Daikin VRV Modbus interface EKMBDXB

Register map(s) for this device, each at the trust rung it earned. Addresses are 0-based as on the wire; word order and scaling are only confirmed at the hardware-verified rung.

interop-verified

Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.

point	address (0-based)	type	scale	unit
unit_1_00_on_off_status	2000	U16	1
unit_1_00_operation_status	2001	U16	1
unit_1_00_room_temperature_set_point_read	2002	I16	0.1	°C
unit_1_00_room_temperature	2004	I16	0.1	°C
unit_1_00_leaving_water_set_point_heating_read	2800	I16	0.1	°C
unit_1_00_leaving_water_set_point_cooling_read	2801	I16	0.1	°C
unit_1_00_error_code	3600	U16	1
central_forced_off	1000	U16	1
unit_1_00_on_off_command	2000	U16	1
unit_1_00_operation_mode_setting	2001	U16	1
unit_1_00_room_temperature_set_point_write	2002	I16	0.1	°C
unit_1_00_leaving_water_set_point_heating_write	2400	I16	0.1	°C
unit_1_00_leaving_water_set_point_cooling_write	2401	I16	0.1	°C
unit_1_00_domestic_hot_water_storage_set_point_write	2402	I16	0.1	°C
unit_1_00_user_interface_lock	2800	U16	1	°C

link settings as documented (unverified): RTU; default 9600 8E1; FC 03,04,06,16; Silent internal time: 5ms at 9600bps, 2.5ms at 19200bps. Response time is Silent Interval Time + 20ms.

⚠ The number of control commands per indoor unit is limited to 7000 per year. — Starkest reads only; we never write a control register.

bench facts as documented (unverified)

terminals	X3M (RS-485), F1/F2 (DIII-net), X1M (Power supply)
A/B polarity	A+, B-
termination	SS2 On = 120 Ohm, SS3 On = 100 Ohm, SS1 not used. Factory default is 0 Ohm (SS2=Off & SS3=Off)
connector	Terminal strips
shield/ground	Protective earth
wiring notes	BMS RS485 (2 wire, max 500m), DIII net (F1F2) maximum 64 indoor units and maximum 10 outdoors
max registers/read	32
response timeout	25 ms
inter-frame delay	5 ms
broadcast	supported
protocol notes	The number of control commands per indoor unit is limited to 7000 per year.
power	220 – 240 VAC 50/60 Hz
environment	Temp range 0 till 60°C, Indoor installation, IP X0
doc revision	4P642495-1A– 2022.02

generated by gemini:gemini-3.5-flash · harvested from https://www.daikin-ce.com/content/dam/document-library/Installer-reference-guide/ac/vrv/ekmbdxb/EKMBDXB_Design%20guide_4PEN642495-1A_English.pdf (Daikin); manual-faithful — the document's claims, panel risk: ELEVATED — panel is not confident; proved interop-verified on 2026-06-10 · recorded 2026-06-10

The trust ladder

Each rung states what it proved and what it did not. Gray until proven; green is earned by hardware only.

generated — A prompt produced it. Unproven — anyone can regenerate this.
structure-verified — Decode path is structurally sound (addresses, widths, finite values). Does NOT prove word order or scaling.
interop-verified — Read + decoded cleanly over a real network vs an independent third-party Modbus test server (transport and framing; reads are remapped into the server's register window, so the map's own addresses are NOT exercised). Does NOT prove word order/scaling against the actual device.
simulator-verified — Decoded correctly against a protocol emulator seeded with known-true values — catches word-order/scaling errors vs the emulator, not the physical device.
hardware-verified x1 — Matched a real device with operator-attested readings as ground truth — the only rung that confirms word order + scaling on the wire.

Have a device that isn't here? Upload its register map — generation is free, and the connector earns its rung by being proven, not claimed.

Need it proven on your own device? Hardware verification — if it doesn't verify, you don't pay.

Building a platform? License the verified library — machine-readable maps, firmware matrix, API access.