verified connector library

Daikin DCOM-LT/MB Modbus interface (split/Sky Air/Altherma)

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.

pointaddress (0-based)typescaleunit
leaving_water_main_heating_setpoint1I161°C
leaving_water_main_cooling_setpoint2I161°C
operation_mode_holding3I161
space_heating_cooling_on_off4I161
room_thermostat_control_heating_setpoint6I161°C
room_thermostat_control_cooling_setpoint7I161°C
quiet_mode_operation9I161
dhw_reheat_setpoint10I161°C
dhw_reheat_on_off12I161
dhw_booster_mode_on_off13I161
weather_dependent_mode53I161
weather_dependent_mode_lwt_heating_setpoint_offset54I161°C
weather_dependent_mode_lwt_cooling_setpoint_offset55I161°C
unit_error21I161
unit_error_code22U161
unit_error_sub_code23I161
circulation_pump_running30I161
compressor_run31I161
booster_heater_run32I161
disinfection_operation33I161
defrost_startup35I161
hot_start36I161
three_way_valve37I161
operation_mode_input38I161
leaving_water_temperature_pre_phe40I160.01°C
leaving_water_temperature_pre_buh41I160.01°C
return_water_temperature42I160.01°C
domestic_hot_water_temperature43I160.01°C
outside_air_temperature44I160.01°C
liquid_refrigerant_temperature45I160.01°C
flow_rate49I160.01l/min
remocon_room_temperature50I160.01°C

link settings as documented (unverified): RTU; default 9600 8N1; FC 03,04,06,16; Modbus RTU over RS485 2-wire

⚠ The operation of the product in smart-grid applications must be according to EN60730-1:2011 and must not override the operation of any type 2 action controls nor interfere with any protective function of the control — Starkest reads only; we never write a control register.

bench facts as documented (unverified)
terminalsCSA 0.5 to 2.5mm2, Torque 0.5Nm
A/B polarityPower terminals are polarity independent. 0V and +V can be wired to either terminal.
terminationRS485 termination is not required for normal operation. The DCOM RS485 transceiver has internal failsafe biasing.
connectorPA 6.6 UL94-V0
shield/groundTerminal 'C' must be connected to all other RS485 Common terminals using the drain wire. The shield should only be earthed at one location.
wiring notesDimensions 110 x 88 x 32 mm, Weight 80g, Enclosure PC ABS UL94-V0
max registers/read64
sentinel values32767: Register Unsupported, 32766: Register Unavailable, 32765: Wait for value
protocol notesIf the DCOM is timed out or synchronising with the Altherma master, values will return Wait for value until the value is loaded.
powerRegulated 15-24VDC, 80mA
environmentStorage: -10..60ºC, Operating: 0..55ºC, Humidity: 0-90% Non-condensing
certificationsEMC EN60730-1:2011, Safety EN60730-1:2011
doc revision534-252-A3

generated by gemini:gemini-3.5-flash · harvested from https://www.daikin.eu/content/dam/document-library/installation-manuals/ctrl/bms/dcom-lt-mb/DCOM-LT-MB_reference%20and%20installation%20manual_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.

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.