AuroraMonbus is a Windows desktop application written in C# (.NET 8) that communicates directly with some Power-one Aurora / ABB / FIMER Aurora solar inverters over RS-485 (serial). It provides real-time monitoring, diagnostics, and system performance insights through a modern, responsive WinForms interface.
When I say some (inverters), I only have a Power-One Aurora PVI-3.0 OUTD invertor from around 2012 and I have not tested (and sorry dont plan to) on anything else.
I only built this tool for that unit with a view to eventually build in these capabilities:
- Publish MQTT messages in a format suitable for Home Assistant MQTT to consume.
- Send to the pvoutput.org API.
- Minimise to the Windows system tray.
But you can take this code and do what you like for yours / other models as a fair bit went into getting it this far and generally reliable.
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Direct Serial Communication Implements the Aurora protocol for two-way communication with inverters using CRC-16-CCITT framing and robust retry logic. Supports all core commands including real-time operating data, temperature, and energy counters.
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Real-Time Polling Continuously retrieves and displays inverter metrics such as:
- Grid voltage, current, power, and frequency
- PV input voltages/currents and derived wattage
- Inverter and booster temperatures
- Daily, monthly, yearly, and total energy generation
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Diagnostics Mode Toggle raw communication bytes ([TX] and [RX] traces) in real time for advanced debugging and protocol analysis.
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System Information Snapshot A single click shows firmware version, part number, and hardware-level inverter diagnostics via the System Info button.
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Configurable Runtime Settings Load communication parameters such as COM port, baud rate, inverter address, and polling interval directly from AppConfig.json — no recompilation required.
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Safe Multithreading Async-safe communication with full UI-thread marshaling for stable, non-blocking operation and graceful cancellation on disconnect.
| File | Purpose |
|---|---|
| MainForm.cs | WinForms front-end, handles UI updates, background polling, and status display |
| AuroraClient.cs | Communication layer implementing Aurora serial protocol, CRC handling, retries, and energy counter decoding |
| ByteArrayExtensions.cs | Utility methods for decoding inverter float and integer data (big-endian) |
| AppConfig.cs | Loads and manages configuration values from JSON |
| AppConfig.json | Runtime configuration for serial settings and polling interval |
- Implements Aurora protocol commands (0x3B, 0x4E, 0x34, 0x3A, etc.)
- Uses async/await for all I/O operations
- Built-in error recovery, port reopen logic, and CRC validation
- Debug output through System.Diagnostics.Debug.WriteLine()
- Clean disposal pattern with IDisposable and GC.SuppressFinalize
- Optimised polling interval with intelligent UI button toggling
- Connect your inverter RS-485 port to a RS485 to Ethernet Converter such as this https://www.pusr.com/products/1-port-rs485-to-ethernet-converters-usr-tcp232-304.html or similar Wi-Fi model (recommend) to get a virtual COM port in Windows or use a RS-485 to USB adapter.
- Configure your AppConfig.json
{ "ConnectionType": "Serial", "SerialPort": "COM4", "BaudRate": 19200, "Address": 2, "PollingInterval": 10000 } - Run the application, click Connect, and watch data stream live.
- Click System Info for inverter identity and firmware version.
- SerialPort is your Comport number.
- BaudRate is 19200 for serial comms on these units typically.
- Address will nearly always be 2.
- PollingInterval is in milliseconds. 10 seconds (as shown) is safe and generally about all your need. The protoocol and this software implementation could go as low as 5 seconds safely - YMMV.
- Fully async-safe and thread-isolated for WinForms.
- Ideal base for building on.