Fronius - Modbus TCP
Monitors Fronius Symo and Primo inverters via Modbus TCP
This ModbusCloud template reads AC and DC electrical data plus lifetime energy production from Fronius Symo and Primo solar inverters over Modbus TCP. Fifteen read-only registers cover per-phase AC voltage, current, power, frequency, and MPPT 1 and 2 DC voltage, current, and temperature. It is the standard float-based SunSpec template for Fronius installations.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 15, read only
- Brand
- Fronius
- Key readings
- AC Voltage Phase 1 to 3 · AC Current Phase 1 to 3 · AC Power · AC Frequency · DC Voltage and Current (MPPT 1 and 2) · Temperature MPPT 1 and 2
- Compatible models
- Symo · Primo
- Last updated
Registers (15)
15 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| AC Voltage Phase 1 | V | Read | |||
| AC Voltage Phase 3 | V | Read | |||
| AC Voltage Phase 2 | V | Read | |||
| AC Power | kW | Read | |||
| AC Frequency | Hz | Read | |||
| AC Current Phase 1 | A | Read | |||
| AC Current Phase 2 | A | Read | |||
| AC Current Phase 3 | A | Read | |||
| DC Voltage 1 | V | Read | |||
| DC Voltage 2 | V | Read | |||
| DC Current 1 | A | Read | |||
| DC Current 2 | A | Read | |||
| Temperature MPPT 1 | °C | Read | |||
| Temperature MPPT 2 | °C | Read | |||
| AC Lifetime Energy production | kWh | Read |
Loading registers…
Send your device list
If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Plot hourly PV yield curves per inverter to spot shading and soiling issues on customer rooftops.
- Create a monthly or yearly energy production report that is automatically emailed to the customer.
- Alert the installer when MPPT temperature exceeds a safe limit, a common early sign of a failing fan or bad ventilation.
- Track grid frequency and voltage excursions to help the customer challenge grid quality complaints with documented data.
Installation
In the Fronius web UI, navigate to Communication, enable Modbus TCP, and set SunSpec Model Type to float. Save and reboot the Datamanager if prompted.
Note the inverter IP address on your LAN. Set a DHCP reservation so the address does not change.
In ModbusCloud, add a new device with protocol Modbus TCP, port 502, slave ID 1, and the inverter IP.
Import the Fronius Modbus TCP template. Readings appear within a few polling cycles.
Things to watch for
The inverter is online but ModbusCloud shows timeouts. What to check?
Verify that Modbus TCP is actually enabled in the Fronius Datamanager web UI. The inverter responds to ping even when Modbus is off. Also confirm the SunSpec Model Type is float and not int+SF for this template.
AC power reads zero at night. Is the template broken?
That is correct behaviour. Fronius inverters shut down when there is no PV production, so all AC values drop to zero or report as not valid. Lifetime energy stays accurate because the Datamanager retains it.
Want to see how it works?
