Legrand EMDX3 multifunction meter (4 120 45)

Register map(s) for this device, with a note of how far each has been checked. Addresses are 0-based, as on the wire. Scale and byte order are confirmed only at the hardware-verified rung.

coherence-checked

Round-trips through a real Modbus stack with no overlapping addresses and a word-order-sensitive codec — the map is internally coherent and wire-decodable. Does NOT prove byte-order or scaling match a real device: the emulator is seeded from the map's own types, so a uniformly wrong byte-order still round-trips. Only hardware-verified confirms byte-order/scale on the wire.

point	address (0-based)	type	scale	unit
Write Current transformer ratio - CT	256	U16	1
Device identifier	768	U16	0.01
Phase 1 : phase voltage	4096	U32BE	1	mV
Phase 2 : phase voltage	4098	U32BE	1	mV
Phase 3 : phase voltage	4100	U32BE	1	mV
Phase 1 : current	4102	U32BE	1	mA
Phase 2 : current	4104	U32BE	1	mA
Phase 3 : current	4106	U32BE	1	mA
Neutral current	4108	U32BE	1	mA
Chained voltage : L1-L2	4110	U32BE	1	mV
Chained voltage : L2-L3	4112	U32BE	1	mV
Chained voltage : L3-L1	4114	U32BE	1	mV
3-phase : active power	4116	U32BE	1	W
3-phase : reactive power	4118	U32BE	1	var
3-phase : apparent power	4120	U32BE	1	VA
3-phase : sign of active power	4122	U16	1
3-phase : sign of reactive power	4123	U16	1
3-phase : positive active energy	4124	U32BE	1	Wh
3-phase : positive reactive energy	4126	U32BE	1	varh
3-phase : negative active energy	4128	U32BE	1	Wh
3-phase : negative reactive energy	4130	U32BE	1	varh
3-phase : power factor	4132	I16	0.01
3-phase : sector of power factor (cap or ind)	4133	U16	1
Frequency	4134	U16	0.1	Hz
3-phase : average power	4135	U32BE	1	W
3-phase : peak maximum demand	4137	U32BE	1	W
Time counter for average power	4139	U16	1	min
Phase 1 : active power	4140	U32BE	1	W
Phase 2 : active power	4142	U32BE	1	W
Phase 3 : active power	4144	U32BE	1	W
Phase 1 : sign of active power	4146	U16	1
Phase 2 : sign of active power	4147	U16	1
Phase 3 : sign of active power	4148	U16	1
Phase 1 : reactive power	4149	U32BE	1	var
Phase 2 : reactive power	4151	U32BE	1	var
Phase 3 : reactive power	4153	U32BE	1	var
Phase 1 : sign of reactive power	4155	U16	1
Phase 2 : sign of reactive power	4156	U16	1
Phase 3 : sign of reactive power	4157	U16	1
Phase 1 : apparent power	4158	U32BE	1	VA
Phase 2 : apparent power	4160	U32BE	1	VA
Phase 3 : apparent power	4162	U32BE	1	VA
Phase 1 : power factor	4164	I16	0.01
Phase 2 : power factor	4165	I16	0.01
Phase 3 : power factor	4166	I16	0.01
Phase 1 : sector of power factor (cap or ind)	4167	U16	1
Phase 2 : sector of power factor (cap or ind)	4168	U16	1
Phase 3 : sector of power factor (cap or ind)	4169	U16	1
Phase 1 : THD V1	4170	U16	0.1	%
Phase 2 : THD V2	4171	U16	0.1	%
Phase 3 : THD V3	4172	U16	0.1	%
Phase 1 : THD I1	4173	U16	0.1	%
Phase 2 : THD I2	4174	U16	0.1	%
Phase 3 : THD I3	4175	U16	0.1	%
Phase 1 : I1 average	4176	U32BE	1	mA
Phase 2 : I2 average	4178	U32BE	1	mA
Phase 3 : I3 average	4180	U32BE	1	mA
Phase 1 : I1 peak Max.	4182	U32BE	1	mA
Phase 2 : I2 peak Max.	4184	U32BE	1	mA
Phase 3 : I3 peak Max.	4186	U32BE	1	mA
3-phase : I average	4188	U32BE	1	mA
Phase 1 : V1 min.	4190	U32BE	1	mV
Phase 2 : V2 min.	4192	U32BE	1	mV
Phase 3 : V3 min.	4194	U32BE	1	mV
Phase 1 : V1 Max.	4196	U32BE	1	mV
Phase 2 : V2 Max.	4198	U32BE	1	mV
Phase 3 : V3 Max.	4200	U32BE	1	mV
3-phase : partial active energy	4202	U32BE	1	Wh
3-phase : partial reactive energy	4204	U32BE	1	varh
Operating timer counter	4206	U16	1	h
3-phase : average active power	4208	U32BE	1	W
3-phase : average reactive power	4210	U32BE	1	var
3-phase : average apparent power	4212	U32BE	1	VA
3-phase : active PMD power	4214	U32BE	1	W
3-phase : reactive PMD power	4216	U32BE	1	var
3-phase : apparent PMD power	4218	U32BE	1	VA
Operating timer counter	4220	U32BE	1	minutes
Current transformer ratio (CT)	4608	U16	1
Device identifier	4612	U16	0.01
Signed Total active power	5400	I32BE	1	W
Signed Total reactive power	5402	I32BE	1	var
Signed phase1 active power	5404	I32BE	1	W
Signed phase2 active power	5406	I32BE	1	W
Signed phase3 active power	5408	I32BE	1	W
Signed phase1 reactive power	5410	I32BE	1	Var
Signed phase2 reactive power	5412	I32BE	1	Var
Signed phase3 reactive power	5414	I32BE	1	var
Signed total Power Factor	5416	I32BE	0.001
Signed phase1 Power Factor	5418	I32BE	0.001
Signed phase2 Power Factor	5420	I32BE	0.001
Signed phase3 Power Factor	5422	I32BE	0.001
Total Apparent power	5424	U32BE	1	VA
3-phase : average active power	5426	U32BE	1	W
3-phase : average reactive power	5428	U32BE	1	var
3-phase : average apparent power	5430	U32BE	1	VA
3-phase : max active power	5432	U32BE	1	W
3-phase : max reactive power	5434	U32BE	1	var
3-phase : max apparent power	5436	U32BE	1	VA
Wrap round positive active energy	5440	U16	1
Wrap round positive reactive energy	5441	U16	1
Wrap round negative active energy	5442	U16	1
Wrap round negative reactive energy	5443	U16	1
Low Positive Active Energy	5888	U32BE	1	Wh
High Positive Active Energy	5890	U32BE	1	MWh
Low Positive Reactive Energy	5892	U32BE	1	varh
High Positive Reactive Energy	5894	U32BE	1	Mvarh
Low Negative Active Energy	5896	U32BE	1	Wh
High Negative Active Energy	5898	U32BE	1	MWh
Low Negative Reactive Energy	5900	U32BE	1	varh
High Negative Reactive Energy	5902	U32BE	1	Mvarh
Low Partial Active Energy	5904	U32BE	1	Wh
High Partial Active Energy	5906	U32BE	1	MWh
Low Partial Reactive Energy	5908	U32BE	1	varh
High Partial Reactive Energy	5910	U32BE	1	Mvarh
Low Negative Partial Active Energy	5912	U32BE	1	Wh
High Negative Partial Active Energy	5914	U32BE	1	MWh
Low Negative Partial Reactive Energy	5916	U32BE	1	varh
High Negative Partial Reactive Energy	5918	U32BE	1	Mvarh
Percentage of rated 3phase active power run hour meter	8196	U16	0.01	%
Run hour meter active on	8197	U16	1
Power Averaging time	8202	U16	1
Insertion type	8203	U16	1
Measure on line 1 of custom page	8204	U16	1
Measure on line 2 of custom page	8205	U16	1
Measure on line 3 of custom page	8206	U16	1
Pulse duration	8715	U16	1
Pulse weight	8716	U16	1
Pulse active on	8717	U16	1
Reset parameters	9216	U16	1
Saving in EEPROM parameters changed by Remote commands	9728	U16	1
Enable Remote Writing Operation	9984	U16	1
Restore default parameters	10240	U16	1

