The Fronius Smart Meter TS 65A-3 is a DIN-rail mounted 3-phase bidirectional energy meter designed for Fronius solar PV systems. The meter communicates via Modbus RTU over RS-485 to a Fronius inverter (or Datamanager 2.0), which then exposes the meter data via Modbus TCP on port 502. TapHome connects to the inverter’s Datamanager IP address — not directly to the meter. The TapHome template provides 2 electricity meter devices for bidirectional energy monitoring: Import Energy (From Grid) and Export Energy (To Grid), using SunSpec float model 211/212/213 registers.
The meter supports direct current measurement up to 65 A (no external CTs required) and operates in three wiring configurations: 3-phase 4-wire (3P4W), 3-phase 3-wire (3P3W), and 2-phase 3-wire (2P3W). All register values are IEEE 754 Float32, read via SunSpec float models through the Fronius Datamanager’s Modbus TCP gateway.
Hardware connection
RS-485 wiring (meter to inverter)
The Fronius Smart Meter TS connects to the Fronius inverter via a 3-wire RS-485 interface. Use a CAT5 or higher cable:
- M+ (Smart Meter) to D+ on Fronius inverter Modbus interface
- M- (Smart Meter) to D- on Fronius inverter Modbus interface
- GND (Smart Meter) to - on Fronius inverter Modbus interface
The Smart Meter has a built-in 120 ohm termination resistor. Activate it by placing a wire jumper between the M- and T terminals on the meter. This must be set on the last device in the RS-485 chain. Maximum cable length is 300 m.
Network connection (inverter to TapHome)
The Fronius inverter (or Datamanager 2.0) must be connected to the same network as TapHome via Ethernet. TapHome communicates with the inverter’s IP address over Modbus TCP on port 502.
| |
Configuration
Enabling Modbus TCP on the Fronius Datamanager
- Open the Fronius Datamanager web interface in a browser (use the inverter’s IP address)
- Navigate to Settings > Modbus
- Set the Modbus interface to tcp
- Ensure the SunSpec Model Type is set to float (models 211/212/213 — required by the TapHome template)
- Save the settings
Meter configuration
The meter’s default settings are compatible with the TapHome template. Verify the following on the meter’s display:
| Parameter | Code | Required Value | Default |
|---|---|---|---|
| System type | P3 | 3Pn (3-phase 4-wire) | 3Pn |
| Measurement mode | P6 | B (bidirectional) | B |
| Modbus address | P14 | 1 (primary meter) | 1 |
| Baud rate | P15 | 9.6 kbit/s | 9.6 |
| Parity | P16 | No | No |
The Modbus address on the meter itself (P14, default 1) is the RS-485 bus address between the meter and inverter. The Modbus TCP slave ID that TapHome uses (default 240) is configured in the Fronius Datamanager and refers to the meter data endpoint. These are two different addresses — do not confuse them.
To change meter parameters, press and hold Enter for 2 seconds, navigate to P1, enter password 2633, then navigate to the desired parameter.
Multi-meter setup
The Fronius system supports up to 4 meters: one primary meter (address 1) and up to 3 secondary meters (addresses 2-14). Each meter must have a unique Modbus address. The primary meter is always at address 1.
TapHome import parameters
After importing the template into TapHome, verify the module connection settings:
| Parameter | Value |
|---|---|
| IP Address | Fronius Datamanager IP (e.g. 192.168.1.x) |
| TCP Port | 502 |
| Slave ID | 240 |
Device capabilities
The template creates 2 ModbusElectricityMeter devices for bidirectional energy monitoring. Both devices read the same total AC power register (H:40097, W) but interpret the sign differently to separate import from export. The module also includes 5 service attributes providing device identification from the SunSpec Common Block.
Import Energy (From Grid)
Tracks energy consumed from the grid:
- Total consumption — cumulative imported energy (H:40137, TotWhImp, Wh divided by 1000 to kWh)
- Power demand — real-time import power (H:40097, W divided by 1000 to kW). Positive values indicate grid consumption.
Export Energy (To Grid)
Tracks energy fed into the grid from the solar PV system:
- Total consumption — cumulative exported energy (H:40129, TotWhExp, Wh divided by 1000 to kWh)
- Power demand — real-time export power (H:40097, W divided by -1000 to kW). The division by negative 1000 converts negative watt readings (grid feed-in) to positive kW values.
The import/export split uses the sign of the AC power register (H:40097). Positive watts indicate grid consumption (import), negative watts indicate grid feed-in (export). This is the standard SunSpec sign convention for meters at the grid connection point. Ensure measurement mode B (bidirectional) is enabled on the meter (parameter P6) for proper separate import/export energy counters.
Module service attributes
The module exposes 5 identification attributes from the SunSpec Common Block:
- Manufacturer — meter manufacturer string (H:40004, String32)
- Device model — meter model name (H:40020, String32)
- Options — device options string (H:40036, String16)
- SW version of meter — meter firmware version (H:40044, String16)
- Serial number of the meter — meter serial number (H:40052, String32)
Additional capabilities
The SunSpec float model 213 exposes additional registers not currently used by the TapHome template, including per-phase currents, per-phase voltages (phase-to-neutral and phase-to-phase), AC frequency, per-phase power (real, apparent, reactive), per-phase power factor, per-phase energy counters (import/export), and apparent energy accumulators. These can be added in a future template update.
Troubleshooting
No communication
- Verify that Modbus TCP is enabled on the Fronius Datamanager (Settings > Modbus > tcp)
- Confirm the SunSpec Model Type is set to float in the Datamanager — the TapHome template requires float models (211/212/213), not integer+scale factor models (201/202/203)
- Check that TapHome is using the correct IP address of the Fronius Datamanager/inverter, not the meter itself
- Verify the Slave ID is 240 in the TapHome module settings
- Ensure the RS-485 cable between the meter and inverter is properly connected (M+ to D+, M- to D-, GND to -)
- Check the RS-485 termination — activate the built-in termination on the last device by jumpering M- and T
Incorrect readings
- Confirm the measurement mode is set to B (bidirectional) on the meter (parameter P6) — mode A does not separate import/export energy
- If power readings are always zero, verify the meter’s system type (P3) matches the actual wiring — 3Pn for 3-phase 4-wire, 3P for 3-phase 3-wire
- If export power shows negative values, the template is working correctly — the division by -1000 in the export device converts negative watts to positive kW
Communication timeouts
Fronius recommends a minimum of 10 seconds between Modbus queries. If you experience timeouts, ensure no other Modbus TCP clients (such as Home Assistant or solar monitoring tools) are polling the Datamanager simultaneously. Only sequential queries are supported — parallel requests may cause communication failures.
