Carlo Gavazzi ET112
Single-phase energy transducer
A single-phase energy transducer with no display, two DIN modules wide, for direct connection up to 100 A. It measures imported and exported energy with Class 1 accuracy and is read entirely over its RS-485 Modbus port.
Also sold asET112-DIN
Compatibility
Compatible with EpiSensor Edge over Modbus RTU.
Connect its RS-485 port to a Modbus Interface or to a serial interface on the Gateway. Edge polls it with its Modbus client.
Edge reads 18 values from it, listed under Interface.
Connect it with
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Modbus Interface ZMB-3XFrom €399 ex VAT Configure Modbus Interface
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Gateway ZGW-20From €899 ex VAT Configure Gateway
Specifications
The ET112 is a single-phase, two-wire energy transducer in a 2-module DIN-rail housing, connected directly to circuits up to 100 A. It has no display: two LEDs show power, communication and energy pulses, and every reading comes over Modbus. It measures voltage, current, active, apparent and reactive power, power factor and frequency, keeps imported and exported kWh and kvarh, two tariffs, power demand and a run-hour meter.12
- Power
- Self-powered from the measured supply. Powered from the measured voltage, from 30 % below to 20 % above its rating, drawing up to 1 W and 8 VA.1
- Current
- 5(100) A direct connection1
- Voltage (AV0)
- 120 to 240 V L-N AC; 230 V L-N before June 20261
- Frequency
- 45 to 65 Hz1
- Active energy accuracy
- Class 1 (EN 62053-21)1
- Reactive energy accuracy
- Class 2 (EN 62053-23)1
- Voltage and current accuracy
- ±0.5 % of reading1
- RS-485 port
- Modbus RTU on screw terminals and two RJ45 sockets, 1/8 unit load, up to 247 devices1
- Read command
- 125 words in one request (50 on units made before June 2026)1
- Optical port
- Front infrared port for the OptoProg interface1
- Digital input
- One voltage-free input for tariff switching1
- Dimensions
- 35 × 63 × 90 mm, 2 DIN modules1
- Protection
- IP20 front and terminals1
- Operating temperature
- -40 to 65 °C indoor (-25 °C minimum before June 2026)1
Where it is used
Solar PV inverter and battery circuits up to 100 A, reading generation and export from one transducer in bidirectional mode.
Solar PV monitoringMetering single-phase EV chargers for load management, where a display is not needed.
EV charging load managementCost allocation on single-phase circuits in a distribution board, daisy-chained over the RJ45 sockets.
Tenant submetering and cost allocation
Interface
This register map is for the ET112-DIN AV0 1 X S1 X.
Communication settings
- Protocol
- Modbus RTU (JBUS) over RS-485
- Unit address
- 1 to 247, default 1
- Baud rate
- 9600 (default), 19200, 38400, 57600 or 115200 bit/s
- Parity and stop bits
- No parity (default) or even parity; 2 stop bits only without parity
- Timing
- 40 ms typical and 500 ms maximum answering time
- Read with
- FC04 (FC03 returns the same values)
- Word order
- Low word first on each 32-bit value
- Addresses
- Zero-based PDU addresses, as sent on the bus
From EM100 Series and ET100 Series communication protocol, version 2 revision 143.
Register map
| Point | Address | Hex | Format | Scale | Unit |
|---|---|---|---|---|---|
| Voltage | 0 | 0x0000 |
INT32 | ×0.1 | V |
| Current | 2 | 0x0002 |
INT32 | ×0.001 | A |
| Active Power | 4 | 0x0004 |
INT32 | ×0.1 | W |
| Apparent Power | 6 | 0x0006 |
INT32 | ×0.1 | VA |
| Reactive Power | 8 | 0x0008 |
INT32 | ×0.1 | VAr |
| Active Power Demand | 10 | 0x000A |
INT32 | ×0.1 | W |
| Peak Active Power Demand | 12 | 0x000C |
INT32 | ×0.1 | W |
| Power Factor | 14 | 0x000E |
INT16 | ×0.001 | - |
| Frequency | 15 | 0x000F |
INT16 | ×0.1 | Hz |
| Import Active Energy | 16 | 0x0010 |
INT32 | ×0.1 | kWh |
| Import Reactive Energy | 18 | 0x0012 |
INT32 | ×0.1 | kVArh |
| Partial Import Active Energy | 20 | 0x0014 |
INT32 | ×0.1 | kWh |
| Partial Import Reactive Energy | 22 | 0x0016 |
INT32 | ×0.1 | kVArh |
| Import Active Energy Tariff 1 | 24 | 0x0018 |
INT32 | ×0.1 | kWh |
| Import Active Energy Tariff 2 | 26 | 0x001A |
INT32 | ×0.1 | kWh |
| Export Active Energy | 32 | 0x0020 |
INT32 | ×0.1 | kWh |
| Export Reactive Energy | 34 | 0x0022 |
INT32 | ×0.1 | kVArh |
| Run Hours | 44 | 0x002C |
INT32 | ×0.01 | h |
Edge template
This JSON file supplies the register map. Applying it to an existing meter replaces its sensor list while retaining the site connection, unit ID and enable state.
