dtu Gateway for Hoymiles HMS-800W-2T (2T series)

problem

The new series of Hoymiles inverter with internal wireless access point and wireless client have no direct API to include this endpoint in smarthome installations/ IFTT environments.

Usually there should be no need for an extra device to "translate" the connection to common APIs or bindings. Unfortunately the interface on the dtu is unlikely unstable/ or not really stable.

E.g. there is a treshhold of ~ 31 seconds before you can send new data to the dtu (e.g. new power limit), otherwise the connection hangs and an internal restart/ reboot (???) leads to an offline time of ~ 30 minutes. Data from dtu can be read in a very short time, but it has to be tested how often a request leads to the problem before.

On a manual way you can be back on track, if you are logging in to the local access point of the dtu and resend your local wifi login data to (it seems) initiate a reboot. With this way you can be back online in ~ 1:30 minutes.

So I decided to put this abstraction in an ESP8266 to have a stable abstraction to an existing smart home environment.

hint: the whole project could be also implemented on a small server and translated to e.g. python see here for an example and also the sources below

goal

Abstract the interface to the dtu (inverter connection endpoint) with different possibilities to connect to other systems. (push/ pull)
Very stable interface with no dependencies to an environment/ a system with a stand alone application based on an arduino board (ESP8266).
TODO: Ability to change running wifi to connect to dtu over local network or direct access point.
Use this need to create a full enivronment for an ESP8266 based project. (see features below)

features

regarding dtu

base connection to retrieve data from inverter e.g.
- power (Watts), voltage (V), current (A) for the PV input data (PV0,PV1) and the grid
- energy counter (kWh) for all 3 sources (day and total)
- temperature and wifi rssi of the dtu
setting the target inverter power limit dynamically
serving the readed data per /api/data
binding configuration with seperate activation and login data setting
binding: updating openHab instance with readed data and pulling set data from the instance
binding: updating to a MQTT broker with readed data [OPEN: pulling set power data from the mqtt instance]
for testing purposes the time between each request is adjustable (default 31 seconds)
syncing time of gateway with the local time of the dtu to prevent wrong restart counters
configurable 'cloud pause' - see experiences - to prevent missing updates by the dtu to the hoymiles cloud
automatic reboot of DTU, if there is an error detected (e.g. inplausible not changed values)
display SSH1106 implemented
- segmented in 3 parts
  - header:
    - left: wifi quality dtuGateway to local wifi
    - mid: current time of dtuGateway
    - right: wifi quality of dtu connection to local wifi
  - main:
    - small left: current power limit of inverter
    - big mid/ right: current power of inverter
  - footer:
    - left: current daily yield
    - right: current total yield
- additonal features
  - small screensaver to prevent burn-in effect with steady components on the screen (shifting the whole screen every minute with 1 pixel in a 4 step rotation)
  - smooth brightness control for changed main value - increase to max after change and then dimmming smooth back to the default level

regarding environment

serving own access point in factory mode for first setup
web application will be directly served by the system
settings of needed user data over the web app
- select found local wifi and enter/ save the needed wifi password
- change dtu connection data (e.g. host IP in local network, wireless user/ pass for dtu access point)
- configurable data for openhab item settings
OTA with direct connection to the github build pipeline - available updates will be checked by web app and device. Notification in web app, if update available and user can decide for direct online update

api

data - http://<ip_to_your_device>/api/data

{
  "localtime": 1704110892,
  "ntpStamp": 1707640484,
  "lastResponse": 1704063600,
  "dtuConnState": 1,
  "dtuErrorState": 0,
  "starttime": 1707593197,
  "inverter": {
    "pLim": 0,
    "pLimSet": 101,
    "temp": 0.00,
    "uptodate": 0
  },
  "grid": {
    "v": 0.00,
    "c": 0.00,
    "p": 0.00,
    "dE": 0.000,
    "tE": 0.000
  },
  "pv0": {
    "v": 0.00,
    "c": 0.00,
    "p": 0.00,
    "dE": 0.000,
    "tE": 0.000
  },
  "pv1": {
    "v": 0.00,
    "c": 0.00,
    "p": 0.00,
    "dE": 0.000,
    "tE": 0.000
  }
}

