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  3. EKMBDXB7V1

Daikin EKMBDXB7V1 Modbus register map

Modbus RTU interface for up to 64 indoor unit groups on a Daikin DIII-net (VRV, Sky Air, hydrobox, ventilation)

  • Official
  • 4,363 registers
  • Modbus RTU
  • Revision 2 · 2026-10-18

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.

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Communication

Protocol
Modbus RTU
Unit ID
1
Serial
9600 8E1 · 9600 baud, 8 data bits, even parity, 1 stop bit
Byte / word order
ABCD · bytes big-endian, words high first
Addresses
0-based
Max read
32 registers per request

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

Map

Registers
1217 holding registers, 3146 input registers
Groups
65
Translation tables
9
Revision
2 · 2026-10-18
Added
()
File
maps/daikin/ekmbdxb7v1.mbmap.json · 747 KB · history
SHA-256
0c4d576c25b12fe93808348318f4930057fde43cb8716ba4d11218700749bfb8
Manufacturer
daikin.com

Sources and notes

  • Design guide Modbus Interface DIII EKMBDXB7V1 · version 4P642495-1A (2022.02)
    chapter 2 (communication) and chapter 3 (input and holding registers)

Source: Daikin, "Design guide Modbus Interface DIII EKMBDXB7V1", 4P642495-1A (2022.02)

