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  3. ND20

Lumel ND20 Modbus register map

1- and 3-phase power network meter with harmonics, 15/30/60 min mean power, relay and analogue outputs, Modbus RTU over RS485

  • Official
  • 372 registers
  • Modbus RTU
  • Revision 1 · 2026-10-18
  • Identity: firmware, serial number

Official: Written from the manufacturer's documentation, but not tested on a device yet. Check the map against the manufacturer's documentation before you write to a live device. Tested it? Report a test.

Download .mbmap.json Raw JSON View on GitHub Suggest a correction Report a problem

Communication

Protocol
Modbus RTU
Unit ID
1default
Serial
9600 8N2 · 9600 baud, 8 data bits, none parity, 2 stop bits
Byte / word order
ABCD · bytes big-endian, words high first
Addresses
0-based
Max read
82 registers per request

Connection values are defaults: the device may be configured differently.

Map

Registers
372 holding registers
Groups
8
Revision
1 · 2026-10-18
Added
()
File
maps/lumel/nd20.mbmap.json · 57 KB · history
SHA-256
5962314e3dd04002500ad43ee7c8a7c6bded83724a0ba033a2ec6d1d239c9c95
Manufacturer
lumel.com.pl

Device identity

What a tool can read to check that this map fits the connected device (SPEC.md section 4.7). Registers with a role are read like any other register.

Registers
RoleRegisterAddressTypeValues
Firmware Program version holding 4053 uint16
Serial number Serial number holding 4051 uint32 ABCD

Sources and notes

Source: Lumel, ND20 power network meter user manual, section 8

  • Measurements are read from the 7000 area: IEEE 754 floats in two registers, bytes in the order 3-2-1-0. The same data is available as 32-bit registers (7500-7786, one address per value) and in the byte order 1-0-3-2 (6000-6573); this map uses the 7000 and 7800 areas.
  • Values the meter cannot give are returned as 1e20 (above range or error) or -1e20 (below range).
  • Which values exist depends on the measurement mode (3Ph/4W, 3Ph/3W or 1Ph/2W). The manual has a column per mode; for 3Ph/3W the per-phase powers, voltages and power factors are not available.
  • Energy is also in registers 4038-4049 as 32-bit integers in units of 100 Wh. The meter returns 1e20 when it cannot give a value; the manual does not say how the integer energy registers behave.
  • Registers 1000-1077 hold the mean power archive (a window of 15 records); they are not listed here.
  • Registers marked with firmware_min 1.09 exist from program version 1.09. Registers 4062-4068 are reserved.
AreaAddressNameTypeAccessUnitScaleDescription
HR 4053 uint16 R ×0.01
HR 4051 uint32 ABCD R
HR 4050 uint16 R
HR 4050 bool bit 15 R
HR 4050 bool bit 14 R
HR 4050 bool bit 13 R
HR 4050 bool bit 12 R
HR 4050 bool bit 11 R
HR 4050 bool bit 10 R
HR 4050 bool bit 7 R
HR 4050 bool bit 6 R
HR 4050 bool bit 5 R
HR 4050 bool bit 4 R
HR 4050 bool bit 3 R
HR 4050 bool bit 2 R
HR 4050 bool bit 1 R
HR 4050 bool bit 0 R
HR 4050 uint16 bits 8–9 R
HR 4061 bool bit 14 R
HR 4061 bool bit 13 R
HR 4061 bool bit 12 R
HR 4061 bool bit 11 R Nature of the reactive power (status register 2)
HR 4061 bool bit 10 R Nature of the reactive power (status register 2)
HR 4061 bool bit 9 R Nature of the reactive power (status register 2)
HR 4061 bool bit 8 R Nature of the reactive power (status register 2)
HR 4061 bool bit 7 R Nature of the reactive power (status register 2)
HR 4061 bool bit 6 R Nature of the reactive power (status register 2)
HR 4061 bool bit 5 R Nature of the reactive power (status register 2)
HR 4061 bool bit 4 R Nature of the reactive power (status register 2)
HR 4061 bool bit 3 R Nature of the reactive power (status register 2)
HR 4061 bool bit 2 R Nature of the reactive power (status register 2)
HR 4061 bool bit 1 R Nature of the reactive power (status register 2)
HR 4061 bool bit 0 R Nature of the reactive power (status register 2)
HR 7000 float32 ABCD R V
HR 7002 float32 ABCD R A
HR 7004 float32 ABCD R W
HR 7006 float32 ABCD R var
HR 7008 float32 ABCD R VA
HR 7010 float32 ABCD R
HR 7012 float32 ABCD R
HR 7014 float32 ABCD R V
HR 7016 float32 ABCD R A
HR 7018 float32 ABCD R W
HR 7020 float32 ABCD R var
HR 7022 float32 ABCD R VA
HR 7024 float32 ABCD R
HR 7026 float32 ABCD R
HR 7028 float32 ABCD R V
HR 7030 float32 ABCD R A
HR 7032 float32 ABCD R W
HR 7034 float32 ABCD R var
HR 7036 float32 ABCD R VA
HR 7038 float32 ABCD R
HR 7040 float32 ABCD R
HR 7042 float32 ABCD R V
HR 7044 float32 ABCD R A
HR 7046 float32 ABCD R W
HR 7048 float32 ABCD R var
HR 7050 float32 ABCD R VA
HR 7052 float32 ABCD R
HR 7054 float32 ABCD R
HR 7056 float32 ABCD R Hz
HR 7058 float32 ABCD R V
HR 7060 float32 ABCD R V
HR 7062 float32 ABCD R V
HR 7064 float32 ABCD R V
HR 7066 float32 ABCD R W
HR 7080 float32 ABCD R
HR 7082 float32 ABCD R
HR 7084 float32 ABCD R
HR 7086 float32 ABCD R
HR 7088 float32 ABCD R °
HR 7090 float32 ABCD R °
HR 7092 float32 ABCD R °
HR 7094 float32 ABCD R A
HR 7068 float32 ABCD R V/%
HR 7070 float32 ABCD R V/%
HR 7072 float32 ABCD R V/%
HR 7074 float32 ABCD R A/%
HR 7076 float32 ABCD R A/%
HR 7078 float32 ABCD R A/%
HR 7096 float32 ABCD R 100 MWh
HR 7098 float32 ABCD R kWh
HR 7100 float32 ABCD R 100 MWh
HR 7102 float32 ABCD R kWh
HR 7104 float32 ABCD R 100 Mvarh
HR 7106 float32 ABCD R kvarh
HR 7108 float32 ABCD R 100 Mvarh
HR 7110 float32 ABCD R kvarh
HR 7112 float32 ABCD R 100 MWh
HR 7114 float32 ABCD R kWh
HR 7116 float32 ABCD R 100 MWh
HR 7118 float32 ABCD R kWh
HR 7120 float32 ABCD R
HR 7122 float32 ABCD R
HR 7124 float32 ABCD R
HR 7126 float32 ABCD R mA
HR 7128 float32 ABCD R V
HR 7130 float32 ABCD R V
HR 7132 float32 ABCD R V

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