Development of a Protocol Converter from SMA Data to Modbus TCP for SCADA Integration

Abstract

The integration of distributed energy resources into smart microgrids frequently necessitates seamless communication between heterogeneous devices and centralized supervisory systems. However, specific power electronics equipment, such as the SMA Sunny Island inverter, relies on proprietary communication protocols that are incompatible with standard SCADA interfaces. The present work delineates the design and implementation of a protocol converter that facilitates transparent translation between SMA Data and Modbus TCP, thereby enabling native integration of the Sunny Island inverter into Modbus-based SCADA environments. The proposed converter was developed using a Raspberry Pi platform and employs a modular architecture that combines the YASDI communication library with a custom Python-based Modbus TCP server. The system retrieves operational data from the inverter, maps it to Modbus input registers, and allows configuration commands to be issued from the SCADA system and applied to the inverter in a controlled manner. The experimental validation was carried out in the Microgrid Laboratory at the University of Cuenca. In this setting, the converter demonstrated reliable performance in two specific tasks: data acquisition and parameter configuration. The response times exhibited a range of 10 to 30 seconds, contingent upon the system's state. Following power cycles and communication interruptions, the converter demonstrated complete recovery capability. The findings substantiate the viability of the proposed method as a cost-effective and resilient solution for integrating proprietary energy devices with industrial monitoring platforms. Its flexibility and resilience render it suitable for broader deployment in smart grid infrastructures and distributed energy management systems.