Mitsubishi Ecodan FTC4/FTC5/FTC6 (needs MelcoBEMS MINI A1M)

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
system_on_off	25	U16	1
operating_mode_dhw	27	U16	1
ac_mode_zone_1	28	U16	1
ac_mode_zone_2	29	U16	1
set_tank_water_temperature_signed	30	I16	0.01	°C
set_tank_water_temperature	31	U16	0.01	°C
hc_thermostat_target_temperature_zone_1_signed	32	I16	0.01	°C
hc_thermostat_target_temperature_zone_1	33	U16	0.01	°C
hc_thermostat_target_temperature_zone_2_signed	34	I16	0.01	°C
hc_thermostat_target_temperature_zone_2	35	U16	0.01	°C
force_dhw	37	U16	1	Hz
holiday	38	U16	1	Hz
dhw_on_prohibit	39	U16	1
heating_on_prohibit_zone_1	40	U16	1	°C
cooling_on_prohibit_zone_1	41	U16	1	°C
heating_on_prohibit_zone_2	42	U16	1	°C
cooling_on_prohibit_zone_2	43	U16	1	°C
thermostat_target_temperature_zone_1_signed	54	I16	0.01	°C
thermostat_target_temperature_zone_1	55	U16	0.01	°C
thermostat_target_temperature_zone_2_signed	56	I16	0.01	°C
thermostat_target_temperature_zone_2	57	U16	0.01	°C
hc_control_type	58	U16	1
defrost	67	U16	1
residual_heat_removal	68	U16	1
refrigerant_error_info	69	U16	1
status_of_heating	72	U16	1
heat_pump_frequency_master	73	U16	1	Hz
heat_source_status	80	U16	1
temperature_setpoint_zone_1_signed	81	I16	0.01	°C
temperature_setpoint_zone_1	82	U16	0.01	°C
temperature_setpoint_zone_2_signed	83	I16	0.01	°C
temperature_setpoint_zone_2	84	U16	0.01	°C
flow_temperature_setpoint_zone_1_signed	85	I16	0.01	°C
flow_temperature_setpoint_zone_1	86	U16	0.01	°C
flow_temperature_setpoint_zone_2_signed	87	I16	0.01	°C
flow_temperature_setpoint_zone_2	88	U16	0.01	°C
legionella_temperature_setpoint_signed	89	I16	0.01	°C
legionella_temperature_setpoint	90	U16	0.01	°C
dhw_temperature_drop_signed	91	I16	0.1	°C
dhw_temperature_drop	92	U16	0.1	°C
room_temperature_zone_1_signed	93	I16	0.01	°C
room_temperature_zone_1	94	U16	0.01	°C
room_temperature_zone_2_signed	95	I16	0.01	°C
room_temperature_zone_2	96	U16	0.01	°C
refrigerant_liquid_temperature_signed	97	I16	0.01	°C
refrigerant_liquid_temperature	98	U16	0.01	°C
outdoor_ambient_temperature_signed	99	I16	0.1	°C
outdoor_ambient_temperature	100	U16	0.1	°C
flow_temperature_signed	101	I16	0.01	°C
flow_temperature	102	U16	0.01	°C
return_temperature_signed	103	I16	0.01	°C
return_temperature	104	U16	0.01	°C
tank_water_temperature_signed	105	I16	0.01	°C
tank_water_temperature	106	U16	0.01	°C
flow_temperature_zone_1_signed	107	I16	0.01	°C
flow_temperature_zone_1	108	U16	0.01	°C
return_temperature_zone_1_signed	109	I16	0.01	°C
return_temperature_zone_1	110	U16	0.01	°C
flow_temperature_zone_2_signed	111	I16	0.01	°C
flow_temperature_zone_2	112	U16	0.01	°C
return_temperature_zone_2_signed	113	I16	0.01	°C
return_temperature_zone_2	114	U16	0.01	°C
boiler_flow_temperature_signed	115	I16	0.01	°C
boiler_flow_temperature	116	U16	0.01	°C
boiler_return_temperature_signed	117	I16	0.01	°C
boiler_return_temperature	118	U16	0.01	°C
heat_pump_run_time_hours	136	U16	1
boiler_on_off	144	U16	1
booster_heater_1_on_off	145	U16	1
booster_heater_2_on_off	146	U16	1
water_pump_1_on_off	149	U16	1
water_pump_2_on_off	150	U16	1
water_pump_3_on_off	151	U16	1
three_way_valve_on_off	152	U16	1
two_way_valve_2_on_off	153	U16	1
mixing_valve_step	154	U16	1
capacity_of_supplying_electricity	269	U16	0.1
last_measured_heating_energy_consumption_kwh	282	U16	1
last_measured_heating_energy_consumption_wh	283	U16	10
last_measured_cooling_energy_consumption_kwh	284	U16	1
last_measured_cooling_energy_consumption_wh	285	U16	10
last_measured_dhw_energy_consumption_kwh	286	U16	1
last_measured_dhw_energy_consumption_wh	287	U16	10
last_measured_total_energy_consumption_kwh	288	U16	1
last_measured_heating_energy_produced_kwh	292	U16	1
last_measured_heating_energy_produced_wh	293	U16	10
last_measured_cooling_energy_produced_kwh	294	U16	1
last_measured_cooling_energy_produced_wh	295	U16	10
last_measured_dhw_energy_produced_kwh	296	U16	1
last_measured_dhw_energy_produced_wh	297	U16	10
last_measured_total_energy_produced_kwh	298	U16	1
flow_rate	299	U16	1
mix_tank_water_temp_signed	385	I16	0.01
mix_tank_water_temp	386	U16	0.01
condensing_temp_signed	387	I16	0.01
condensing_temp	388	U16	0.01
flow_rate_2	394	U16	1
water_pump_4_on_off	395	U16	1
two_way_valve_2a_on_off	396	U16	1
two_way_valve_2b_on_off	397	U16	1

link settings as documented (unverified): RTU; baud 1200/2400/4800/9600/14400/19200/28800/38400/56000/57600/115200; FC 01,02,03,04,05,06,15,16; Some BMS controllers can only read Modbus Holding Registers, so the MelcoBEMS MINI (A1M) also exposes all Discrete, Coil and Input Registers as Holding Registers.

bench facts as documented (unverified)

terminals	RS-485
firmware register	40011
doc revision	1.0.5
firmware applicability	3.0.25

generated by gemini:gemini-3.5-flash · harvested from https://www.mitsubishitechinfo.ca/sites/default/files/AG_MelcoBEMS%20MINI%20(A1M)%20-%20FTC%20Modbus%20Register%20Tables%20V1.0.5_fw3.0.25.pdf (Mitsubishi Electric); manual-faithful — the document's claims, panel risk: LOW — panel concurs, no field disagreements; 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.