| Model | Connection | Points | Version | Updated | Download |
|---|---|---|---|---|---|
| ET112-DIN AV0 1 X S1 X | Modbus RTU (JBUS) over RS-485 | 18 | 1.0.0 | Download |
Downloads need a signed-in account with Edge download access.
Use the template in Edge
- Import the JSON file
On the target Gateway in Edge, open Settings, then Device Templates. Choose Import and select the downloaded JSON file. Confirm that the model and template name match your device.
- Load the map for your meter
In the Modbus device wizard, choose the site connection and unit ID, then use Load Template to select the imported map. For an existing device, apply the template to that exact model. Its connection, unit ID and enable state are retained.
- Test a reading
Use Test in the wizard and compare a known reading with the meter display. Check its unit, sign and scale, then confirm that timestamps keep advancing. These starter maps are read-only and leave exports off until you configure them.
Setup
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Wire the bus
Connect the RS-485 pair to the screw terminals or plug into one of the two RJ45 sockets (pin 4 B+, pin 5 A-, pin 8 GND). Only one of the parallel ports can be in use at a time.2
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Terminate the last transducer
Link terminals A- and T on the last device on the bus, and fit 120 Ω across A and B at the master end. Beyond 1,000 m or 160 devices, add a repeater.3
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Set a unique address
Every ET112 ships at address 1, 9600 bit/s and no parity. With more than one on the bus, connect them one at a time and write a new address to holding register 2000h, or set it with the configuration software through the optical port.3
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Choose the measurement mode
Leave Measure = A to count all energy as imported, or set Measure = b to count imported and exported energy separately. Over Modbus the mode is holding register 1103h: write 1 twice to switch to b, because the register toggles.3
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Read the identification code
Import the Edge template, then read register 11 (000Bh) on its own: a 230 V ET112 answers 120 and a 120 V model 121. Then check Voltage at register 0 against a meter on the same circuit.3
Common questions
- Why does exported energy stay at zero?
- The ET112 ships in easy connection mode (Measure = A), which adds energy in either direction to imported kWh. Set it to bidirectional mode (Measure = b) and export is counted in its own register at address 32.13
- How do I configure it without a display?
- Over Modbus, by writing its holding registers with FC06, or with Carlo Gavazzi's configuration software through the OptoProg optical interface on the front.13
- How are 32-bit values ordered?
- Least significant word first, with the most significant byte first inside each word. In Edge that is big-endian bytes with word swap on every INT32 register. Power factor and frequency are single 16-bit registers.3
- Can the ET112 be used for billing?
- The ET112 is Class 1 to EN 62053-21 and carries CE and UKCA marks. Its datasheet lists no MID certification, so use a MID-certified meter where billing requires one.14
- How many ET112s can share one bus?
- Up to 247 on the same RS-485 bus, since each is 1/8 unit load. Give each a unique address and terminate only the last one on the line.1
Related devices
Sources
- ET112 single-phase energy transducer datasheet (DS 110526) (opens in a new tab) (PDF)
- ET112 installation manual (opens in a new tab) (PDF)
- EM100 Series and ET100 Series communication protocol, version 2 revision 14 (opens in a new tab) (PDF)
- ET112DINAV01XS1X product page (opens in a new tab)
- Carlo Gavazzi ET112 device template (opens in a new tab)
Further reading
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