  • Each DIII address 1-00 to 4-15 has its own block of registers; index n runs from 0 (1-00) to 63 (4-15) and the register groups are named after the DIII address.
  • Communication: DS1-2 off = 9600, on = 19200 baud; DS1-3/DS1-4 select parity even 1 stop (default), odd 1 stop, none 2 stop or none 1 stop. The slave address (1-15) is set with DS2.
  • Supported function codes: 03, 04, 06 and 16. At most 32 registers per read and 30 per write.
  • Holding registers do not follow the real state of the units: they only take the actual values when a unit is detected. Before changing one field, copy the current values from the matching input registers into the holding register so the other fields are not changed.
  • Which registers have a meaning depends on the unit type (indoor unit, ventilation, hydrobox); check the capability registers first.
  • The set point range bytes are 8-bit signed values in °C; they are read here as unsigned bytes, so values above 127 are negative (value - 256).
AreaAddressNameTypeAccessUnitScaleDescription
IR 0 bool bit 0 R 0 = busy (detecting units), 1 = ready
IR 0 bool bit 1 R
IR 1 uint16 R Bit 0-15 = DIII address 1-00 to 1-15, 1 = connected
IR 2 uint16 R Bit 0-15 = DIII address 2-00 to 2-15, 1 = connected
IR 3 uint16 R Bit 0-15 = DIII address 3-00 to 3-15, 1 = connected
IR 4 uint16 R Bit 0-15 = DIII address 4-00 to 4-15, 1 = connected
IR 5 uint16 R Bit 0-15 = DIII address 1-00 to 1-15, 1 = communication error
IR 6 uint16 R Bit 0-15 = DIII address 2-00 to 2-15, 1 = communication error
IR 7 uint16 R Bit 0-15 = DIII address 3-00 to 3-15, 1 = communication error
IR 8 uint16 R Bit 0-15 = DIII address 4-00 to 4-15, 1 = communication error
HR 1000 bool bit 0 RW 1 = forced off for all units; only works when no other DIII central device is present
IR 1000 bool bit 15 R
IR 1000 uint16 bits 12–14 R
IR 1000 bool bit 11 R
IR 1000 uint16 bits 8–10 R
IR 1000 bool bit 4 R
IR 1000 bool bit 3 R
IR 1000 bool bit 2 R
IR 1000 bool bit 1 R
IR 1000 bool bit 0 R
IR 1001 uint16 bits 8–15 R °C
IR 1001 uint16 bits 0–7 R °C
IR 1002 uint16 bits 8–15 R °C
IR 1002 uint16 bits 0–7 R °C
IR 1400 bool bit 5 R Hydrobox
IR 1400 bool bit 4 R Hydrobox
IR 1400 bool bit 2 R Hydrobox
IR 1400 bool bit 1 R Hydrobox
IR 1401 uint16 bits 8–15 R °C
IR 1401 uint16 bits 0–7 R °C
IR 1402 uint16 bits 8–15 R °C
IR 1402 uint16 bits 0–7 R °C
IR 2000 uint16 bits 12–14 R 0-7, meaning depends on the fan speed steps: fixed 5 = H; 2 steps 0 Auto, 1 L, 5 H; 3 steps 0 Auto, 1 L, 3 M, 5 H; 5 steps 0 Auto, 1 LL, 2 L, 3 M, 4 H, 5 HH; ventilation (VAM) 3 L, 7 H
IR 2000 uint16 bits 8–10 R
IR 2000 bool bit 7 R
IR 2000 bool bit 6 R
IR 2000 bool bit 5 R
IR 2000 bool bit 3 R
IR 2000 bool bit 2 R
IR 2000 bool bit 0 R
IR 2001 uint16 bits 14–15 R
IR 2001 bool bit 13 R
IR 2001 uint16 bits 9–11 R
IR 2001 uint16 bits 4–7 R 0 = off, 1-15 = on
IR 2001 uint16 bits 0–3 R
IR 2002 int16 R °C ×0.1
IR 2004 int16 R °C ×0.1 Suction (return air) temperature
IR 2800 int16 R °C ×0.1 Hydrobox
IR 2801 int16 R °C ×0.1 Hydrobox
IR 2802 uint16 bits 8–15 R °C Hydrobox
IR 2802 bool bit 2 R
IR 2802 bool bit 1 R
IR 2802 bool bit 0 R
IR 2803 uint16 bits 6–7 R Ventilation units
IR 3600 string[1] R Two ASCII characters, "00" = no error
IR 3601 uint16 bits 12–15 R
IR 3601 bool bit 10 R
IR 3601 bool bit 9 R
IR 3601 bool bit 8 R
IR 3601 uint16 bits 0–5 R
HR 2000 uint16 bits 12–14 RW Same values as the fan speed input; only applied when the fan control flag is 6
HR 2000 uint16 bits 8–10 RW Only applied when the fan control flag is 6
HR 2000 uint16 bits 4–7 RW
HR 2000 uint16 bit 0 RW
HR 2001 uint16 bits 4–7 RW Write 15 to reset the filter sign, then write 0
HR 2001 uint16 bits 0–3 RW
HR 2002 int16 RW °C ×0.1
HR 2400 int16 RW °C ×0.1 Hydrobox
HR 2401 int16 RW °C ×0.1 Hydrobox
HR 2402 uint16 bits 8–15 RW °C Hydrobox
HR 2402 uint16 bit 2 RW
HR 2402 uint16 bit 0 RW
HR 2403 uint16 bits 6–7 RW
HR 2800 uint16 bit 5 RW
HR 2800 uint16 bit 4 RW
HR 2800 uint16 bit 3 RW
HR 2800 uint16 bit 2 RW
HR 2800 uint16 bit 1 RW
HR 2800 uint16 bit 0 RW
IR 1003 bool bit 15 R
IR 1003 uint16 bits 12–14 R
IR 1003 bool bit 11 R
IR 1003 uint16 bits 8–10 R
IR 1003 bool bit 4 R
IR 1003 bool bit 3 R
IR 1003 bool bit 2 R
IR 1003 bool bit 1 R
IR 1003 bool bit 0 R
IR 1004 uint16 bits 8–15 R °C
IR 1004 uint16 bits 0–7 R °C
IR 1005 uint16 bits 8–15 R °C
IR 1005 uint16 bits 0–7 R °C
IR 1404 bool bit 5 R Hydrobox
IR 1404 bool bit 4 R Hydrobox
IR 1404 bool bit 2 R Hydrobox
IR 1404 bool bit 1 R Hydrobox
IR 1405 uint16 bits 8–15 R °C
IR 1405 uint16 bits 0–7 R °C
IR 1406 uint16 bits 8–15 R °C
IR 1406 uint16 bits 0–7 R °C

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