Uni-Directional Modbus Serial/RS485/RTU to MQTT Converter in Node-RED with RAW Payload

Overview

This Node-RED flow provides a seamless, uni-directional communication bridge between Modbus Serial/RS485/RTU devices and an MQTT broker, enabling efficient data collection and transmission in raw payload format. Designed for scalability, it supports multiple Modbus devices and multiple register configurations, making it ideal for industrial automation, IoT, and smart infrastructure applications.

Demo & Tutorials

📺 Watch the Demo Video (https://youtu.be/qCjuy-NAde4)

Key Features

✅ Modbus RTU/RS485/Serial to MQTT Conversion – Reads data from Modbus devices (RTU/Serial/RS485) and publishes it to an any MQTT broker.
✅ RAW Payload Support – Transfers data in raw format, ensuring minimal processing overhead and compatibility with various MQTT consumers.
✅ Scalable Architecture – Easily expandable to support multiple Modbus devices and multiple register mappings without complex modifications.
✅ Flexible Configuration – Customizable polling intervals, register addresses, and MQTT topics for tailored integration.
✅ Lightweight & Efficient

Use Cases

• Industrial IoT (IIoT) – Collect sensor data from PLCs, energy meters, and industrial controllers.

• Smart Buildings – Monitor HVAC systems, lighting controls, and power meters via MQTT.

• Remote Monitoring – Transmit Modbus device data to cloud platforms or central dashboards.

• Legacy System Integration – Modernize old Modbus-based systems by connecting them to MQTT-enabled SCADA or analytics tools.

Technical Specifications

• Protocols Supported: Modbus RTU (Serial/RS485), MQTT

• Payload Format: RAW

• Deployment: Runs on Node-RED (Windows/Linux/Raspberry Pi/Docker/Edge Devices).

• Extensible: Supports adding multiple Modbus slaves and register blocks

Why Choose This Solution?

• Plug-and-Play Setup – Pre-configured flow for quick deployment.

• Open & Customizable – Modify as needed for specific Modbus device requirements.

• Reliable & Lightweight – Optimized for stable, long-term operation.

Ideal For

Automation engineers, IoT developers, and system integrators looking for a robust, scalable Modbus-to-MQTT gateway without proprietary software dependencies.