Introduction

The Vandyam VIoT RS-485 Node is an industrial-grade RS485-to-LoRaWAN interface built to bridge Modbus RTU devices with long-range, low-power wireless networks. It allows automation companies, system integrators, and industrial IoT teams to connect existing RS485/Modbus instruments — such as energy meters, water and flow meters, level transmitters, and other industrial sensors — directly to LoRaWAN infrastructure, eliminating the need for extensive rewiring or local data-collection hardware.

Acting as a full Modbus RTU master, the node can poll and cycle through up to 20 Modbus slave devices from a single unit, with per-slave polling intervals, configurable register counts, and flexible register-to-parameter mapping. Built-in CRC checking ensures data integrity on every read, while bi-directional communication supports both sensor-data uplinks and remote, MQTT-based configuration — so polling behavior and register maps can be updated without a site visit.

Designed for continuous outdoor and industrial deployment, the RS-485 Node is housed in a weatherproof enclosure, drawing as little as ~2μA in sleep and 30mA when active, powered from a 12V DC external supply. On the radio side, it operates on the IN865 MHz band with an external SMA antenna for extended range in challenging RF environments like factories, plants, and utility sites.

Key Features

• Full Modbus RTU master support over a native RS485 interface
• Multi-device support — connect up to 20 Modbus slaves per node
• Bi-directional communication for both uplink data and downlink configuration
• Dynamic, remote configuration via MQTT
• Multi-slave cycling that automatically polls across connected Modbus devices
• Intelligent parsing with configurable register mapping for different data types
• Flexible mapping of any Modbus register to any parameter name
• Configurable polling intervals and register counts per slave
• Modbus CRC checking to ensure data integrity
• Ultra-low sleep current (~2μA) with 30mA typical operating current

Applications

• Industrial automation — connecting PLCs, drives, and controllers to LoRaWAN
• Energy and utility metering — remote automated meter reading for energy, water, and gas meters
• Smart cities and smart campuses — wireless retrofits of legacy Modbus infrastructure
• Process and environmental monitoring — level, flow, and pressure transmitters
• Remote and off-grid asset monitoring where new wiring is impractical