MBMap Registry
  1. Devices
  2. Carlo Gavazzi
  3. ET330

Carlo Gavazzi ET330 Modbus register map

Three-phase bidirectional energy meter with CT connection (DIN rail), RS485 Modbus RTU

  • Official
  • 107 registers
  • Modbus RTU
  • Revision 2 · 2026-10-17
  • Identity: model

Official: Written from the manufacturer's documentation, but not tested on a device yet. Check the map against the manufacturer's documentation before you write to a live device. Tested it? Report a test.

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Communication

Protocol
Modbus RTU
Unit ID
1
Serial
9600 8N1 · 9600 baud, 8 data bits, none parity, 1 stop bit
Byte / word order
CDAB · bytes big-endian, words low first (word swap)
Addresses
0-based
Max read
50 registers per request

Connection values are defaults: the device may be configured differently.

Map

Registers
33 holding registers, 74 input registers
Groups
6
Revision
2 · 2026-10-17
Added
()
File
maps/carlo-gavazzi/et330.mbmap.json · 19 KB · history
SHA-256
9bbec9bb0144979cb5dc932a8bd850a1388def487a969736269535be793d7304
Manufacturer
gavazziautomation.com

Device identity

What a tool can read to check that this map fits the connected device (SPEC.md section 4.7). Registers with a role are read like any other register.

Registers
RoleRegisterAddressTypeValues
Model Carlo Gavazzi identification code input 11 uint16 335 = ET330, 336 = ET330

Sources and notes

Source: Carlo Gavazzi, "EM300 Series and ET300 Series Communication Protocol", version 2 revision 17 (2021-07-05)

  • One protocol document covers EM330, EM340, ET330 and ET340; registers marked ET series or EM330 are not on the other models.
  • FC03 or FC04 read (the same values), FC06 writes one register; at most 50 registers per read.
  • 32- and 64-bit values are low word first (bytes high first in each word).
  • Overflow (EEE on the display) reads 7FFFFFFFh in the variable.
  • The high-resolution energy registers from 0x0500 are only on EM330 made from October 2018; EM340 from that date has integer and decimal parts at 0x0400 (not in this map).
AreaAddressNameTypeAccessUnitScaleDescription
IR 11 uint16 R Read alone, one word at a time: the same address is the high word of V L3-L1
IR 0 int32 CDAB R V ×0.1
IR 2 int32 CDAB R V ×0.1
IR 4 int32 CDAB R V ×0.1
IR 6 int32 CDAB R V ×0.1
IR 8 int32 CDAB R V ×0.1
IR 10 int32 CDAB R V ×0.1
IR 12 int32 CDAB R A ×0.001
IR 14 int32 CDAB R A ×0.001
IR 16 int32 CDAB R A ×0.001
IR 18 int32 CDAB R W ×0.1
IR 20 int32 CDAB R W ×0.1
IR 22 int32 CDAB R W ×0.1
IR 24 int32 CDAB R VA ×0.1
IR 26 int32 CDAB R VA ×0.1
IR 28 int32 CDAB R VA ×0.1
IR 30 int32 CDAB R var ×0.1
IR 32 int32 CDAB R var ×0.1
IR 34 int32 CDAB R var ×0.1
IR 36 int32 CDAB R V ×0.1
IR 38 int32 CDAB R V ×0.1
IR 40 int32 CDAB R W ×0.1
IR 42 int32 CDAB R VA ×0.1
IR 44 int32 CDAB R var ×0.1
IR 46 int16 R ×0.001 Negative = exported active power
IR 47 int16 R ×0.001 Negative = exported active power
IR 48 int16 R ×0.001 Negative = exported active power
IR 49 int16 R ×0.001 Negative = exported active power
IR 50 int16 R
IR 51 int16 R Hz ×0.1
IR 52 int32 CDAB R kWh ×0.1
IR 54 int32 CDAB R kvarh ×0.1
IR 56 int32 CDAB R W ×0.1
IR 58 int32 CDAB R W ×0.1
IR 60 int32 CDAB R kWh ×0.1
IR 62 int32 CDAB R kvarh ×0.1
IR 64 int32 CDAB R kWh ×0.1
IR 66 int32 CDAB R kWh ×0.1
IR 68 int32 CDAB R kWh ×0.1
IR 70 int32 CDAB R kWh ×0.1
IR 72 int32 CDAB R kWh ×0.1
IR 78 int32 CDAB R kWh ×0.1
IR 80 int32 CDAB R kvarh ×0.1
IR 96 int32 CDAB R kWh ×0.1 ET series only
IR 98 int32 CDAB R kWh ×0.1 ET series only
IR 100 int32 CDAB R kWh ×0.1 ET series only
IR 130 int32 CDAB R % ×0.01
IR 132 int32 CDAB R % ×0.01
IR 134 int32 CDAB R % ×0.01
IR 136 int32 CDAB R % ×0.01
IR 138 int32 CDAB R % ×0.01
IR 140 int32 CDAB R % ×0.01
IR 142 int32 CDAB R % ×0.01
IR 152 int32 CDAB R A ×0.001 ET series and EM330
IR 1280 int64 CDAB R kWh; EM330 made from October 2018; the protocol gives no value weight
IR 1284 int64 CDAB R kvarh
IR 1288 int64 CDAB R kWh
IR 1292 int64 CDAB R kvarh
IR 1296 int64 CDAB R kWh
IR 1300 int64 CDAB R kWh
IR 1304 int64 CDAB R kWh
IR 1308 int64 CDAB R kWh
IR 1312 int64 CDAB R kWh
IR 1316 int64 CDAB R kvarh
IR 1320 int64 CDAB R kvarh
IR 770 uint16 R 0 = A, 1 = B …
IR 771 uint16 R
HR 4096 uint16 RW EM only; always 0 on ET
HR 4098 uint16 RW
HR 4099 uint32 CDAB RW ×0.1 (CT ratio)×(VT ratio) is at most 1057 on AV5 and 3418 on AV6
HR 4101 uint32 CDAB RW ×0.1
HR 4112 uint32 CDAB RW min
HR 4114 uint32 CDAB RW
HR 4128 uint32 CDAB RW
HR 4130 uint32 CDAB RW
HR 4352 uint16 RW
HR 4353 uint16 RW
HR 4354 uint16 RW EM only; not changeable on MID versions
HR 4355 uint16 RW
HR 4356 uint16 RW
HR 4357 bool bit 0 R
HR 4357 bool bit 1 R
HR 4357 bool bit 2 R
HR 4357 bool bit 3 R
HR 4357 bool bit 4 R
HR 4357 bool bit 5 R
HR 4357 bool bit 6 R
HR 4357 bool bit 7 R
HR 4358 uint16 RW ET series and EM330
HR 4359 uint32 CDAB RW A ×0.001 Secondary current; ET series and EM330
HR 4608 uint16 RW
HR 4609 uint16 RW
HR 8192 uint16 RW
HR 8193 uint16 RW
HR 8194 uint16 RW
HR 8195 uint16 RW 2 only with no parity
HR 8196 uint16 R
HR 16384 uint16 W
HR 16385 uint16 W Non-MID (X) versions only
HR 16386 uint16 W ET series and EM330

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