Lovato Electric DMG800 Modbus register map

Sources and notes

• DMG series - Modbus communication protocol · version I317 I GB 02_22, 2022-02-07
  tables 2 and 3

Source: Lovato Electric, DMG series Modbus communication protocol, I317 I GB 02_22

• Addresses are those of the manual; the address sent in the request is one less (address_base 1).
• Function 03 and 04 both read the measurements. 32- and 64-bit values are sent high word first.
• Serial and Ethernet communication need an EXM expansion module (RS-232, RS-485, USB or Ethernet).
• The model is reported by function 17 (Report Slave ID): type code 0xB4.
• Max (HI), min (LO), average and max demand values, harmonics, I/O and setup parameters (tables 4-8 of the manual) are not listed here.
• Tested on a DMG800 read over a Modbus TCP gateway, November 2026; 72 of 102 registers read in the first test. Checked: voltages, currents, power (current and power agree: 666 VA / 230.14 V = 2.89 A), power factor, THD, neutral current, the 32-bit and 64-bit energy counters, counters, hour meters, clock, power resolution (0.01 W) and the word order (big). Frequency read 50040, so its scale is 0.001 (50.04 Hz), not 0.01 as this map had before.
• The 64-bit energy counters and the four tariffs (6944-7063) all exist on that meter and read correctly in requests of 10, 20 and 80 registers (the tariffs were all 0, no tariff in use; the 64-bit counters match the 32-bit ones). A single request for all 120 registers (6944-7063) was refused with illegal data address, so max_read_registers is set to 80, the longest request tested.
• Cos phi (0x002C-0x0030), N-earth voltage, neutral current measured and the THD of N-earth voltage and of N current (0x0066-0x006C) are marked for the DMG900 only in the manual and were removed from this map. A DMG800 still answered the cos phi registers, but the values did not match its power factor and power (L1: 590.4 W and -306 var give 0.888, the register read 0.9931).