YTL DEM3A202 – 100 A Three-Phase Energy Meter with RS485 and Modbus RTU
The YTL DEM3A202 is a compact and versatile direct-connected three-phase energy meter designed for accurate energy monitoring in modern electrical installations. With a maximum current rating of 100 A, DIN-rail mounting and RS485 communication, it is suitable for building automation, industrial applications and electrical sub-metering.
Modbus RTU support allows measured values to be read by compatible energy monitoring systems, PLCs and other equipment supporting the protocol. The specified communication refresh time is no more than 75 ms, making the meter suitable for applications where timely measurement updates are important.
Flexible energy monitoring
The DEM3A202 measures active and reactive energy, as well as electrical parameters such as power, power factor and harmonics. Multiple energy calculation modes provide flexibility in installations where imported and exported energy flows need to be monitored.
The backlit LCD display provides convenient local access to readings. Additional features include a pulse LED, wiring checks, self-diagnostics and configurable alarms for electrical measurements.
Key features
- Direct-connected three-phase metering up to 100 A.
- RS485 communication supporting Modbus RTU and DL/T 645-2007.
- Class 0.5 active energy accuracy.
- Supports both 3-wire (3P3W, delta) and 4-wire (3P4W) systems.
- Measures energy, power, power factor and harmonics.
- Forward, reverse, absolute-value, algebraic-sum and net-energy calculation modes.
- External tariff-switching input.
- Backlit LCD display and pulse LED.
- Compact 54 mm wide DIN-rail design.
- Operating temperature from -40°C to +70°C.
Technical specifications
- Model: DEM3A202
- Type: Direct-connected three-phase energy meter
- Mounting: DIN rail
- Wiring system: 3P3W (delta) / 3P4W
- Rated voltage: 3 × 120/208 V to 3 × 230/400 V
- Voltage tolerance: 0.8–1.15 × Un
- Frequency: 50/60 Hz
- Basic current (Ib): 5 A
- Minimum current (Imin): 0.15 A (MID) / 0.25 A (IEC)
- Maximum current (Imax): 100 A
- Power consumption: ≤ 2 W / 10 VA
- Pulse constant: 1000 imp/kWh
- Voltage accuracy: ±0.5%
- Current accuracy: ±0.5%
- Frequency accuracy: ±0.5%
- Active power accuracy: ±0.5%
- Reactive power accuracy: ±1%
- Active energy accuracy: Class 0.5
- Reactive energy accuracy: Class 1
- Communication: Bidirectional RS485
- Protocols: Modbus RTU and DL/T 645-2007
- Communication address: 1–247
- Baud rates: 9.6 / 19.2 / 38.4 / 57.6 / 115.2 kbps
- Parity: None / odd / even
- Specified communication refresh time: ≤ 75 ms
- Display: Backlit LCD, 500 ms refresh
- Additional functions: Diagnostics, configurable alarms, wiring check, local firmware upgrade and runtime-hour counter
- Tariff function: External tariff switching; default two-tariff configuration
- Operating temperature: -40°C to +70°C
- Ingress protection: IP20
- Overvoltage category: OVC III
- Protection class: Class II
- Rated impulse withstand voltage: 6 kV
- Width: 54 mm
Communication and tariff control
The RS485 interface enables connection to compatible energy monitoring and automation systems. Always verify that the communication settings, register mapping and protocol versions match the meter documentation.
The meter supports external tariff switching. It does not have an internal real-time clock, battery or built-in time-of-use schedule. Tariff switching must therefore be managed externally.
Typical applications
- Sub-metering in commercial and residential buildings.
- Industrial energy monitoring and production facilities.
- Electrical distribution boards and power distribution systems.
- Integration with compatible Modbus-based control systems.
- Energy-flow monitoring in solar PV and energy storage installations.
- Energy monitoring for EV charging infrastructure and technical installations.
Installation
The meter has an IP20 rating and must be installed inside a suitable electrical enclosure. The manufacturer specifies an IP51 enclosure for indoor use and IP54 for outdoor use. Installation and wiring must be carried out by suitably qualified personnel in accordance with applicable regulations and the manufacturer's wiring diagram.
