Eliwell ID 985 refrigeration controller

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 confirmed at the hardware-verified rung and at no rung below it.

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
set_point	6178	I16	0.1
operating_differential	6146	U16	0.1
max_set_point	6180	I16	0.1
min_set_point	6182	I16	0.1
end_of_defrost_temperature	6150	I16	0.1
end_of_defrost_temperature_2nd_evap	6366	I16	0.1
evaporator_fan_shutdown_temperature	6154	I16	0.1
evaporator_fan_startup_temperature	6156	I16	0.1
analogue_input_1	8504	I16	0.1
analogue_input_2	8506	I16	0.1
analogue_input_3	8508	I16	0.1
analogue_input_1_control	8510	I16	0.1
analogue_input_2_control	8512	I16	0.1
analogue_input_3_control	8514	I16	0.1
status_digital_inputs	9009	U16	1
alarms_1	8814	U16	1
alarms_2	8815	U16	1
controller_status	8818	U16	1
relay_status	8763	U16	1

link settings as documented (unverified): RTU; default 9600 8N1; unit ID 1; FC 03,16,43; The baud rate must be set to 9600 bauds. Parity is configurable via parameter PtY (default none), and stop bits via parameter StP (default 1b).

bench facts as documented (unverified)

terminals	5-path connector TTL cable (30cm)
connector	5-path connector TTL cable
shield/ground	shielded and twisted (e.g.: Belden cable model 8762)
wiring notes	Bus Adapter BA150 used for RS485 connection.
max registers/read	60
broadcast	supported
protocol notes	A maximum of 60 consecutive registers can be read or written. Parameters belonging to two different non-consecutive blocks cannot be read using a single command.
identification notes	Device ID fields can be read using Modbus command 43: Field 0 (Manufacturer ID = 'Invensys'), Field 1 (Instrument model ID = '0028_0402'), Field 2 (Instrument version ID = '00E2_0001').
FC 43 device ID	supported
doc revision	2005/03/0

field reports — community-sourced, unverified (checked 2026-06-11)

confirmed: The baud rate must be set to 9600 bauds. Parity is configurable via parameter PtY (default none), and stop bits via parameter StP (default 1b). — confirmed by Eliwell ID 985/E LX Modbus Serial Communication Protocol manual
confirmed: Device ID fields can be read using Modbus command 43: Field 0 (Manufacturer ID = 'Invensys'), Field 1 (Instrument model ID = '0028_0402'), Field 2 (Instrument version ID = '00E2_0001'). — confirmed by Eliwell ID 985/E LX Modbus Serial Communication Protocol manual
confirmed: set_point @ 6178, operating_differential @ 6146, max_set_point @ 6180, min_set_point @ 6182, end_of_defrost_temperature @ 6150, end_of_defrost_temperature_2nd_evap @ 6366, evaporator_fan_shutdown_temperature @ 6154, evaporator_fan_startup_temperature @ 6156, analogue_input_1 @ 8504, analogue_input_2 @ 8506, analogue_input_3 @ 8508, analogue_input_1_control @ 8510, analogue_input_2_control @ 8512, analogue_input_3_control @ 8514, status_digital_inputs @ 9009, alarms_1 @ 8814, alarms_2 @ 8815, controller_status @ 8818, relay_status @ 8763 — confirmed by Eliwell ID 985/E LX Modbus Serial Communication Protocol manual

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.

If your device isn't here, upload its register map. Generation is free, and the connector keeps the rung it earns under testing.

To prove a connector against your own device, order hardware verification. If it doesn't verify, you don't pay.

Platform builders can license the verified library: machine-readable maps, the firmware matrix, API access.