Overview

Direct-Connect Precision. Streamlined DIN-Rail Deployment.

Industrial-Grade 3-Phase Energy Metering, Simplified.

The KEYPLUS SEM3250 is an industrial-grade three-phase direct-connect DIN-rail smart electricity meter engineered for commercial sub-metering, renewable energy systems, and high-density electrical panels. Supporting up to 80A/100A direct input without external current transformers (CTs), it delivers Class 1.0 accuracy, four-quadrant bidirectional metering, and full-spectrum parameter tracking over RS485 Modbus-RTU.

Pain Points & Challenge

Eliminate Installation Bottlenecks & Sub-Metering Disputes

Complex External CT Wiring & Bulky Footprints: Traditional CT setups take hours to wire, clutter cabinet interiors, and risk measurement failures from wiring or ratio configuration errors. The SEM3250 eliminates external CTs through direct connection up to 100A on a standard 35mm DIN rail.
Unauthorized Tampering & Reverse Power Disputes: Unsealed enclosures and untracked solar backfeeding lead to unbilled power usage. The SEM3250 features an ultrasonic permanently welded casing alongside bidirectional Import/Export kWh tracking for tamper-proof revenue protection.

Key Capabilities & Benefits

100A Direct-Connect Architecture

Feature: High-gauge direct wiring terminals supporting up to 80A/100A continuous current.
Advantage: Bypasses secondary current transformer wiring harnesses and eliminates ratio-setting missteps entirely.
Benefit: Slashes panel installation labor costs by more than 50% and accelerates electrical commissioning timelines.

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Bi-Directional Multi-Parameter Measurement

Feature: Four-quadrant bidirectional metering covering kWh, kVArh, kW, kVAr, kVA, PF, Hz, max demand (dmd), and real-time V/A.
Advantage: Accurately distinguishes clean renewable generation (solar/storage) from utility grid import while capturing power factor inefficiencies.
Benefit: Guarantees granular tenant billing, regulatory compliance reporting, and actionable data for corporate carbon-reduction initiatives.

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Industrial Ultrasonic Sealing & RS485 Modbus-RTU

Feature: Permanently sealed ultrasonic welded enclosure paired with isolated RS485 Modbus-RTU and optical pulse (SO) outputs.
Advantage: Mechanically prevents unauthorized physical tampering while offering an open, robust communication standard daisy-chainable up to 1200 meters.
Benefit: Ensures revenue-grade data integrity and allows drop-in integration with the KEYPLUS AIoT Platform, BMS, or third-party SCADA systems.

Ecosystem Integration

The Core Hardware Layer for KEYPLUS AIoT Energy Management

The SEM3250 connects effortlessly with the KEYPLUS G30 3-in-1 IoT Gateway. By converting field Modbus registers into secure MQTT/HTTPS cloud feeds, facility managers gain access to centralized real-time dashboards, automated sub-billing, and immediate overload or phase-abnormality alerts across commercial towers, student housing, and industrial manufacturing plants.

Technical Specifications

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Model Number	SEM3250
Product Type	Three-Phase Multifunctional DIN-Rail Energy Meter
Wiring Configuration	3-Phase 4-Wire (3P4W) / 3-Phase 3-Wire (3P3W) Compatible
Rated / Maximum Current	Direct Input: Up to 80A / 100A (No external CT required)
Accuracy Class	Active Energy: Class 1.0 (IEC 62053-21)
Operating Voltage Range	3×230/400V AC (±20%)
Measurement Parameters	kWh, kVArh, kW, kVAr, kVA, PF, Hz, Demand (dmd), V, A
Energy Flow Direction	Bi-directional Metering (Import & Export / Solar & Grid)
Pulse Output	1 Active Energy Optical Pulse Output (SO)
Communication Interface	RS485 (Half-duplex, 2-wire)
Communication Protocol	Modbus-RTU (Baud rate configurable: 1200–19200 bps)
Mounting Standard	35mm Standard DIN-Rail (EN 50022)
Housing Construction	Ultrasonic welded sealed casing (Anti-tampering, non-disassemblable)
Ingress Protection	IP20 (IEC 60529)
Power Consumption	< 2W / 10VA per phase
Operating Temperature	-25°C to +55°C

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Compact three-phase direct-connect DIN-rail smart electricity meter featuring bidirectional metering, multi-parameter tracking, and RS485 Modbus-RTU for high-precision sub-metering.

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