This ESP8266 firmware enables you to read information from a Samil solar inverter through it's RS485 bus. Sending information to a MQTT broker is supported, as well as uploading information to PVoutput. This is a fork of https://github.com/jantenhove/GoodWeLogger
- Samil inverter with RS485 connector
- RS485 converter (can be found on sites like AliExpress, search for SCM TTL to RS485 Adapter 485 to UART Serial Port 3.3V 5V Level Converter Module)
- ESP8266 (like NodeMCU or Wemos D1 mini)
- Computer with Arduino IDE installed
- To flash this firmware, you will need to install the Arduino IDE and configure it for the board you are using (NodeMCU / Wemos)
- You will also need the following libraries
- 'Time' library
- NTPClient
- PubSubClient
Place these into the
librariesfolder belonging to Arduino on your system.
- Clone/download this repository
- Rename the
Settings.example.htoSettings.hand configure it to match your preferred settings - Compile and upload the firmware to your ESP8266
- Diagnostics information is sent over serial at 115200 baud (wifi status, MQTT status, inverter connection status)
The RS485 connector on the inverter is located at the bottom of the inverter. It is hidden behind a small metal plate. There will be two (2) RJ11, 4 pin sockets. Only one RJ11 (left) is required and the pinout is as follows (left to right):
| Pin | Function |
|---|---|
| 1 | TX+ |
| 2 | TX- |
| 3 | RX+ |
| 4 | RX- |
Connection from the TTL-RS485 module:
| TTL RS485 | Connection |
|---|---|
| A+ | TX+ and RX+ |
| B+ | TX- and RX- |
Other models might use a different method of connecting. Consult your inverter manual.
Connect the RS485 converter to your ESP8266 like this:
| RS485 converter | ESP8266 |
|---|---|
| GND | G / GND |
| RXD | D1 |
| TXD | D2 |
| VCC | 5V / 3V3 |
(D1 (receive) and D2 (transmit) can be configured to different pins in Settings.h). It might look weird to connect RXD of the module to the receive pin of the ESP8266, but this is how the RS485 converter is labeled.
Subscribe to the samil/ topic in your MQTT client. Information will be posted there and will look like this:
samil/93600DVA295R148/vpv1 242.6
samil/93600DVA295R148/vpv2 235.7
samil/93600DVA295R148/ipv1 4.9
samil/93600DVA295R148/ipv2 5.5
samil/93600DVA295R148/vac1 240.6
samil/93600DVA295R148/iac1 10.7
samil/93600DVA295R148/fac1 49.99
samil/93600DVA295R148/pac 2582
samil/93600DVA295R148/temp 38.6
samil/93600DVA295R148/eday 6.40
samil/93600DVA295R148/workmode 1
samil/93600DVA295R148/online 1
| Field | Description | Unit |
|---|---|---|
| vpv1 | Voltage of first string of solarpanels | V |
| vpv2 | Voltage of second string of solarpanels | V |
| ipv1 | Current of first string of solarpanels | A |
| ipv2 | Current of second string of solarpanels | A |
| vac1 | Voltage mains side inverter | V |
| iac1 | Current mains side inverter | A |
| fac1 | Frequency (Hz) mains side inverter | Hz |
| pac | Current power production in Watt | W |
| temp | Internal temperature of inverter | °C |
| eday | Energy produced today | kWh |
| workmode | Undocumented parameter. Default=1 | binary |
| online | Inverter status (1=on, 0=off) | binary |
When you have your PVoutput API key and System ID configured correctly in Settings.h, production data from the inverter will be uploaded to PVoutput every 5 minutes (interval is configurable in Settings.h, but don't go lower than the minimal interval of every 5 minutes as specified by PVoutput).
When multiple inverters are connected, by daisy-chaining the RS485 cable, only the production data of the first inverter will be uploaded.
For the PVoutput upload function to work, it is important that the ESP8266 has access to the internet. Apart from connections being made to PVoutput, you will also see that the ESP8266 talks with pool.ntp.org on a regular interval. This is done to retrieve the current time, which is needed to post data to PVoutput.
If you plan to use only MQTT, internet access for the ESP8266 is not needed.