Fronius Eco

Compatibility

Compatible with EpiSensor Edge over Modbus TCP or Modbus RTU

The Eco datasheet lists Modbus TCP SunSpec over Ethernet or WLAN and Modbus RTU SunSpec on RS485, both through the integrated Fronius Datamanager 2.0. Fronius publishes the Datamanager Modbus operating instructions and the SunSpec register maps. Edge reads the maps as a Modbus TCP or RTU client with FC03.

Fronius Eco 25.0-3-S and 27.0-3-S with a Fronius Datamanager 2.0 card, using operating instructions 42,0410,2049 edition 033-24022026 and the Fronius SunSpec map archive 1.1.7-0. The light version has no Datamanager and needs a Datamanager card before Edge can read it. Site check: confirm the SunSpec model type set on the Datamanager and compare the first AC power read with the inverter display.

Connect it with

• Modbus Interface ZMB-3X From €399 ex VAT Configure
• Gateway ZGW-20 From €899 ex VAT Configure
• Evaluation Gateway on a Raspberry Pi Edge with one device licensed Free Set up

Models

Specifications

The Fronius Eco is a transformerless three-phase string inverter for large rooftop and ground arrays, with one MPP tracker, six DC connections and an IP 66 enclosure. The standard version carries a Fronius Datamanager 2.0 plug-in card, which provides WLAN and Ethernet, the web interface, Modbus TCP SunSpec and Modbus RTU SunSpec.^3, 4

AC nominal output

25,000 W (25.0-3-S); 27,000 W (27.0-3-S)³

MPP trackers

1, with 6 DC connections³

DC input voltage range

580 to 1,000 V³

Grid connection

3~NPE 380 V / 220 V or 3~NPE 400 V / 230 V³

Interfaces

WLAN / Ethernet LAN (Modbus TCP SunSpec, Solar API JSON), RS485 (Modbus RTU SunSpec or meter), 2x RS422 Solar Net³

Modbus TCP port

502 preset; port 80 not allowed¹

Unit ID

Inverter number 01 to 99; 00 is unit ID 100^1, 4

Degree of protection

IP 66³

Ambient temperature range

-25 to +60 °C³

Interface

Documented measurements and integration boundaries for Eco.

• Common block, register numbers 40001 to 40069 (wire addresses 40000 to 40068): SID 'SunS' at 40001 and 40002, model ID 1 at 40003, length 65 at 40004, manufacturer, model, Datamanager firmware, inverter software and serial number strings.
• With the float setting, inverter model 113 starts at register 40070 (wire 40069) with length 60. AC power W is float32 at 40092 and 40093, frequency Hz at 40094 and 40095, and AC lifetime energy WH at 40102 and 40103 in Wh. Fronius marks WH as possibly imprecise.
• Phase currents AphA to AphC are float32 at 40074 to 40079 and phase voltages PhVphA to PhVphC at 40086 to 40091. DCW at 40108 and 40109 is the total DC power. Cabinet and heat sink temperatures are not supported.
• Operating state St is enum16 at 40118: 4 means MPPT (feeding in), 5 throttled, 7 fault and 8 standby. F_Active_State_Code at register 214 carries the inverter state code.
• With the int+SF setting the inverter model is 103 and every later model moves to a new start address. Walk the model IDs and lengths after the Common block rather than reusing the float addresses.
• System totals for every inverter on the Datamanager: F_Site_Power uint32 W at registers 500 and 501 (sent as address 499), F_Site_Energy_Total uint64 Wh at 510 to 513. These need no scale factor.
• Unsupported values read as 0x7FC00000 (NaN) for float32, 0x8000 for int16 and 0xFFFF for uint16. Store them as unavailable, not as zero.

Setup

1. Confirm the Datamanager and inverter number

   Check that the Eco carries a Fronius Datamanager 2.0 card; the light version does not. On the inverter display, DATCOM shows the inverter number (00 to 99, factory 01). That number is the Modbus unit ID, except 00, which becomes 100.

2. Turn on Modbus data output

   On the Datamanager web page, open Settings, Modbus, and set data output to tcp (or rtu for the RS485 terminals). Leave the preset port 502 unless the site uses another. Leave inverter control via Modbus off for a monitoring connection. Note the SunSpec model type: float gives inverter model 113, int+SF gives model 103.

3. Use the register numbering Fronius documents

   This guide uses operating instructions 42,0410,2049 edition 033-24022026 and map archive 1.1.7-0. Fronius numbers registers from 1, so register 40001 is sent as address 40000 (0x9C40). The manual's own example reads Mn at register 40005 by sending 01 03 9C 44 00 04 2A 4C. Read with FC03 only.

4. Find the inverter model before reading values

   Fronius states that register addresses depend on the dynamic SunSpec list. Read SID at register 40001 (two registers, expect 0x53756E53), then the model ID and length at 40070. With the float setting expect 113 and 60. Then read AC power W at 40092 as one two-register float32, big-endian.

5. Pace requests and keep scopes apart

   Send queries one at a time with a timeout of at least 10 seconds when several inverters share the ring, and read neighbouring registers in one request. F_Site_Power at 500 is the sum of all inverters on the Datamanager, not this inverter. Compare the first power read with the inverter display or Solar.web before adding further points.

Common questions

Why do the register addresses change after switching between float and int+SF?

The float inverter model 113 has 60 registers and the integer model 103 has a different length. Every model after the inverter model moves when the type changes. Read model IDs and lengths after the Common block and work with offsets, as Fronius instructs.^1, 2

Does the Fronius Eco light version support Modbus?

Not on its own. The datasheet's WLAN, Ethernet and RS485 Modbus interfaces belong to the Datamanager, and the light version has no Datamanager. Add a Datamanager 2.0 card before configuring either Modbus path.^3, 4

Can Edge limit the Eco's output over Modbus?

This guide covers monitoring only. Fronius documents power reduction and power factor registers in model 123, enabled by a separate Inverter control via Modbus setting. Control needs the site owner's and Fronius's agreement and is outside this guide.^1, 2