link settings as documented (unverified): RTU; FC 03,16

bench facts as documented (unverified)

terminals	two-wire configuration
connector	standard EIA/TIA 485 (RS-485)
response timeout	300 ms
inter-frame delay	20 ms
model register	768

field reports — community-sourced, unverified (checked 2026-06-11)

The official Legrand Modbus Table document lists the measurement registers under the section 'INPUT REGISTERS - Words (R)'. However, attempting to read these registers using Modbus Function Code 04 (Read Input Registers) results in an 'Illegal Function' error. The device actually requires Function Code 03 (Read Holding Registers) to read these values, as specified in the 'Read Function Code' column of the table. [source]
confirmed: comms framing RTU, function codes 3 and 16, and 1 stop bit — confirmed by Legrand EMDX3 Cat.No 4 120 45 Modbus Table document
confirmed: model register 768 — confirmed by Legrand EMDX3 Cat.No 4 120 45 Modbus Table document
confirmed: physical connector standard EIA/TIA 485 (RS-485) and two-wire configuration — confirmed by Legrand EMDX3 Cat.No 4 120 45 Modbus Table document
confirmed: inter-frame delay of 20ms and response timeout of 300ms — confirmed by Legrand EMDX3 Cat.No 4 120 45 Modbus Table document
confirmed: register map addresses (phase_1_voltage @ 4096, phase_1_current @ 4102, three_phase_active_power @ 4116, three_phase_positive_active_energy @ 4124, frequency @ 4134, phase_1_thd_v1 @ 4170) — confirmed by Legrand EMDX3 Cat.No 4 120 45 Modbus Table document

The trust ladder

Each rung states what it proved and what it did not. Gray until proven; green is earned by hardware only.

generated — A prompt produced it. Unproven — anyone can regenerate this.
structure-verified — Decode path is structurally sound (addresses, widths, finite values). Does NOT prove word order or scaling.
coherence-checked — Round-trips through a real Modbus stack with no overlapping addresses and a word-order-sensitive codec — the map is internally coherent and wire-decodable. Does NOT prove byte-order or scaling match a real device: the emulator is seeded from the map's own types, so a uniformly wrong byte-order still round-trips. Only hardware-verified confirms byte-order/scale on the wire.
hardware-verified (software-key) x1 — Matched a real device with operator-attested readings as ground truth — the only rung that confirms word order + scaling on the wire.

Device not here? Upload its manual and get a checked map back. It's free.

Want it confirmed against your own device? Order hardware verification. If it doesn't check out, you don't pay.

Building on a lot of devices? License the library — machine-readable maps, the firmware matrix, and API access.