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

Eastron SEM3-WL — three-phase electricity meter with Wi-Fi

In modern energy management, accurate and reliable measurement of electrical parameters is key. The Eastron SEM3-WL electricity meter is designed for easy integration into a wide range of systems thanks to Wi-Fi connection (Modbus TCP) and RS-485 interface (Modbus RTU). This compact device with a width of only 1 module on a DIN rail allows the measurement of voltage, current, power and energy in three-phase and single-phase networks. Flexibility in configuration (for example, the ability to operate as one three-phase or three single-phase meters) makes it ideal for applications in industrial facilities, photovoltaic systems and smart buildings.

Flexible measurement modes for various applications

Eastron SEM3-WL offers two measurement modes to meet the requirements of different types of installations. In standard mode, the electricity meter separately measures and records the supplied and consumed energy, which is useful for traditional applications. In PV mode, designed for photovoltaic systems, energy balancing occurs, where the resulting value corresponds to either the supplied or consumed energy. This functionality ensures optimal monitoring of production and consumption for renewable sources.

Advanced communication and easy installation

The combination of Wi-Fi connection (2.4 GHz) and RS-485 interface with a range of up to 1000 m provides users with flexibility in connecting to various types of systems. Thanks to the transmission speed 2400 to 115200 bps, the electricity meter can be easily integrated into both local and remote applications. The compact design and practical spring and RJ terminals reduce installation time and costs, making the device suitable even for limited spaces.

Measurement accuracy and reliability

Eastron SEM3-WL excels in extremely accurate measurement of electrical parameters. With an accuracy of active energy ± 1% (class B), voltage and current ± 0.5% and frequency ± 0.2%, it provides reliable data for energy management. The meter operates in a wide voltage range 90 to 300 V AC (L-N) or 156 to 520 V AC (L-L) at a frequency of 50/60 Hz. Data updates occur every 50 ms via RS-485 and 100 ms via Wi-Fi, allowing for accurate and up-to-date power monitoring.

Technical data

• Measurement type: RMS including harmonics in three-phase AC systems (1p2w, 3p4w, 3p3w)
• Nominal voltage: 3× 230 V (L-N) / 400 V (L-L)
• Working voltage range: 90–300 V AC (L-N), 156–520 V AC (L-L)
• Frequency: 50/60 Hz
• Communication 1: RS-485 Modbus RTU (range up to 1000 m)
• Communication 2: Wi-Fi Modbus TCP (802.11 b/g/n), 2.4 GHz band, range up to 30 m indoors and 50 m outdoors
• RS-485 baud rate: 2400 to 115200 bps
• Measuring transformers: CT with adjustable ratios for each phase
• Mounting: on DIN rail, width 1 module

Package contents

• Eastron SEM3-WL electricity meter
• 3 measuring current transformers (CT)