Read voltage, current, power, power factor, frequency and energy from an Eastron SDM630 three-phase energy meter over Modbus RTU. This guide gives the full register map, FLOAT32 decoding, the FC04 input-register detail that trips people up, and how to get live data — and log it — with ModbusManager on Windows.
Windows 10/11 · Modbus RTU & TCP · one-time license
The SDM630 register layout is so widely used that other meters clone it — learn it once and you can read many devices.
Eastron’s SDM630 is the most widely deployed three-phase Modbus energy meter in the European prosumer and installer market — MID-certified, direct 100 A connection (or CT version), and around 100 Modbus registers covering everything from per-phase voltage to total energy. Its register map has become the de facto reference: the SDM630MCT and SDM630-TCP variants share it, and many Carlo Gavazzi and clone meters follow the same FLOAT32 layout. If you can read an SDM630, you can read most three-phase Modbus meters.
A free ModbusManager Pro workspace with the SDM630 register map already set up: Float32 tags and an energy-meter dashboard. Open it and point it at your meter.
The workspace polls input registers from 30001 (FC04) and decodes voltage, current, power, power factor and frequency as 32-bit floats — no scripting, no manual word-pairing. Every value lands on a clean dashboard ready to read. Set your meter’s slave ID and connection, and you have live data in seconds.
Open in ModbusManager Pro · 📋 Workspace → open · needs the Float32 tag type (v1.6+)
Set these from the meter’s front panel (SET menu), then match them in ModbusManager.
| Setting | Typical value |
|---|---|
| Protocol | Modbus RTU (2-wire RS-485) |
| Baud rate | 9600 (also 2400/4800/19200/38400) |
| Parity | None (1 stop bit) — default |
| Node address | 1–247 (set on meter) |
| Function code (measurements) | 04 — input registers |
| Function code (config) | 03 read / 16 write — holding registers |
| Data type | FLOAT32 (2 registers, big-endian) |
All values are FLOAT32 (two registers each), read with function code 04. Addresses use the 1-based 30001 input-register numbering from the Eastron protocol.
| Register | Measurement | Unit | Type |
|---|---|---|---|
| 30001 | Voltage L1-N | V | FLOAT32 |
| 30003 | Voltage L2-N | V | FLOAT32 |
| 30005 | Voltage L3-N | V | FLOAT32 |
| 30007 | Current L1 | A | FLOAT32 |
| 30009 | Current L2 | A | FLOAT32 |
| 30011 | Current L3 | A | FLOAT32 |
| 30013 | Active Power L1 | W | FLOAT32 |
| 30015 | Active Power L2 | W | FLOAT32 |
| 30017 | Active Power L3 | W | FLOAT32 |
| 30053 | Total Active Power | W | FLOAT32 |
| 30071 | Total Power Factor | — | FLOAT32 |
| 30077 | Frequency | Hz | FLOAT32 |
| 30073 | Total Import Active Energy | kWh | FLOAT32 |
| 30075 | Total Export Active Energy | kWh | FLOAT32 |
The SDM630 exposes around 100 registers in total, including per-phase apparent and reactive power, per-phase power factor, THD and demand values. The full list is in the Eastron SDM630 Modbus protocol document; the registers above are the most commonly polled.
From wiring to live values in a few minutes.
ModbusManager reads any SDM630 register directly, with built-in FLOAT32 decoding so you do not combine register pairs by hand, and a serial monitor to see every frame. The Standard edition ($49) covers polling, scaling and the serial monitor. The Pro edition ($119) adds a drag-and-drop dashboard, a data logging Historian with CSV export for energy and load profiling, and an alarm system — all running locally on Windows, with no SCADA server or cloud account.
Download ModbusManager and connect to your meter over RTU. Free 14-day Pro trial — no credit card, no cloud.
Windows 10/11 · Standard $49 · Pro $119 one-time
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