Eastron SDM120M
Monitors single-phase energy metering via Modbus RTU.
This ModbusCloud template reads voltage, current, power, energy, and power quality metrics from an Eastron SDM120M single-phase energy meter over Modbus RTU at 19200 baud with odd parity. Eighteen float32 registers cover active, reactive, and apparent power, energy consumption and production, and demand metrics. It is a popular meter for single-phase submetering and PV monitoring applications.
- Protocol
- Modbus RTU
- Connection
- RS485, 19200 baud
- Registers
- 18, read only
- Brand
- Eastron
- Key readings
- Voltage · Current · Active power · Apparent power · Reactive power · Energy consumption and production
- Compatible models
- SDM120M
- Last updated
Registers (18)
18 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| Voltage | V | Read | |||
| Current | A | Read | |||
| Power | W | Read | |||
| Max. current demand | A | Read | |||
| Apparent power | VA | Read | |||
| Reactive power | var | Read | |||
| Power Factor | Read | ||||
| Frequency | Hz | Read | |||
| Energy Consumption | kWh | Read | |||
| Total active energy | kWh | Read | |||
| Total reactive energy | kvar | Read | |||
| Energy Production | kWh | Read | |||
| Energy Consumption Reactive | kvarch | Read | |||
| Energy Production Reactive | kvarch | Read | |||
| Total system power demand | W | Read | |||
| Max. import system power demand | W | Read | |||
| Export system power demand | W | Read | |||
| Max. export system power demand | W | Read |
Loading registers…
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Submeter a single EV charger to bill charging sessions separately from household consumption.
- Measure PV production on a single-phase installation for feed-in tariff compliance.
- Track tenant consumption in multi-unit residential buildings without a three-phase meter.
- Monitor power factor and demand to spot poor-quality loads that waste apparent power.
Installation
Wire the SDM120M A and B RS485 terminals to the ModbusCloud gateway RS485 channel.
Verify default settings on the meter display: address 4, 19200 baud, odd parity, 1 stop bit.
In ModbusCloud, add a Modbus RTU device matching those settings and import the Eastron SDM120M template.
Cross-check the first reading against the meter display to confirm correct decoding.
Things to watch for
My meter is at 9600 baud, not 19200. Can I still use this template?
Yes. Change the baudrate in the ModbusCloud device settings to 9600 to match the meter. The template registers themselves are the same regardless of baudrate.
Why are there separate import and export energy registers on a single-phase meter?
For PV applications where the meter sits on a feeder that can both consume and export electricity, these two counters track the directions separately. Even for a pure consumption meter these registers exist and export will simply stay at zero.
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