≤75 ms Communication Refresh
The controlled specification states an M-Bus communication refresh time of ≤75 ms for applications that require timely meter-side data updates.
DEM3K304 6 A Three-Phase CT-Operated DIN-Rail Energy Meter with M-Bus and TOU
DEM3K304 is a three-phase DIN-rail energy meter for CT/PT-operated metering in 3P4W and 3P3W (Aron) systems, designed for photovoltaic, energy-storage, factory energy-monitoring and secondary-billing applications. It provides Class 0.5S (Class C) active-energy accuracy with CT ratios up to 2000:1 and PT ratios up to 350:1, and communicates over wired M-Bus in accordance with EN 13757-3. The meter mounts on a standard 35 mm DIN rail in three modules and operates over −40°C to +70°C. Battery-backed RTC supports four TOU tariffs across eight time periods by default, combined with external dual-tariff switching.
CT/PT Operated
3P3W (Aron) / 3P4W
MID Certified
MID
54 mm DIN-rail width (3P)
5(6) A CT input rating
2000:1 · 350:1 CT / PT max ratio
−40°C to +70°C Operating temperature
Product Highlights
Fast Data Refresh for CT-operated metering with TOU
Class 0.5S Active Energy Accuracy
Class 0.5S (Class C) active-energy and Class 1 (Class B) reactive-energy measurement in accordance with IEC 62053-22 and IEC 62053-24, holding accuracy from 0.05 A upwards.
M-Bus System Integration
Two-way M-Bus communication in accordance with EN 13757-3, with default address 1, broadcast address 254 and address range 1–250 at 2400 bps (8E1), so the meter connects directly to an existing M-Bus concentrator loop without protocol conversion.
Flexible CT/PT Ratio Configuration
CT ratios up to 2000:1 and PT ratios up to 350:1, with a maximum combined CT × PT ratio of 350000:1, covering low-voltage high-current and medium-voltage metering points with one model.
RTC-Based TOU and Tariff Switching
Battery-backed RTC supports four TOU tariffs across eight time periods by default, together with external dual-tariff switching through a volt-free digital input.
Multiple Energy Calculation Modes
Supports forward + reverse (absolute value), forward − reverse (algebraic sum), forward-only, reverse-only and forward/reverse offset calculation modes for different submetering requirements.
Applications
Applications and Selection Guidance
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Explore ApplicationTechnical Specifications
Technical Specifications
| Voltage connection | Direct connection / PT |
| Rated voltage (3P4W) | 3 × 57.7/100 V – 3 × 230/400 V |
| Rated voltage (3P3W) | 3 × 100 V – 3 × 400 V |
| Voltage tolerance | 0.8 to 1.2 Un |
| Frequency | 50/60 Hz |
| Current connection | CT (external current transformer) |
| Basic current (Ib) | 5 A |
| Minimum current (Imin) | 0.05 A |
| Maximum current (Imax) | 6 A |
| CT ratio | Up to 2000:1 |
| PT ratio | Up to 350:1 |
| CT × PT ratio (max) | 350000:1 |
| Pulse constant | 10000 imp/kWh |
| Power consumption | ≤2 W / 10 VA |
| Active energy accuracy | Class 0.5S (Class C) |
| Reactive energy accuracy | Class 1 (Class B) |
| Voltage accuracy | ±0.5% |
| Current accuracy | ±0.5% |
| Frequency accuracy | ±0.5% |
| Active power accuracy | ±0.5% |
| Reactive power accuracy | ±1% |
| Communication interface | M-Bus |
| Protocol | M-Bus (EN 13757-3) |
| Communication type | Bidirectional |
| Baud rate | 2400 bps (fixed) |
| Frame format | 8 data bits / 1 stop bit / even parity (8E1) |
| M-Bus address | Default 1, broadcast 254, range 1–250 |
| Refresh time | ≤75 ms |
| Display | LCD 5+3 kWh, with automatic unit scaling 5+3 → 6+2 → 7+1 → 8+0 MkWh |
| LCD refresh time | 500 ms |
| Pulse indicator | Red LED |
| Keys | Page / Set |
| IP rating | IP30 (install in an IP54 cabinet outdoors or IP51 cabinet indoors) |
| OVC (overvoltage category) | Class III |
| Insulation class | Class II |
| Rated impulse voltage | 6kV |
| Installation | 35 mm DIN rail, 3P (54 mm) |
| Wiring system | External CT/PT, 3P3W (Aron) / 3P4W |
| Dimensions (H × W × D) | 54 mm × 94 mm × 63 mm |
| Operating temperature | −40°C to +70°C |
| Relative humidity | ≤95%, non-condensing |
| Altitude | ≤2000 m |
| Standards | IEC 62052-11:2020 / IEC 62053-22:2020 / IEC 62053-24:2020 / EN 50470-3:2022 |
Structure & Dimensions
DEM3K304 Dimensions & Wiring
Dimensions
Wiring
FAQ
Product FAQ
What is DEM3K304?
DEM3K304 is a three-phase DIN-rail energy meter for CT/PT-operated metering in 3P4W and 3P3W (Aron) systems, designed for photovoltaic, energy-storage, factory energy-monitoring and secondary-billing applications. It provides Class 0.5S (Class C) active-energy accuracy with CT ratios up to 2000:1 and PT ratios up to 350:1, and communicates over wired M-Bus in accordance with EN 13757-3. The meter mounts on a standard 35 mm DIN rail in three modules and operates over −40°C to +70°C. Battery-backed RTC supports four TOU tariffs across eight time periods by default, combined with external dual-tariff switching.
What connection and wiring does it use?
CT/PT-operated with external current and voltage transformers, supporting 3P4W and 3P3W (Aron) wiring.
What communication protocol does it use?
M-Bus in accordance with EN 13757-3, bidirectional, 2400 bps fixed, 8E1, address default 1 with a range of 1–250 and broadcast address 254.
What is the maximum current?
The CT input is rated 5(6) A. The primary current is set by the CT ratio, which is configurable up to 2000:1.
What is the active energy accuracy?
Class 0.5S (Class C) active energy and Class 1 (Class B) reactive energy.
Does it include RTC and TOU tariffs?
Yes — battery-backed RTC with four TOU tariffs across eight time periods by default, plus external dual-tariff switching.
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