info - http://<ip_to_your_device>/api/info

{
  
  "chipid": 12345678,
  "host": "hoymilesGW_12345678",
  "initMode": 0,
  "firmware": {
    "version": "1.0.0022",
    "versiondate": "10.02.2024 - 19:23:57",
    "versionServer": "1.0.0051",
    "versiondateServer": "10.02.2024 - 19:23:57",
    "versionServerRelease": "checking",
    "versiondateServerRelease": "...",
    "selectedUpdateChannel": "0",
    "updateAvailable": 0
  },
  "dtuConnection": {
    "dtuHostIp": "192.168.0.249",
    "dtuSsid": "DTUBI-12345678",
    "dtuPassword": "dtubiPassword",
    "dtuRssi": 0,
    "dtuDataCycle": 32,
    "dtuResetRequested": 0,
    "dtuCloudPause": 1,
    "dtuCloudPauseTime": 40
  },
  "openHabConnection": {
    "ohHostIp": "192.168.1.100",
    "ohItemPrefix": "inverter"
  },
  "wifiConnection": {
    "networkCount": 2,
    "foundNetworks": [
      {
        "name": "Name1 Wlan",
        "wifi": 62,
        "rssi": -69,
        "chan": 1
      },
      {
        "name": "name2-wifi",
        "wifi": 48,
        "rssi": -76,
        "chan": 3
      }
    ],
    "wifiSsid": "myWifiSSID",
    "wifiPassword": "myPass",
    "rssiGW": 87
  }
}

openhab integration/ configuration

set the IP to your openhab instance - data will be read with http://<your_openhab_ip>:8080/rest/items//state
set the prefix () of your openhab items
list of items that should be available in your openhab config
- read your given power set value from openhab with "_PowerLimit_Set"
- set openhab items with data from dtu:
  - grid data:
    - "Grid_U"
    - "Grid_I"
    - "Grid_P"
    - "PV_E_day"
    - "PV_E_total"
  - panel 1 data:
    - "PV1_U"
    - "PV1_I"
    - "PV1_P"
    - "PV1_E_day"
    - "PV1_E_total"
  - panel 2 data:
    - "PV2_U"
    - "PV2_I"
    - "PV2_P"
    - "PV2_E_day"
    - "PV2_E_total"
  - inverter status:
    - "_Temp"
    - "_PowerLimit" //current read power limit from dtu
    - "_WifiRSSI"

mqqt integration/ configuration

set the IP to your MQTT broker
set the MQTT user and MQTT password
set the main topic e.g. 'dtu1' for the pubished data

data will be published as following ('dtu1' is configurable in the settings):

dtu1/timestamp

dtu1/grid/U
dtu1/grid/I
dtu1/grid/P
dtu1/grid/dailyEnergy
dtu1/grid/totalEnergy

dtu1/pv0/U
dtu1/pv0/I
dtu1/pv0/P
dtu1/pv0/dailyEnergy
dtu1/pv0/totalEnergy

dtu1/pv1/U
dtu1/pv1/I
dtu1/pv1/P
dtu1/pv1/dailyEnergy
dtu1/pv1/totalEnergy

dtu1/inverter/Temp
dtu1/inverter/PowerLimit
dtu1/inverter/WifiRSSI

known bugs

sometimes out-of-memory resets with instant reboots (rare after some hours or more often after some days)

releases

installation / update

hardware

ESP8266 based board

optional display:

connect SSH1106 driven OLED display (128x64 e.g. 1.27") with your ESP8266 board (VCC, GND, SCK, SCL)

pinning for different boards (display connector to ESPxx board pins)

dev board	ESP family	VCC	GND	SCK	SDA	tested
AZDelivery D1 Board NodeMCU ESP8266MOD-12F	ESP8266	3.3V	GND	D15/GPIO5/SCL/D3	D14/GPIO4/SDA/D4	OK
AZDelivery NodeMCU V2 WiFi Amica ESP8266 ESP-12F	ESP8266	3.3V	GND	D1/GPIO5/SCL	D2/GPIO4/SDA	OK
AZDelivery D1 Mini NodeMcu mit ESP8266-12F	ESP8266	3V3	G	D1/GPIO5/SCL	D2/GPIO4/SDA	OK

