegrams from Lobaro GmbH (blacklist).

---

maxTelegrams Parameter

Set a hard limit on the number of telegrams to be collected and uploaded. The firmware will stop collecting once this limit is reached, regardless of the elapsed time. This can help conserve battery life and data volume, especially if the device is located in an area with a high density of meters.

tip

When filtering for a single telegram, the parameter can be set to 1, causing the device to stop listening immediately after the desired telegram is received.

LTE Connection

Description	Key	Type	Possible Values	Default
LTE Lobaro Platform Host	Host	IP / URL	List of various Endpoints	coaps://platform.lobaro.com
LTE MCC+MNC Code	Operator	Number	e.g. 26201 (Dt. Telekom)	[not set]
LTE Band	Band	Number	3 or 8,20 or 3,8,20	3,8,20
LTE APN	APN	String	any APN	*
LTE SIM Pin	PIN	Number	4 digits pin, e.g. 1234	[not set]
LTE NB-IoT on/off	UseNbiot	Bool	true or false	true
LTE M1 on/off	UseLtem	Bool	true or false	true
LTE DNS Servers used	DNS	IP	List of DNS server IPs	9.9.9.9,1.1.1.1
Plain UDP Host	UdpHost	IP	any, e.g 94.130.20.37	[not set]
Plain UDP Port	UdpPort	Number	any, e.g 3333	[not set]

Detailed Description

Host Parameter

Lobaro Platform CoAP

Hostname or IP of the Lobaro Platform instance CoAP endpoint to which the gateway communicates using UDP.

• Using DTLS: coaps://platform.lobaro.com
• No DTLS: coap://platform.lobaro.com
• Plain IP: 94.130.20.37 (platform.lobaro.com)

Host with fallback

It's also possible to configure a list of URLs to implement a fallback mechanism. This is particulary helpful for combining DTLS and non DTLS connection attempts: coaps://platform.lobaro.com,coap://platform.lobaro.com

MQTT

The device can communicate directly via MQTT. See MQTT → Host Parameter.

---

LTE Parameters

Parameters: APN Operator Band, PIN

Basic parameters are required to configure the NB-IoT or LTE-M connection. These settings must align with the SIM card and network provider used. Typically, the default parameters work well, as they enable the modem to automatically select and join the network using SIM card information. However, if the APN (Access Point Name) is known, it is recommended to configure it for optimal performance.

More Details

Read more about LTE network configuration parameters.

---

UseNbiot UseLtem

The modem supports both NB-IoT and LTE-M technologies. By default, both are enabled, allowing the cellular modem to automatically select the most suitable network type based on the location. However, you can force the modem to use a specific technology by setting one parameter to false, ensuring the other remains enabled (set to true). At least one technology must always be active.

---

UdpHost UdpPort

Deprecated

This feature is deprecated and not recommended for production use. Lobaro provides limited support for errors caused by using raw UDP upload.

Instead of sending metering data to the Lobaro IoT Platform, the data can alternatively be sent to an external UDP socket. This option is useful if you prefer to keep metering data off external servers while still using the Lobaro Platform to control your gateways.

• UdpHost: IP address to upload plain telegrams via UDP.
• [not set]: Defaults to uploading data to the Lobaro IoT Platform using the configured Host parameter.
• UdpPort: Port number to upload plain telegrams via UDP.
• Only used if UdpHost is set.

info

Even when metering data is sent to an external server, the firmware typically still requires a connection to a Lobaro Platform instance to send status information, perform remote configurations, or handle firmware updates.

For solutions that allow all communication without the Lobaro Platform, such as direct MQTT to an external broker, contact Lobaro for potential options.

LoRaWAN Connection

Description	Key	Type	Possible Values	Default
DevEUI	DevEUI	byte[8]	any	Device EUI64
AppEUI / JoinEUI (1.1)	AppEUI/JoinEUI	byte[8]	any	random
AppKey	AppKey	byte[16]	any	random
NwkKey (1.1)	NwkKey	byte[16]	any	00000000000000000000000000000000
Days between Timesync	TimeSync	Number	any	3
Payload Format	PayloadFormat	Number	0, 1, 2	0
Use OTAA	OTAA	Bool	true or false	true
Random TX Delay [s]	RndDelay	Number	any	10
Spreading Factor	SF	Number	7-12	12
Transmission Power	TxPower	Number	2-14	14
Adaptiv Data Rate	ADR	Bool	true or false	true
LoRaWAN max. Payload Length	loraPLMax	Number	10 to 241	100

Detailed Description

LoRaWAN 1.1

LoRaWAN 1.1 is experimental and not certified. For production environments, we recommend using LoRaWAN 1.0.2.

note

Depending on configuration some parameters are not available.

NwkKey Parameter

The Network Key (NwkKey) is used for LoRaWAN 1.1. If set to zeros (00000000000000000000000000000000) or to the same value as the AppKey, the device will stick to LoRaWAN 1.0.2 which is the recommended mode of operation.

PayloadFormat Parameter

Used encoding of the wmBus LoRaWAN uplink payload packets.

• 0 = Encoding in ports with static message length
• 1 = prefix bytes and time
• 2 = prefix bytes, time, and rssi

More Details

For a detailed specification of the payload formats, please refer to the LoRaWAN Communication page.

