⚡ ModBus (unofficial) Espressif support for power meters

This repo details how to use a Saola-1 ESP32S2 board coupled with a RS485 transceiver from LinkSprite and connect it to Espressif's IoT cloud platform: RainMaker.

Also, there's support for PVoutput.org graphs since my meter is coupled to three 500W solar panels (one per phase) equipped with APC microinverters.

There are several branches, all of them with custom setups that work with PlatformIO IDE with varying degrees of success:

🎋 Branches

master: FreeModbus from ESP-IDF framework with PVoutput.org and RainMaker support.
emodbus: eModbus with Arduino, first time I got the Modbus holding registers listed thanks to this eModbus discussion thread.
arduino-rainmaker: Same as emodbus, but trying to mix in RainMaker, ultimately switching to ESP-IDF (on master) after realising that Arduino support for RainMaker has some rough edges at the time of writing this.

The hardware setup is very similar to this eModbus hardware example thread with a couple of notable differences:

Here's a picture at some of the hardware specs from the power meter:

Don't forget to clone it like this, otherwise the RainMaker submodules will not be pulled and the code will not compile:

git clone --recursive
https://github.com/brainstorm/esp-modbus-power-meter/

The protocol used on top of RS485 is Modbus-RTU with 8N1 parity and with this code is acting as a master and the power meter as master.

app_modbus.c: ModBus RTU code
include/cid_tables.h: Definitions of the Modbus registers for the several power meters supported
app_rmaker.c: RainMaker setup for parameters and updates.
app_time.c: PVoutput.org time and date formatting for watts submission.
app_rgbled.c: Nothing to see here, move along XD
platformio.ini: Embeeded certs for RainMaker and other flashing/building goodies.

As usual with esp-idf, you should consult the official ESP-IDF docs as the following is tailored to my personal dev environment and paths:

conda activate esp
. $HOME/esp/esp-idf/export.sh
idf.py menuconfig build flash monitor

Make sure that menuconfig has those enabled as sometimes the build system forgets:

To re-provision RainMaker you'd need to kill the device's memory entirely and start over on your phone with:

idf.py erase-flash

So this is just a self-reminder, YMMV wildly ;)

Review your own power meter's manual and find the register(s) listing.
Submit a pullrequest with a CID table for your meter (see include/cid_tables.h)
Small and sweet code reviews and pull requests.

There are a few vague, vestigial references online about this power meter:

There's a youtube video showing the default setup password and some basic usage/configuration as well as a full [teardown video][yigedianqi_teardown]
A possible company spinoff, from yiGedianqi to yiHedianqi?
Several Amazon customers rating this meter and pointing out that it only comes with a chinese manual (true story).
A similar project, including Grafana, RPi and other power meters supported.