3Wire RS2MQTT/RS2MQTT+ | 4G MQTT Gateway
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RS2MQTT / RS2MQTT+ Connect Field Devices to IoTWatt 4.0 Through 4G
3Wire RS2MQTT and RS2MQTT+ are industrial-grade 4G IoT gateways designed to connect serial and Ethernet-based field devices such as PLCs, power meters, sensors and controllers to cloud-based IoT platforms.
For IoTWatt 4.0 projects, RS2MQTT provides a practical cellular connectivity layer where LAN or WiFi is not available. It can poll Modbus RTU and DTL-645 data, convert selected parameters into JSON format, and transmit data using MQTT or HTTP POST over 2G / 4G GPRS / LTE networks.
Overview: Remote Field Data to Cloud Without Fixed Network
Industrial sites often need to collect data from power meters, PLCs, sensors and other field devices, but fixed network infrastructure may not be available at every location. This is common for remote pump rooms, substations, outdoor panels, branch sites, temporary monitoring points and multi-site energy monitoring projects.
RS2MQTT and RS2MQTT+ solve this by connecting field devices directly to IoT platforms through cellular networks. Data can be polled from connected devices and transmitted using MQTT or HTTP POST, allowing the same field data to support dashboards, alerts, reports, analytics and IoTWatt 4.0 digital energy audit workflows.
Key positioning
RS2MQTT is best positioned as an industrial 4G gateway for remote energy monitoring, multi-site IoT deployment, cellular Modbus data collection and IoTWatt 4.0 projects where LAN / WiFi is not practical.
How RS2MQTT Supports IoTWatt 4.0 Connectivity
IoTWatt 4.0 depends on reliable meter and equipment data. RS2MQTT enables remote sites and distributed assets to send data to the platform without requiring local LAN or WiFi infrastructure.
Model Selection
RS2MQTT
Designed for serial-based device connectivity using RS232 and RS485. Suitable for Modbus RTU meters, PLCs, controllers and sensors that communicate over serial protocols.
Best for: Remote serial meter data collection through 4G.
RS2MQTT+
Includes the serial communication features of RS2MQTT, plus an additional Ethernet port to support TCP/IP-based data polling.
Best for: Remote sites where both serial and Ethernet devices must be polled.
IoT Gateway Capabilities
2G / 4G Connectivity
Supports GPRS / LTE data transmission for cloud connectivity where fixed LAN or WiFi is not available.
MQTT Protocol
Transmits field data to MQTT brokers and IoT platforms for monitoring, analytics and dashboards.
HTTP POST
Sends collected data to cloud platforms through HTTP POST where MQTT is not used.
JSON Data Conversion
DTL-645 and Modbus RTU parameters can be polled and converted into JSON format.
Internal Cache Memory
Stores up to 800 data records to help reduce data loss during temporary cellular network disruption.
Watchdog Circuit
Dedicated watchdog circuit supports stable and continuous 4G connectivity operation.
Key Features
TDD-LTE, FDD-LTE and GSM
Supports three cellular modes for broad 2G / 4G network compatibility.
High Serial Baud Rate
Supports baud rates from 300 bps to 921600 bps with 5 to 8 data bits.
RS232 / RS485 Interface
Terminal block for RS485 and DB9 connector for RS232 serial devices.
Modbus RTU to Modbus TCP
Supports transparent serial transmission, Modbus RTU to Modbus TCP and MQTT protocol functions.
Up to 32 RS485 Slaves
Supports up to 32 slave devices connected on the RS485 bus, depending on site design.
Up to 200 Parameters
Can poll up to 200 parameters from connected serial devices for structured reporting.
AT Command Configuration
Supports serial port AT command configuration for device setup and control.
LED Indicators
Power / 4G, Link and Active LED indicators provide local status visibility.
Heartbeat and Keep Alive
Heartbeat and Keep Alive functions help maintain reliable communication.
