Eastron SEM3-WL, electricity meter, three-phase, RS485 Modbus RTU, Wi-Fi

Compact three-phase electricity meter with Wi-Fi and RS-485 communication for advanced measurement of electrical parameters.

The Eastron SEM3-WL energy meter represents a new generation of DIN rail- mounted measuring instruments. Thanks to the integrated Wi-Fi module and RS-485 interface with Modbus RTU protocol, it allows easy integration into energy management systems. The device measures and displays the characteristics of single-phase and three-phase networks, including voltage, frequency, current, power, and active and reactive energy.

With class B active energy measurement accuracy, it finds application in various applications such as photovoltaic system management, smart buildings or industrial facilities. The electricity meter can be used as one three-phase meter or three independent single-phase meters with the possibility of setting different CT ratios for each phase.

Flexible measurement modes

The SEM3-WL electricity meter offers two measurement modes. In standard mode, the supplied and consumed energy are measured separately. In PV mode, the supplied and consumed energy are first balanced, and the resulting value is included in either the supplied or consumed energy.

Communication options

The device is equipped with two communication interfaces. The RS485 interface with Modbus RTU protocol enables communication over a distance of up to 1000 ms with an adjustable baud rate of 2400 to 115200 bps. The Wi-Fi interface with Modbus TCP protocol operates in the 2.4 GHz band with a range of up to 30 m indoors and 50 m outdoors.

Accurate measurement

SEM3-WL provides high measurement accuracy: ± 1% for active energy, ± 0.5% for voltage, ± 0.5% for current in the range of 4–120 A and ± 0.2% for frequency. Active data update power is measured every 50 ms via RS-485 and 100 ms via Wi-Fi.

BASIC SPECIFICATIONS

Measurement type: RMS including harmonics in three-phase AC systems (3P, 3P+N)

Active energy measurement accuracy: ± 1% (class B)

Rated voltage: 3× 230 V (LN) / 400 V (LL)

Operating voltage range: 90 to 300 V AC (LN), 156 to 520 V AC (LL)

Frequency: 50/60Hz

Communication 1: RS-485 Modbus RTU (up to 1000 m)

Communication 2: Wi-Fi Modbus TCP (802.11 b/g/n)

RS485 baud rate: 2400 to 115200 bps

Wi-Fi band: 2.4 GHz to 2.5 GHz

Measurement modes: standard and PV mode

Network configuration: 1p2w, 3p4w, 3p3w

Mounting: on DIN rail, width 1 module