Hello All,
I have sum up below the information for this post:
Goal:
I want to control the two programmable relays (Relay 0 and the Open Collector K1) directly from Node-RED flows, without using VEConfig assistants.
Setup:
- EasySolar II 48/3000/35-32
- Venus OS 3.73 (integrated, no external Cerbo GX)
- Pylontech battery
- SmartSolar MPPT 250/70
- Node-RED via VRM Portal
What I have already done:
- Removed the “Programmable Relay” assistants from VEConfig to free up relay control
- Verified that relays work correctly when controlled via VEConfig assistants
- Confirmed Modbus TCP is enabled in Venus OS settings
What I have tried:
-
dbus via Node-RED exec node:
Scanned all services for relay paths. The path /Relay/0/State does not exist on com.victronenergy.vebus.ttyS3 or com.victronenergy.system.
Only relay-related paths found on vebus are internal protection relays (GridRelayReport, RelayTest, etc.).
The path /Settings/Relay/0/InitialState exists on com.victronenergy.settings and is writable, but does not control the relay in real time. -
Modbus TCP:
Tested all Unit IDs listed in Venus OS (100, 225, 228, 229, 230).
Only Unit ID 225 (Pylontech battery) responds correctly.
All other Unit IDs, including 228 (VE.Bus/MultiPlus), return: GatewayPathUnavailable (Exception 10).
Tested with both node-red-contrib-modbus and pymodbus directly. -
Custom Control node in Node-RED:
The MultiPlus-II appears in the device list, but no relay path is available in the Measurement dropdown.
Questions:
- Is there a working method to control Relay 0 and the Open Collector K1 from Node-RED on an EasySolar II with integrated Venus OS?
- Why does Modbus TCP return GatewayPathUnavailable for the VE.Bus Unit ID 228 on this integrated setup?
- Is there a specific dbus path for real-time relay state control on this device?
Any help or pointer to documentation would be greatly appreciated. Thank you!