first installation to the ESP device

download the preferred release as binary (see below)
HAS TO BE VERIFIED [only once] flash the esp8266 board with the (esp download tool)[https://www.espressif.com/en/support/download/other-tools]
1. choose bin file at address 0x0
2. crystal frequency to 26 Mhz
3. SPI speed 40 MHz
4. SPI Mode QIO
5. Flash Size 32 MBit-C1
6. select your COM port and baudrate = 921600
7. press start ;-)
all further updates are done by OTA (see chapters above)

first setup with access point

connect with the AP hoymilesGW_ (on smartphone sometimes you have to accept the connection explicitly with the knowledge there is no internet connectivity)
open the website http://192.168.4.1 (or http://hoymilesGW.local) for the first configuration
choose your wifi
type in the wifi password - save
in webfrontend setting your DTU IP adress within your local network (currently the user and password for dtu are not needed, for later integration relevant for a direct connection to the dtu over their access point)
then you can configure your needed binding
1. openhab -> set the IP of your openhab instance and the prefix for the dtu items according to your configured item file in openhab
2. mqtt -> set the IP and port (e.g. 192.178.0.42:1883) of your mqtt broker and the user and passwort that your hacve for this instance
after this one time configuration the connection to the dtu should be established and the data displayed in the webfrontend and according to your setup transmitted to the target instance

return to factory mode

connect your ESP with serial (115200 baud) in a COM terminal
check if receive some debug data from the device
type in resetToFactory 1
response of the device will be reinitialize EEPROM data and reboot ...
after reboot the device starting again in AP mode for first setup

main

latest release - changes will documented by commit messages https://github.com/ohAnd/dtuGateway/releases/latest

(to be fair, the amount of downloads is the count of requests from the client to check for new firmware for the OTA update)

snapshot

snapshot with latest build https://github.com/ohAnd/dtuGateway/releases/tag/snapshot

experiences with the hoymiles HMS-800W-2T

set values - frequency

(not fully investigated yet)

If there to much requests of setting the power limit minutes later the connection is broken and cannot be directly established again - with current experience the dtu resets itself after ~ 30 min and is accessable again.

With the manual login to dtu access point and forcing the storing of local wifi connect data again, then dtu is back online and accessable in your local network. (This is a possible feature that can be implemented in future - needed protocol sequence has to be investigated)

[2024-03-24]

lot of single updates for power setting within few seconds (< 2-3) without any reading of values (e.g. realdata) -> it seems this creating no problems
therefore current setup -> no time limit for power setting, but reading data only every 31 seconds is running fine
sometimes hanging or full shutdown/ break of DTU will be prevented by sending an active reboot request to dtu (hanging detection at this time over grid voltage, should be changing at least within 10 consecutive incoming data)
with this setup: now the device is running for days without any stops (overall system point of view: target settings will be performed everytime, readed data will be available, no manual steps needed to recover the dtu connection)

hoymiles cloud update

everey 15 min (0,15,30,45) -> timestamp update
after 7 min 40 s update of graph data (if wifi not reachable, also reset of wifi AP)

sources

build environment

fully covered with github actions

building on push to develop and serving as a snapshot release with direct connection to the device - available updates will be locally checked and offered to the user for installation

hint: referring to Error Build in platform.io - buildnumber file not found #6 for local building:

For automatic versioning there is a file called ../include/buildnumber.txt expected. With the content "localDev" or versionnumber e.g. "1.0.0" in first line. (File is blocked by .gitignore for GitHub actions to run.)

platformio

https://docs.platformio.org/en/latest/core/installation/methods/installer-script.html#local-download-macos-linux-windows

hints for workflow

creating dev release (https://blog.derlin.ch/how-to-create-nightly-releases-with-github-actions)

Name		Name	Last commit message	Last commit date
Latest commit History 116 Commits
.github		.github
.vscode		.vscode
include		include
src		src
.gitignore		.gitignore
LICENSE		LICENSE
dtuConst.h		dtuConst.h
platformio.ini		platformio.ini
readme.md		readme.md
srcConverter.py		srcConverter.py
version_inc.py		version_inc.py

License

ohAnd/dtuGateway

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