Technical Highlights
| Parameter | RS2MQTT / RS2MQTT+ Specification |
|---|---|
| Product Type | Industrial-grade 4G IoT gateway |
| Models | RS2MQTT and RS2MQTT+ |
| RS2MQTT+ | Includes additional Ethernet port for TCP/IP-based data polling |
| Device Connection | Serial and Ethernet-based devices such as PLCs, meters and sensors |
| Cellular Modes | TDD-LTE, FDD-LTE and GSM |
| 4G CAT 1 Bands | FDD LTE: B1 / B3 / B5 / B8; TDD LTE: B34 / B38 / B39 / B40 / B41; GSM: B3 / B8 |
| Transmission Rate | LTE: 10 Mbps downlink / 5 Mbps uplink; GPRS: 85.6 Kbps downlink / 85.6 Kbps uplink |
| SIM Card | 3V and 1.8V, standard SIM |
| Antenna | 50Ω / SMA type |
| Serial Interface | RS485 terminal block and RS232 DB9 |
| Serial Baud Rate | 300 bps to 921600 bps |
| Data Bits | 5 bits to 8 bits |
| Parity | None, Odd, Even, Mark and Space |
| Protocols | MQTT and HTTP POST |
| Modbus Function | Serial transparent transmission and Modbus RTU to Modbus TCP |
| JSON Conversion | DTL-645 and Modbus RTU parameters can be polled and converted to JSON format |
| RS485 Slave Capacity | Up to 32 slaves on RS485 bus |
| Parameter Polling | Up to 200 parameters polled |
| Cache Memory | Stores up to 800 data records |
| Configuration | Serial port configuration and 3Wire Device Management Software |
| Power Supply | 9VDC to 48VDC, DC jack |
| Power Requirement | 9-24V DC, 80mA @ 12V, 40mA @ 24V |
| Wiring | Plug-in screw terminal, accepts AWG12 to AWG30 wires |
| Operating Temperature | -40°C to +85°C |
| Storage Temperature | -45°C to +125°C |
| Humidity | 5% to 95% RH |
| Dimensions | 94mm (L) x 65mm (W) x 25mm (H) |
Network deployment note
For cellular deployments, confirm SIM plan, APN settings, signal strength, antenna placement, data usage, MQTT / HTTP endpoint details and fallback behaviour before installation.
Typical Applications
IoTWatt 4.0 Remote Metering
Send remote Modbus meter data to IoTWatt 4.0 for dashboards, analytics and digital energy audit reports.
Multi-Site Energy Monitoring
Deploy across branches, distributed assets, pump rooms, substations, retail outlets or remote facilities.
PLC and Sensor Data
Send data from PLCs, meters and sensors to MQTT brokers, IoT cloud systems or monitoring dashboards.
Industrial IoT Retrofit
Enable cloud connectivity where existing serial devices need to be connected without major wiring changes.
Remote Utility Monitoring
Collect data from water, gas, power or process meters in locations without local network infrastructure.
Temporary Monitoring
Useful for temporary metering points where a permanent LAN / WiFi network is not available.
Integration with IoTWatt 4.0
RS2MQTT is useful in IoTWatt 4.0 Digital Energy Audit and Energy Intelligence projects where power meters or sensors are located at remote panels, branch sites or areas without reliable LAN / WiFi connectivity. It enables cellular data collection directly from the field.
| IoTWatt 4.0 Use | How RS2MQTT Supports It |
|---|---|
| Remote Energy Dashboard | Publishes meter data through 4G to support IoTWatt 4.0 dashboards and site visibility. |
| Digital Energy Audit | Provides access to load profile and equipment data for audit evidence and analytics. |
| EECA Reporting | Supports remote meter data collection for regulatory reporting workflows. |
| Multi-Site Monitoring | Allows many sites to send structured data to a central IoTWatt 4.0 platform. |
| Data Continuity | Internal cache memory stores up to 800 records during temporary network disruption. |
IoTWatt 4.0 call to action
Use RS2MQTT when energy data needs to be collected from remote panels, distributed assets or branch sites where LAN / WiFi is not available, but IoTWatt 4.0 dashboards, EECA reports and energy audit evidence are required.
Recommended Deployment Checklist
- Confirm field device interface: RS232, RS485 or Ethernet for RS2MQTT+.
- Confirm protocol type: Modbus RTU, DTL-645, Modbus TCP or transparent serial.
- Confirm baud rate, parity, data bits, stop bits and slave address list.
- Confirm SIM card type, APN, data plan and 2G / 4G network coverage.
- Confirm antenna position and cellular signal strength at the installed panel.
- Confirm MQTT broker or HTTP endpoint, topic structure, payload format and polling interval.
- Confirm number of parameters to be polled and cache memory behaviour during network outage.
- Test end-to-end communication before handover to IoTWatt 4.0 or the host platform.
Related Keywords
RS2MQTT Operation Diagram
The diagram below shows the RS2MQTT / RS2MQTT+ 4G IoT gateway operation concept, including field device polling, MQTT / HTTP transmission and cloud platform connectivity.
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RS2MQTT / RS2MQTT+ industrial 4G IoT gateway operation diagram
RS2MQTT Supply, Setup and IoTWatt 4.0 Integration
Saturn Pyro supports 3Wire RS2MQTT and RS2MQTT+ gateways for 4G remote meter communication, MQTT / HTTP publishing, RS485 / RS232 integration, Modbus data collection, IoTWatt 4.0 digital energy audit projects, EECA reporting data collection and multi-site energy monitoring in Malaysia.
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