Algodue Elettronica · Energy meter
UEM45 / UEM100 / UEMCT / UEMRGW / UEM2L / UEM4L Modbus register map
Default configuration
- Protocol
- RS485
- Port
- 502
- Unit ID
- 1
- Addressing
- 0-based
- Byte order
- Big endian
- Word order
- High word first
- Baud rate
- 19200
- Parity
- None
- Data bits
- 8
- Stop bits
- 1
This device has an RS-485 interface. Reach it through a Modbus RTU-to-TCP gateway, configured with the factory serial settings above.
Register map
| Address | Count | Name | Type | Unit | Scale | Access |
|---|---|---|---|---|---|---|
| 4096 | 2 | Phase 1 to neutral voltage | Float32 | V | 1 | R |
| 4098 | 2 | Phase 2 to neutral voltage | Float32 | V | 1 | R |
| 4100 | 2 | Phase 3 to neutral voltage | Float32 | V | 1 | R |
| 4102 | 2 | Phase 1 to phase 2 voltage | Float32 | V | 1 | R |
| 4104 | 2 | Phase 2 to phase 3 voltage | Float32 | V | 1 | R |
| 4106 | 2 | Phase 3 to phase 1 voltage | Float32 | V | 1 | R |
| 4108 | 2 | Phase to phase voltage average | Float32 | V | 1 | R |
| 4110 | 2 | Phase 1 current | Float32 | A | 1 | R |
| 4112 | 2 | Phase 2 current | Float32 | A | 1 | R |
| 4114 | 2 | Phase 3 current | Float32 | A | 1 | R |
| 4116 | 2 | Neutral current (calculated) | Float32 | A | 1 | R |
| 4118 | 2 | Phase currents average | Float32 | A | 1 | R |
| 4120 | 2 | Phase 1 power factor | Float32 | - | 1 | R |
| 4122 | 2 | Phase 2 power factor | Float32 | - | 1 | R |
| 4124 | 2 | Phase 3 power factor | Float32 | - | 1 | R |
| 4126 | 2 | System power factor | Float32 | - | 1 | R |
| 4128 | 2 | Phase 1 active power | Float32 | W | 1 | R |
| 4130 | 2 | Phase 2 active power | Float32 | W | 1 | R |
| 4132 | 2 | Phase 3 active power | Float32 | W | 1 | R |
| 4134 | 2 | System active power | Float32 | W | 1 | R |
| 4136 | 2 | Phase 1 apparent power | Float32 | VA | 1 | R |
| 4138 | 2 | Phase 2 apparent power | Float32 | VA | 1 | R |
| 4140 | 2 | Phase 3 apparent power | Float32 | VA | 1 | R |
| 4142 | 2 | System apparent power | Float32 | VA | 1 | R |
| 4144 | 2 | Phase 1 reactive power | Float32 | var | 1 | R |
| 4146 | 2 | Phase 2 reactive power | Float32 | var | 1 | R |
| 4148 | 2 | Phase 3 reactive power | Float32 | var | 1 | R |
| 4150 | 2 | System reactive power | Float32 | var | 1 | R |
| 4152 | 2 | System frequency | Float32 | Hz | 1 | R |
| 4156 | 2 | Phase to neutral voltage average | Float32 | V | 1 | R |
| 4158 | 2 | Phase currents sum | Float32 | A | 1 | R |
| 4160 | 2 | Phase 1 to neutral voltage THD | Float32 | % | 1 | R |
| 4162 | 2 | Phase 2 to neutral voltage THD | Float32 | % | 1 | R |
| 4164 | 2 | Phase 3 to neutral voltage THD | Float32 | % | 1 | R |
| 4168 | 2 | Phase 1 to phase 2 voltage THD | Float32 | % | 1 | R |
| 4170 | 2 | Phase 2 to phase 3 voltage THD | Float32 | % | 1 | R |
| 4176 | 2 | Phase 1 current THD | Float32 | % | 1 | R |
| 4178 | 2 | Phase 2 current THD | Float32 | % | 1 | R |
| 4180 | 2 | Phase 3 current THD | Float32 | % | 1 | R |
| 4184 | 2 | Phase 1 voltage-current angle | Float32 | deg | 1 | R |
| 4186 | 2 | Phase 2 voltage-current angle | Float32 | deg | 1 | R |
| 4188 | 2 | Phase 3 voltage-current angle | Float32 | deg | 1 | R |
| 4190 | 2 | Phase voltage-current angles average | Float32 | deg | 1 | R |
| 4244 | 2 | Phase 1 current demand | Float32 | A | 1 | R |
| 4246 | 2 | Phase 2 current demand | Float32 | A | 1 | R |
| 4248 | 2 | Phase 3 current demand | Float32 | A | 1 | R |
| 4250 | 2 | Neutral current demand | Float32 | A | 1 | R |
| 4256 | 2 | System active power demand | Float32 | W | 1 | R |
| 4258 | 2 | System apparent power demand | Float32 | VA | 1 | R |
| 4260 | 2 | System reactive power demand | Float32 | var | 1 | R |
| 4262 | 2 | Phase 1 current demand MAX | Float32 | A | 1 | R |
| 4264 | 2 | Phase 2 current demand MAX | Float32 | A | 1 | R |
