SHELLY Pro Modbus Add-on RS485 expansion module

The SHELLY Pro Modbus Add-on is an RS485 expansion module for compatible Pro devices, enabling Modbus RTU communication. Designed for DIN-rail mounting, it allows relays and meters to be integrated directly into professional BMS, EMS, SCADA or PLC systems.

The module supports both Modbus Client and Server modes. In Client mode, it reads registers from external devices such as inverters or energy meters. In Server mode, it makes the connected device’s own data and status available to external systems. It attaches directly to the host device’s expansion port, so it does not require a separate power supply. Its half-duplex RS485 bus supports stable data communication with up to 32 nodes in electrical distribution cabinets.