Product Description

Status: DRAFT

Product name

EMS Gateway

Purpose

The EMS Gateway provides local telemetry and control between supported photovoltaic / energy-storage inverters and the EMS backend platform.

The gateway reads operational data from the inverter and applies predefined control operations such as schedule changes and operating-mode changes.

Hardware baseline

• Raspberry Pi Zero W
• RS485 HAT
• microSD storage
• external power supply
• dedicated enclosure

Interfaces

• Wi-Fi
• RS485 / Modbus RTU
• local maintenance interface where enabled

Software baseline

• custom Raspberry Pi Linux image
• EMS Supervisor
• NATS client
• inverter-specific Modbus drivers
• VPN client

Backend connectivity

The gateway initiates outbound connections to backend services.

Current controls:

• VPN connectivity
• NATS JWT-based authentication/authorization
• backend device registration
• device association with customer e-mail and Raspberry Pi serial number

Security assumptions

• the customer LAN is not trusted
• the inverter Modbus interface is not authenticated and must be treated as a legacy local interface
• physical access to the gateway is possible and must be included in the threat model
• cloud commands must be validated by the gateway before any Modbus write

Product variants

TODO: document all hardware revisions, Wi-Fi variants, enclosure revisions and supported inverter families.