| 4266 | 2 | Phase 3 current demand MAX | Float32 | A | 1 | R |
| 4268 | 2 | Neutral current demand MAX | Float32 | A | 1 | R |
| 4274 | 2 | System active power demand MAX | Float32 | W | 1 | R |
| 4276 | 2 | System apparent power demand MAX | Float32 | VA | 1 | R |
| 4278 | 2 | System reactive power demand MAX | Float32 | var | 1 | R |
| 4352 | 2 | Phase 1 imported active energy | Float32 | Wh | 1 | R |
| 4354 | 2 | Phase 2 imported active energy | Float32 | Wh | 1 | R |
| 4356 | 2 | Phase 3 imported active energy | Float32 | Wh | 1 | R |
| 4358 | 2 | System imported active energy | Float32 | Wh | 1 | R |
| 4360 | 2 | Phase 1 exported active energy | Float32 | Wh | 1 | R |
| 4362 | 2 | Phase 2 exported active energy | Float32 | Wh | 1 | R |
| 4364 | 2 | Phase 3 exported active energy | Float32 | Wh | 1 | R |
| 4366 | 2 | System exported active energy | Float32 | Wh | 1 | R |
| 4432 | 2 | Phase 1 imported reactive energy | Float32 | varh | 1 | R |
| 4434 | 2 | Phase 2 imported reactive energy | Float32 | varh | 1 | R |
| 4436 | 2 | Phase 3 imported reactive energy | Float32 | varh | 1 | R |
| 4438 | 2 | Phase 1 exported reactive energy | Float32 | varh | 1 | R |
| 4440 | 2 | Phase 2 exported reactive energy | Float32 | varh | 1 | R |
| 4442 | 2 | Phase 3 exported reactive energy | Float32 | varh | 1 | R |
| 4444 | 2 | System imported reactive energy | Float32 | varh | 1 | R |
| 4446 | 2 | System exported reactive energy | Float32 | varh | 1 | R |
| 4448 | 2 | System apparent energy | Float32 | VAh | 1 | R |
| 4450 | 2 | Measure hour counter The manual's IEEE column gives 0.1h as the unit of this counter. | Float32 | h | 0.1 | R |
| 5120 | 2 | System imported active energy, partial | Float32 | Wh | 1 | R |
| 5122 | 2 | System exported active energy, partial | Float32 | Wh | 1 | R |
| 5130 | 2 | System apparent energy, partial | Float32 | VAh | 1 | R |
| 5136 | 2 | System imported reactive energy, partial | Float32 | varh | 1 | R |
| 5138 | 2 | System exported reactive energy, partial | Float32 | varh | 1 | R |
| 5140 | 2 | System active energy balance (import - export) | Float32 | Wh | 1 | R |
| 5150 | 2 | System reactive energy balance (import - export) | Float32 | varh | 1 | R |
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Related guides
Notes
Sources: Algodue 'MODBUS Communication Protocol for energy meters with integrated RS485 interface - UEM45, UEM100, UEMCT, UEMRGW, UEM2L, UEM4L series', PROTOCOL MANUAL Ed2505, section 6 'READING Registers (Function code $03)' - https://www.algodue.com/wp-content/uploads/2025/10/NEW-UEM_MODBUS-protocol.pdf - and the UEM2L/UEM4L multilingual manual, wiring chapter 'Default value: 19200 bps' - https://www.algodue.com/wp-content/uploads/2026/05/UEM2L_UEM4L_MultilingualManual.pdf . The protocol manual states each meter is 'preset with a default slave address (01)' and fixes the RTU frame as '1 Start, 8 Bit, None, 1 Stop (8N1)'; the installation manual gives the factory speed, 19200 bps. Only the manual's IEEE-754 float bank is used: the parallel integer bank stores power in three 16-bit registers (24-bit values) that the app's register types cannot express. The float addresses are the manual's IEEE column, used as wire addresses, and the manual's worked conversion example (45AACC00h = 5465.5) shows the high word first, hence HighFirst. Float-bank values are already in engineering units (the 0.001 column belongs to the integer bank), so no scale is applied except on the hour counter. Deliberate omissions: the 24-bit integer bank, the minimum/MAX rows (the model columns mark them N/A for most variants), the phase-rotation and serial/model/status words, the channel 2-4 blocks (multi-load meters repeat the same layout at 4000h/6000h/8000h), the tariff counter blocks and every writable setup register.