Single Phase DIN Rail Energy Meter 40mA CT Modbus | Eastron SDM120CTM

The Eastron SDM120CTM is a single phase multifunction DIN rail energy meter supplied with a 40mA CT current transformer. It measures a wide range of electrical parameters and communicates over RS485 Modbus RTU, making it suitable for use alongside major solar inverter brands for export control and self-consumption monitoring. This is the 40mA CT variant; a 100mA version is sold separately.

Single phase DIN rail meter features

• CT included, supplied with a 40mA current transformer
• Measurements, kWh, kVArh, kW, kVAr, kVA, PF, Hz, V, A and more
• Bi-directional, records both import and export energy
• Communication, RS485 Modbus RTU
• Pulse outputs, two configurable outputs
• Display, white backlit LCD
• Accuracy, better than Class 1
• Format, compact DIN 43880 case, 35mm rail mounting
• Protection rating, IP51, for indoor use

Product overview

Built for residential, utility and industrial single phase applications, the bi-directional measurement makes this meter well suited to solar PV monitoring. It lets an inverter or energy management system track consumption drawn from the grid alongside any surplus exported.

The RS485 port supports Modbus RTU at 1200 to 9600 bps, with configurable parity, stop bits and a Modbus address from 1 to 247. Pulse output 1 can be set to total, import or export kWh or kVArh. Pulse output 2 is fixed at total kWh, at 1000 imp/kWh.

Inverter compatibility

The SDM120CTM 40mA works with a range of solar inverter brands. Always check the CT rating your inverter requires before ordering: this is the 40mA variant, and using the wrong CT rating will give incorrect readings.

Applications

• Solar PV export and self-consumption monitoring
• Zero export control with compatible hybrid inverters
• Residential and small commercial energy metering
• DIN rail panel installations

Installation and safety notes

This meter operates at mains voltage and must be installed by a qualified electrician in line with IET Wiring Regulations. Confirm the CT rating matches your inverter's requirements before fitting. The unit carries an IP51 rating and is for indoor use only.