Special

Description	Key	Type	Possible Values	Default
Verbose UART Log	verbose	Bool	true or false	false
Addon RAM configuration	extRam	String	Lobaro Internal	[not set]
Live Mode	liveMode	String		[not set]
Operation Mode	opMode	Number	Lobaro Internal	1

Detailed Description

liveMode Parameter

An empty string disables the live mode. suppression=<seconds> enable live mode with suppression of duplicate telegrams for seconds

Analog Channel Parameters

Description	Key	Type	Possible Values	Default
Enable measurement on 4–20 mA input channel 1 (CH1)	ch1Enable	Bool	true / false false = channel disabled	true
Number of seconds to wait for the CH1 sensor to get ready after power on	ch1PreReadSec	Number	Seconds (integer) 0…	1
Number samples to take for a single CH1 measurement	ch1Samples	Number	1-1000	200
Scaling factor applied to the raw CH1 value	ch1Factor	Number	Numeric (float) e.g. 1.0, 0.1	1
Offset added to the CH1 value after scaling	ch1Offset	Number	Numeric (float) e.g. 0, -5.0	0
High alarm threshold for CH1 measurement value	ch1AlarmHigh	Number	Numeric (float) empty = disabled	[not set]
Low alarm threshold for CH1 measurement value	ch1AlarmLow	Number	Numeric (float) empty = disabled	[not set]
Enable measurement on 4–20 mA input channel 2 (CH2)	ch2Enable	Bool	true / false false = channel disabled	true
Number of seconds to wait for the CH2 sensor to get ready after power-on	ch2PreReadSec	Number	Seconds (integer) 0…	1
Number of samples taken for a single CH2 measurement	ch2Samples	Number	1-1000	200
Scaling factor applied to the raw CH2 value	ch2Factor	Number	Numeric (float)	1
Offset added to the CH2 value after scaling	ch2Offset	Number	Numeric (float)	0
High alarm threshold for CH2 measurement value	ch2AlarmHigh	Number	Numeric (float) empty = disabled	[not set]
Low alarm threshold for CH2 measurement value	ch2AlarmLow	Number	Numeric (float) empty = disabled	[not set]
Cron schedule used while an alarm is active, overriding the normal device cron	alarmCron	String	Cron expression (string) empty = no override	[not set]
Number of seconds CH1 stays powered after first power-on or brownout	ch1PwrAfterBrownoutDur	Integer	Seconds (integer) 0 = disabled	0

Detailed Description

chXFactor and chXOffset Parameters

The measured raw value is multiplied by chXFactor and then chXOffset is added. All further calculations and alarm checks are done with this derived value.

---

chXAlarmLow and chXAlarmHigh Parameters

If the calculated measurement value is above chXAlarmHigh or below chXAlarmLow, an alarm is triggered. The number of triggered alarms and the time in the alarm state is measured and transmitted.

---

alarmCron Parameter

In case of an active alarm, this cron is used instead of the regular cron. If empty, the regular sensor cron will be used.

OneWire Multi-Temperature Sensor Reading

Description	Key	Type	Possible Values	Default
Number of readouts to be uploaded together (saves energy)	MTempAcc	Number	1-600	1
List of sensor IDs or * for scanning	MTempIDs	String		*
Include Sensor ID in upload (LoRaWAN)	MTempSendID	Bool	true or false	false

Detailed Description

MTempAcc Parameter

The MTempAcc parameter specifies the number of readouts before the data is uploaded. When set to 1 the data is uploaded immediately. The data may be uploaded earlier if not enough free memory is available to store the measurements.

MTempIDs Parameter

The MTempIDs parameter specifies a list of sensor IDs separated by a ,. If the string it empty, all sensor readings are disabled. If a * is specified, a scan will be executed at boot and all new sensors added to the list.

Sensor ID

A complete sensor ID consists of 8 bytes:

byte    0: family code
bytes 1-6: serial number
byte    7: crc cecksum 

In data transmittions only the serial number is used by the device, family code and checksum are omitted for uploads. In configurations the full ID is used.

MTempSendID Parameter

If MTempSendID is set to true, the Sensor-ID is included in LoRaWAN transmissions. If set to false only the temperature values are transmitted.

Upload Formats LoRaWAN

note

Communication with this gateway version via LoRaWAN is currently not possible.

Upload Formats LTE

CoAP Protocol

The protocol details of the CoAP implementation are not publicly disclosed and are intended for use exclusively with the Lobaro IoT Platform. For integration with third-party systems, MQTT is the preferred protocol.

If you require access to this and MQTT is not an option, please contact Lobaro directly.

MQTT Protocol

MQTT Downlink Payload Size Limit

The maximum supported MQTT downlink payload size is approximately 4096 bytes (4 KiB). This includes the complete MQTT message payload (e.g. JSON configuration objects). Messages exceeding this size may result in configuration rejection.

Note: The effective usable payload size may be slightly lower due to protocol overhead.

Practical Implication

Large configuration objects (e.g. long device whitelists) must remain below this limit. Example: A comma-separated list of ~440 device IDs typically reaches the upper boundary.

Example JS Parser

A production-ready parser (including split telegram reassembly where applicable, AES-128 decryption for encrypted wM-Bus telegrams, and OMS-compliant data interpretation) is implemented within the Lobaro Platform.

Customers using the Lobaro Platform can utilize this parser directly as part of the platform processing pipeline.

If you are operating a Lobaro Gateway without using the Lobaro Platform, we can provide restricted platform access upon request. This allows you to inspect the parser behavior and use it as a technical reference for your own backend implementation.

Please contact our support team if you require access or further integration details.

Declaration of Conformity

Download CE declaration of conformity