≤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.
DEM1E304 45 A Single-Phase DIN-Rail Energy Meter with M-Bus and TOU
DEM1E304 is a single-phase, direct-connected DIN-rail energy meter for 1P2W systems with a maximum current of 45 A and wired M-Bus communication in accordance with EN 13757-3. It is rated 120–230 V with a basic current of 5 A, measures Class 0.5 (Class C) active energy, and operates over −40°C to +70°C. The meter occupies 1P (18 mm) on a standard 35 mm DIN rail and is MID B+D certified by SGS UK. Battery-backed RTC supports four TOU tariffs across eight time periods by default, plus external tariff switching.
DIN-Rail Mounting (1P, 18 mm)
1P2W Direct Connection
MID Certified
MID
45 A Maximum current (Imax)
120–230 V Rated voltage
Class 0.5 (Class C) Active energy accuracy
−40°C to +70°C Operating temperature
Product Highlights
Compact M-Bus Metering with Fast Data Refresh and TOU
Class 0.5 Active Energy Accuracy
Class 0.5 (Class C) active-energy and Class 1 (Class B) reactive-energy measurement in accordance with IEC 62053-21 and IEC 62053-24.
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.
RTC-Based TOU Tariffs
Battery-backed RTC supports four TOU tariffs across eight time periods by default, combined with external dual-tariff switching through a volt-free digital input.
Flexible Energy Calculation
Supports forward + reverse (absolute value), forward − reverse (algebraic sum), forward-only and reverse-only energy calculation modes for different submetering requirements.
Internal Battery and RTC Timekeeping
An internal battery maintains RTC timekeeping through supply interruptions, so tariff switching keeps its schedule without relying on mains power.
Applications
Applications and Selection Guidance
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Explore ApplicationTechnical Specifications
Technical Specifications
| Voltage connection | Direct connection |
| Rated voltage | 120–230 V |
| Voltage tolerance | 0.8 to 1.2 Un |
| Frequency | 50/60 Hz |
| Current connection | Direct connection |
| Basic current (Ib) | 5 A |
| Minimum current (Imin) | 0.15 A (MID) / 0.25 A (IEC) |
| Maximum current (Imax) | 45 A |
| Pulse constant | 1000 imp/kWh |
| Power consumption | ≤2 W / 10 VA |
| Active energy accuracy | Class 0.5 (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 6+2 |
| LCD refresh time | 500 ms |
| Pulse indicator | Red LED |
| Keys | Page / Set |
| IP rating | IP30 |
| OVC (overvoltage category) | Class III |
| Insulation class | Class II |
| Installation | 35 mm DIN rail, 1P (18 mm) |
| Wiring system | Direct connection, 1P2W |
| Dimensions (H × W × D) | 18 mm × 94 mm × 62.4 mm |
| Operating temperature | −40°C to +70°C |
| Relative humidity | ≤95%, non-condensing |
| Altitude | ≤2000 m |
| Rated impulse voltage | 6 kV |
| Standards | IEC 62052-11:2020 / IEC 62053-21:2020 / IEC 62053-24:2020 / EN 50470-3:2022 |
Structure & Dimensions
DEM1E304 Dimensions & Wiring
Dimensions
Wiring
FAQ
Product FAQ
What is DEM1E304?
DEM1E304 is a single-phase, direct-connected DIN-rail energy meter for 1P2W systems with a maximum current of 45 A and wired M-Bus communication in accordance with EN 13757-3. It is rated 120–230 V with a basic current of 5 A, measures Class 0.5 (Class C) active energy, and operates over −40°C to +70°C. The meter occupies 1P (18 mm) on a standard 35 mm DIN rail and is MID B+D certified by SGS UK. Battery-backed RTC supports four TOU tariffs across eight time periods by default, plus external tariff switching.
What communication protocol does it use?
M-Bus in accordance with EN 13757-3, bidirectional, 2400 bps fixed, 8 data bits / 1 stop bit / even parity, address default 1 with a range of 1–250 and broadcast address 25
What is the maximum current?
The maximum current (Imax) is 45 A on a direct connection.
What is the active energy accuracy?
Class 0.5 (Class C) active energy and Class 1 (Class B) reactive energy.
What does the ≤75 ms specification refer to?
The controlled specification states a communication refresh time of ≤75 ms for the M-Bus communication function. End-to-end system performance also depends on concentrator polling and network configuration.
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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