Carlo Gavazzi ET112 (charge)
The Carlo Gavazzi ET112 is a single-phase, DIN-rail energy transducer used for active power and energy metering in residential and light commercial installations. This template targets the charge (import) role and reads two registers over Modbus RTU: instantaneous active power at address 4 and cumulative active energy at address 16. Both registers use function code 4 and a 32-bit signed integer format. Pairing the ET112 with the ModbusCloud Gateway gives installers a real-time and historical view of single-phase consumption without manual meter reads.
- Protocol
- Modbus RTU
- Connection
- RS485
- Registers
- 2, read only
- Brand
- Carlo Gavazzi
- Compatible models
- EM110/111/112 · ET112
- Last updated
Registers (2)
2 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| power | W | Read | |||
| energy | Wh | Read |
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Use cases
- Monitor instantaneous active power to detect unexpected load spikes on a single-phase circuit.
- Track cumulative energy import over time to verify EV charger or heat pump consumption figures.
- Alert on sustained high power readings that may indicate a tripped or malfunctioning connected load.
- Compare daily energy totals from the ET112 against utility billing data to spot metering discrepancies.
- Report monthly single-phase consumption per tenant or cost centre for energy cost allocation.
Installation
Set the Modbus RTU unit address on the ET112 using the front keypad or Carlo Gavazzi configuration software; the factory default address is 1.
Wire the RS485 bus from the ET112 terminals (A-, B+, GND) to the ModbusCloud Gateway RS485 port, using a twisted-pair cable and connecting terminal T to A- on the last device in the chain for bus termination.
In the ModbusCloud portal, add a new Gateway, select Modbus RTU, import the Carlo Gavazzi ET112 (charge) template, and assign the correct unit ID matching the address set on the meter.
Verify the connection by reading the power register (address 4) in the portal's live register view and confirming the value matches the reading on the ET112 display.
Things to watch for
Why does the power register return zero or a wrong sign?
The ET112 reports signed power: positive means import, negative means export. If the current transformer or line connection is reversed, the sign will flip. Check wiring polarity against the installation diagram. Also confirm the measurement mode on the meter is not set to easy-connection mode, which sums absolute energy and ignores direction.
The gateway connects but no register values appear. What now?
Verify the unit ID in the portal matches the Modbus address programmed on the ET112 (default 1). Check RS485 wiring polarity (A- and B+) and ensure bus termination is applied at the last device by connecting terminal T to A-. A missing termination is a common cause of intermittent or absent responses on longer runs.
Register reads return an illegal data address error. What is wrong?
The ET112 communication protocol explicitly states that reading addresses outside the documented register map returns an illegal data address exception. Confirm you are using function code 4 (Read Input Registers) and physical addresses 4 and 16. Do not attempt to access undocumented addresses.
The energy value looks correct but does not reset or match expectations.
The energy register at address 16 is a cumulative totalizer. It does not reset automatically. If the meter was replaced or reset via the keypad, the baseline in the portal will shift. Use the portal's delta calculation on historical data to derive consumption over any chosen period rather than relying on the raw register value alone.
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