Integrating Fieldbus and Data-Centric Middleware: An STM32 Modbus Master Gateway for DDS-Based IIoT Systems

This paper presents an embedded gateway architecture that enables the seamless integration of Modbus-based industrial devices into Data Distribution Service (DDS) middleware for Industrial Internet of Things (IIoT) applications. The gateway, implemented on an STM32 microcontroller, acts as both a Modbus master and DDS-XRCE client, mapping Modbus registers directly to DDS topics with a configurable Quality of Service (QoS). Experimental validation demonstrates median latencies below 15 ms in four out of five scenarios, a throughput of up to 80 messages/s, and stable scalability to 160 subscribers with moderate resource usage. The results confirmed the feasibility and efficiency of Modbus–DDS integration on resource-constrained platforms.