HD67C03-5-B2 – Industrial RS485 to MQTT Broker Converter in Housing Type B

HD67C03-5-B2 Converter – RS485 to MQTT Broker with Housing Type B and Screw Terminals.

The HD67C03-5-B2 is an industrial communication converter designed to integrate devices operating on RS485 with IoT and IIoT platforms using the MQTT Broker protocol. This model belongs to the HD67C03 family, known for its reliable and efficient conversion between serial communication and network-based MQTT structures. The 5-B2 version features a durable Housing Type B, screw-type terminal connectors and DIN rail mounting, making it ideal for industrial control cabinets and automation environments.

Engineered for harsh environments, the device supports a wide operating temperature range from -40°C to +85°C, offers high electrical robustness and is powered by 8…24 V AC or 12…35 V DC. These specifications correspond directly to the technical documentation and product datasheet .

The HD67C03-5-B2 supports RS485 serial communication, allowing integration with systems and devices using Modbus RTU, sensors, controllers, meters and other automation hardware with differential serial interfaces. On the network side, the device acts as a full MQTT Broker, meaning multiple MQTT clients, sensors, edge devices and software platforms can connect directly to it for structured data exchange.

RS485 to MQTT Broker – modern integration of serial devices with IoT

Converting from RS485 to MQTT Broker allows seamless integration of industrial serial devices into modern IoT platforms, cloud solutions, analytical systems and SCADA/BMS environments. The converter ensures data consistency, structured messaging and real-time communication between low-level serial networks and higher-level IT/OT systems.

• RS485 communication using screw terminals,
• differential signaling for long-distance communication,
• optional line termination using a DIP switch (as described in the manual),
• mapping serial data into MQTT topics,
• full MQTT Broker functionality with topic publishing/subscription,
• support for multiple concurrent MQTT clients.

RS485 supports multi-drop installations, enabling multiple devices to share a single bus while using the HD67C03-5-B2 as the gateway to MQTT-connected systems.

MQTT Broker – a local industrial data hub for IIoT systems

The HD67C03-5-B2 is not just a converter; it operates as a full MQTT Broker, enabling it to function as a central data exchange node for industrial automation, building automation or telemetry networks.

Multiple clients and devices can connect simultaneously, including:

• IoT sensors and field devices,
• edge gateways and controllers,
• HMI panels,
• cloud platforms and analytics tools,
• production management systems,
• data loggers and monitoring applications.

This makes the HD67C03-5-B2 a capable industrial data broker, bridging traditional serial infrastructure with modern network-based analytics and control systems.

Configuration using SW67C03 software and integrated webserver

Configuration of the device is performed using the dedicated SW67C03 software tool. The software can be downloaded here:
DOWNLOAD

Key configuration functions include:

• RS485 communication settings,
• defining MQTT Broker parameters,
• creating and managing MQTT client lists,
• data structure mapping into MQTT topics,
• routing topic structures,
• firmware update and diagnostic functions.

The converter also includes an integrated webserver, enabling device status monitoring, diagnostics and access to key operational parameters through a web browser.

Industrial construction – Housing Type B, screw terminals and DIN rail mounting

According to the datasheet and technical documentation, the HD67C03-5-B2 features:

• Housing Type B (Modulbox 4M),
• DIN rail 35 mm mounting,
• Dimensions: 70 × 60 × 95 mm,
• Weight: approx. 200 g,
• Screw-type terminals for RS485, power supply and signal interfaces.

Its robust enclosure, excellent temperature tolerance and galvanic isolation make it suitable for demanding industrial applications requiring long-term stability and operational safety.

Technical specifications

• Ports: RS485, Ethernet
• RS485 protocol: differential bus, DIP line termination
• MQTT Broker: full support for publish/subscribe
• Connectors: screw terminals (3-pin and 2-pin)
• Data rates: RS485 up to 115200 bps; MQTT 10/100 Base-T Autosensing
• Power supply: 8…24 V AC or 12…35 V DC
• Operating temperature: -40°C…+85°C
• Dimensions: 70 × 60 × 95 mm
• Weight: approx. 200 g
• Software: SW67C03
• Order code: HD67C03-5-B2

If you need assistance selecting the right RS485/MQTT Broker converter or verifying compatibility with your industrial system, our engineering team is ready to support you.