Fronius GEN24
The power changed
Fronius GEN24 Modbus Control
Smarter Fronius GEN24 control over Modbus TCP.
Control Fronius GEN24 inverter and battery via Modbus TCP from Homey Pro.
Requirements
- Homey Pro (local apps)
- Fronius GEN24 with Modbus TCP enabled
- Optional: Fronius Smart Meter (needed for import/export based cards)
Inverter setup (web UI)
1) Communication -> Modbus
- Mode: TCP Server
- SunSpec Model Type: int + SF
- Port: 502
- Allow Control: ON
- Note Meter Address Offset (Smart Meter Unit ID, usually 200)
2) Grid Regulations / Export Limitation (optional)
- Set Maximum grid feed-in power in the inverter UI
- This is used by "Use inverter export limit"
3) Battery charging from grid (optional)
- Enable if you want grid charging
Add device in Homey
- Enter inverter IP/hostname, port and Unit ID (default 1)
- If you use a Smart Meter, set Smart Meter Unit ID (default 200)
Important settings in the app
- Installed PV/site capacity (Wp): total installed PV capacity in Wp (sum of all arrays)
Used by "Limit inverter production to X W"
- Battery max charge/discharge (kW) and optional battery capacity (kWh)
Used to convert W to percent for storage control
- Inverter max AC power (kW) fallback
Notes
- Import-capped charging and zero export run in a loop until stopped.
- Intervals are in seconds (min 30 s for import-capped charging).
- Modbus control can affect inverter and battery behavior. Use at your own risk.
Supported devices
Flow cards
Click on a device above to show related Flow cards only.
When...
Fronius GEN24
Export exceeds Threshold (W) W
Triggers when grid export exceeds the specified threshold.
Fronius GEN24
Import exceeds Threshold (W) W
Triggers when grid import exceeds the specified threshold.
Fronius GEN24
Limited charging started
Triggers when limited charging mode is activated.
Fronius GEN24
Limited charging stopped
Triggers when limited charging mode is deactivated.
Fronius GEN24
Peak shaving started
Triggers when peak shaving mode is activated.
Fronius GEN24
Peak shaving stopped
Triggers when peak shaving mode is deactivated.
Fronius GEN24
Auto zero export started
Triggers when auto zero export mode is activated.
Fronius GEN24
Auto zero export stopped
Triggers when auto zero export mode is deactivated.
And...
Fronius GEN24
Limited charging is active
Check if limited charging mode is currently running.
Fronius GEN24
Peak shaving is active
Check if peak shaving mode is currently running.
Fronius GEN24
Auto zero export is active
Check if auto zero export mode is currently running.
Then...
Fronius GEN24
Disable inverter export limit
Enables Modbus override: ramp=0, WMaxLimPct=100%, WMaxLim_Ena=1.
Fronius GEN24
Use inverter export limit
Disables Modbus override (WMaxLim_Ena=0) so the inverter's Grid Regulations/export limit setting controls export.
Fronius GEN24
Force discharge now with Discharge power (W) W
Forces battery discharge by writing negative rate. Uses device capacity/max kW + scale. Sets StorCtl_Mod=2.
Fronius GEN24
Reset battery control
Stops external control: zeros charge/discharge limits and sets StorCtl_Mod=0.
Fronius GEN24
Set min charging to Charge power (W) W
Ensures battery charges at this rate, pulling power from the grid if solar is insufficient. Example: Set to 3000 W but only 1000 W solar → battery charges at 3 kW (1 kW solar + 2 kW from grid).
Fronius GEN24
Discharge now with Discharge power (W) W
Sets battery max discharge limit (OutWRte). Uses device settings (capacity/max kW + scale). StorCtl_Mod is set to discharge.
Fronius GEN24
Set export limit to Max production (W) W
Limits grid export (feed-in) to this W target. Uses WMaxLimPct to cap how much power is sent to the grid. Same register as production limit but different use case.
Fronius GEN24
Set max charging to Max charge (W) W
Limits battery charging to this rate from solar only. Any excess solar power is exported to the grid instead of charging the battery. Example: Set to 1000 W and you have 3000 W solar → battery charges at 1 kW, 2 kW is exported.
Fronius GEN24
Start limited charging up to Max charge (W) W (max import Max grid import (W) W, fuse Main fuse per phase (A, optional) A/phase, interval Check interval (s, min 30) s)
Fronius GEN24
Keep import under Peak target (W) W (duration Duration (minutes, 0 = until stopped) min, interval Update interval (seconds) s)
Discharge to keep import below the peak target. Runs periodically until duration expires or stopped.
Fronius GEN24
Set production limit to Max production (W) W
Limits total inverter AC output (WMaxLimPct) to this W target as percentage of installed capacity. This caps how much the inverter produces regardless of house consumption.
Fronius GEN24
Start auto zero export (interval Update interval (seconds) s, duration Duration (minutes, 0 = until stopped) min)
Adjusts feed-in limit to keep export near 0 W using Smart Meter. Runs periodically until stopped or duration expires.
Fronius GEN24
Stop limited charging
Fronius GEN24
Stop peak shaving
Stops running peak shaving and resets discharge to 0.
Fronius GEN24
Remove production limit (restore 100%)
Fronius GEN24
Stop auto zero export
Stops running auto zero export and disables Modbus override.
Support
The developer of this app does not offer direct support.
What’s new
Version 1.3.28 — Smarter reconnection with exponential backoff (2s→60s). Better handling of stale connections after network outages.
Fronius GEN24 Modbus Control
Fronius GEN24 Modbus Control is not compatible with the selected Homey.
Fronius GEN24 Modbus Control will install on Homey shortly.
Changelog
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