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Eastron Modbus register maps

Updated 28 October 2026

4 Eastron models, 282 registers in all, each re-typed from Eastron’s own free documentation and checked against it.

• Energy meter

  Eastron SDM120CT-40mA

  Eastron SDM120CT-40mA single-phase CT-connected DIN-rail meter with RS485 Modbus RTU, user manual V1.0 (2026-07-16).

  31 registers · 10 writable · RTU
  Also known as: SDM120CT-M-40mA, SDM120CT-M 40mA
• Energy meter

  Eastron SDM230-DI

  Eastron SDM230-DI single-phase 100 A DIN-rail meter with two digital inputs and RS485 Modbus RTU, manual 2025 V1.00.

  41 registers · 12 writable · RTU
  Also known as: SDM230 DI
• Energy meter

  Eastron SDM630-DI

  Eastron SDM630-DI three-phase DIN-rail meter (100 A direct, two digital inputs, RS485 Modbus RTU), manual V1.02.

  101 registers · 9 writable · RTU
  Also known as: SDM630 DI
• Energy meter

  Eastron SDM630MCT

  Eastron SDM630MCT three-phase CT-connected DIN-rail meter with RS485 Modbus RTU, protocol implementation V1.7.

  109 registers · 12 writable · RTU
  Also known as: SDM630 MCT

Eastron: default communication settings

Factory defaults as the manufacturer documents them. Change one setting at a time on site and write down what you changed. Word order applies to 32-bit values; the addressing column says how the manufacturer prints register numbers (every map on this site also gives the 0-based wire address).