Carlo Gavazzi WM30 / WM40 Modbus register map

Modular three-phase power analyzers (96 mm panel), Modbus RTU or TCP through a communication module

Official
531 registers
Modbus TCP and RTU
Revision 2 · 2026-10-17
Identity: model, firmware

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.

Download .mbmap.json Raw JSON View on GitHub Suggest a correction Report a problem

Communication

Protocol: Modbus TCP and RTU
Unit ID: 1
TCP port: 502default
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: 125 registers per request

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

Map

Registers: 93 holding registers, 438 input registers
Groups: 11
Revision: 2 · 2026-10-17
Added: 2026-10-14 (2026-10-14)
File: maps/carlo-gavazzi/wm30-wm40.mbmap.json · 87 KB · history
SHA-256: d67ad6dcf6faea5d08fc50de3787043acd7d3df76116d7d7630ff5908272a6c9
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
Role	Register	Address	Type	Values
Firmware	Base firmware version revision	input 0	uint16 bits 0–7
Model	Carlo Gavazzi identification code	input 11	uint16	65 = WM30, 66 = WM40, 98 = WM20

Sources and notes

WM20-WM30-WM40 Communication Protocol · version rev. 3.0, 2016-02-17

Source: Carlo Gavazzi, "WM20-WM30-WM40 Communication Protocol", rev. 3.0 (2016-02-17)

FC03 or FC04 read (the same values), FC06 and FC10 write; at most 125 registers per read.
Floats and 64-bit integers are low word first (bytes high first in each word).
Firmware codes in the protocol: X = WM30, Y = WM40, Z = WM20, followed by the revision. Registers without a note are on both WM30 and WM40; most min, max and demand max values and the odd/even harmonics are WM40 only.
Not in this map: harmonic FFT blocks (0x0600-0x08D0), harmonic phase angles (0x0900), alarm set-up blocks (0x1050, 0x1500), per-variable min/max resets (0x3200) and module settings other than RS485.

Area	Address	Type	Access	Unit	Description
IR	0	uint16 bits 8–15	R		High byte: ASCII model letter (A = AV5, B = AV6, C = AV4, D = AV7); low byte: revision
IR	0	uint16 bits 0–7	R
IR	80	float32 CDAB	R	V
IR	82	float32 CDAB	R	V
IR	84	float32 CDAB	R	V
IR	86	float32 CDAB	R	V
IR	88	float32 CDAB	R	V
IR	90	float32 CDAB	R	V
IR	92	float32 CDAB	R	V
IR	94	float32 CDAB	R	V
IR	96	float32 CDAB	R	A
IR	98	float32 CDAB	R	A
IR	100	float32 CDAB	R	A
IR	102	float32 CDAB	R	A	Calculated by the base; measured by the optional module on WM40
IR	104	float32 CDAB	R	W
IR	106	float32 CDAB	R	W
IR	108	float32 CDAB	R	W
IR	110	float32 CDAB	R	W
IR	112	float32 CDAB	R	VA
IR	114	float32 CDAB	R	VA
IR	116	float32 CDAB	R	VA
IR	118	float32 CDAB	R	VA
IR	120	float32 CDAB	R	var
IR	122	float32 CDAB	R	var
IR	124	float32 CDAB	R	var
IR	126	float32 CDAB	R	var
IR	128	float32 CDAB	R		Negative = lead (C), positive = lag (L)
IR	130	float32 CDAB	R
IR	132	float32 CDAB	R
IR	134	float32 CDAB	R
IR	136	float32 CDAB	R	Hz
IR	138	float32 CDAB	R	%
IR	140	float32 CDAB	R	%
IR	142	float32 CDAB	R		+1 = L1-L2-L3, -1 = wrong sequence
IR	144	float32 CDAB	R		WM40 only
IR	146	float32 CDAB	R		WM40 only
IR	148	float32 CDAB	R		WM40 only
IR	150	float32 CDAB	R		Optional module only; WM40 only
IR	152	float32 CDAB	R		Optional module only; WM40 only
IR	160	float32 CDAB	R	%
IR	162	float32 CDAB	R	%
IR	164	float32 CDAB	R	%
IR	166	float32 CDAB	R	%
IR	168	float32 CDAB	R	%
IR	170	float32 CDAB	R	%
IR	172	float32 CDAB	R	%
IR	174	float32 CDAB	R	%
IR	176	float32 CDAB	R	%
IR	178	float32 CDAB	R	%	WM40 only
IR	180	float32 CDAB	R	%	WM40 only
IR	182	float32 CDAB	R	%	WM40 only
IR	184	float32 CDAB	R	%	WM40 only
IR	186	float32 CDAB	R	%	WM40 only
IR	188	float32 CDAB	R	%	WM40 only
IR	190	float32 CDAB	R	%	WM40 only
IR	192	float32 CDAB	R	%	WM40 only
IR	194	float32 CDAB	R	%	WM40 only
IR	196	float32 CDAB	R	%	WM40 only
IR	198	float32 CDAB	R	%	WM40 only
IR	200	float32 CDAB	R	%	WM40 only
IR	202	float32 CDAB	R	%	WM40 only
IR	204	float32 CDAB	R	%	WM40 only
IR	206	float32 CDAB	R	%	WM40 only
IR	208	float32 CDAB	R	%	WM40 only
IR	210	float32 CDAB	R	%	WM40 only
IR	212	float32 CDAB	R	%	WM40 only
IR	214	float32 CDAB	R	%	WM40 only
IR	216	float32 CDAB	R	%	WM40 only
IR	218	float32 CDAB	R	%	WM40 only
IR	336	float32 CDAB	R	V
IR	338	float32 CDAB	R	V
IR	340	float32 CDAB	R	V
IR	342	float32 CDAB	R	V
IR	344	float32 CDAB	R	V
IR	346	float32 CDAB	R	V
IR	348	float32 CDAB	R	V
IR	350	float32 CDAB	R	V
IR	352	float32 CDAB	R	A
IR	354	float32 CDAB	R	A
IR	356	float32 CDAB	R	A
IR	358	float32 CDAB	R	A
IR	360	float32 CDAB	R	W
IR	362	float32 CDAB	R	W
IR	364	float32 CDAB	R	W
IR	366	float32 CDAB	R	W
IR	368	float32 CDAB	R	VA
IR	370	float32 CDAB	R	VA
IR	372	float32 CDAB	R	VA
IR	374	float32 CDAB	R	VA
IR	376	float32 CDAB	R	var
IR	378	float32 CDAB	R	var
IR	380	float32 CDAB	R	var
IR	382	float32 CDAB	R	var
IR	384	float32 CDAB	R		Negative = lead (C), positive = lag (L)
IR	386	float32 CDAB	R
IR	388	float32 CDAB	R
IR	390	float32 CDAB	R
IR	392	float32 CDAB	R	Hz
IR	394	float32 CDAB	R	%
IR	396	float32 CDAB	R	%

Help improve this map

I tested it on a deviceReport whether it worked, even if you did not write the map.
Suggest a correctionEdit the file on GitHub; it opens a pull request.
Report a problemA wrong address, type, scale or byte order.
Read the formatWhat each key of the file means (SPEC.md).