Eliwell ID 985 refrigeration controller

Register map(s) for this device, with a note of how far each has been checked. Addresses are 0-based, as on the wire. Scale and byte order are confirmed only at the hardware-verified rung.

coherence-checked

Round-trips through a real Modbus stack with no overlapping addresses and a word-order-sensitive codec — the map is internally coherent and wire-decodable. Does NOT prove byte-order or scaling match a real device: the emulator is seeded from the map's own types, so a uniformly wrong byte-order still round-trips. Only hardware-verified confirms byte-order/scale on the wire.

point	address (0-based)	type	scale
Operating differential	6146	U16	1
Set point offset	6148	I16	1
End of defrost temperature	6150	I16	1
Compressor output activation/deactivation time before defrosting	6152	I16	1
Evaporator fan shut-down temperature	6154	I16	1
Evaporator fan start-up temperature	6156	I16	1
Evaporator fan operating differential.	6158	U16	1
alarm differential	6160	U16	1
Temperature alarm exclusion time after defrost cycle	6162	U16	1
Cell probe calibration	6164	I16	1
Calibration of evaporator probe	6166	I16	1
Calibration of probe	6168	I16	1
Minimum value that can be displayed	6170	I16	1
Maximum value that can be displayed	6172	I16	1
Configurability and polarity digital input 1	6174	I16	1
Map code	6176	U16	1
Set point	6178	I16	1
Maximum settable Set point value	6180	I16	1
Minimum settable Set point value	6182	I16	1
Maximum alarm threshold	6184	I16	1
Minimum alarm threshold	6186	I16	1
Alarm set point for 3rd probe	6196	I16	1
Alarm differential 3rd probe	6198	I16	1
Configurability and polarity digital input 2	6200	I16	1
End of defrost temperature 2nd evaporator	6366	I16	1
Condenser fan activation set point	6370	I16	1
Condenser fan operating differential.	6372	I16	1
Minimum compressor output activation time	6715	U16	1
Maximum compressor output activation time	6716	U16	1
load switching off enabled when door switch is switched on	6717	U16	1
Delay in enabling digital inputs	6718	U16	1
Compressor output ON time if control probe faulty	6719	U16	1
Compressor output OFF time if control probe faulty	6720	U16	1
Delay in activating compressor output after start-up.	6721	U16	1
Delay in activating compressor output after shut-down.	6722	U16	1
Delay between two consecutive switch-ons of compressor output	6723	U16	1
Output in activating output after power-on	6724	U16	1
Type of defrost	6725	U16	1
Unit of measurement for defrost times	6726	U16	1
Unit of measurement for duration of defrosting	6727	U16	1
Defrosting time count mode	6728	U16	1
Delay in activating defrost cycle after start-up	6729	U16	1
Defrost time out	6730	U16	1
Defrost activation request after power-on	6731	U16	1
Time before defrosting during which the compressor output is not activated	6732	U16	1
FSt parameter mode (absolute or relative)	6733	U16	1
Delay in enabling evaporator fans after defrost cycle	6734	U16	1
Dripping time	6735	U16	1
Exclusion of evaporator fans during defrost cycle	6736	U16	1
Status of evaporator fans when compressor output OFF	6737	U16	1
Status of evaporator fans when door is open	6738	U16	1
Delay in shut down of evaporator fans after compressor is disabled	6739	U16	1
Time evaporator fans are ON in duty cycle mode	6740	U16	1
Time evaporator fans are OFF in duty cycle mode	6741	U16	1
Device address	6742	U16	1
Family address	6743	U16	1
HAL and LAL parameter modes (absolute or relative)	6744	U16	1
alarm excluded at power on	6745	U16	1
High and low temperature alarm exclusion time after door is closed	6746	U16	1
Alarm exclusion time when door is open	6747	U16	1
Temperature alarm signal delay time	6748	U16	1
Alarm signal for defrost ended timed out	6749	U16	1
External alarm disables controllers	6750	U16	1
Polarity of alarm output	6751	U16	1
Keyboard lock enabled	6753	U16	1
Display with decimal point	6754	U16	1
Intervention of calibration	6755	U16	1
Locked Resources at end of defrosting	6756	U16	1
Display of fundamental state	6757	U16	1
Time for activation of functions from keyboard	6758	U16	1
Digital output 1 configurability	6759	U16	1
Digital output 2 configurability	6760	U16	1
Digital output 3 configurability	6761	U16	1
Digital output 4 configurability	6762	U16	1
UP button configurability	6764	U16	1
DOWN button configurability	6765	U16	1
ESC button configurability	6766	U16	1
inversion of ST1 with ST2 enabled	6767	U16	1
Presence of cell probe	6768	U16	1
Presence of evaporator probe	6769	U16	1
Presence of 3rd probe	6770	U16	1
Interval between defrosts	6771	U16	1
Probe enabled for temperature alarm signalling (probe 1 and/or 3)	6776	U16	1
Time out for display lock after end of defrosting	6777	U16	1
Aux/light button or Digital Input active when instrument is off	6778	U16	1
Operating mode on stand-by	6779	U16	1
Light relay enable from door switch	6780	U16	1
Delay in switching off of light relay after door is closed	6781	U16	1
switching off of cell light button-enabled during delay set in parameter dLt	6782	U16	1
Password 1 value	6783	U16	1
Password 2 value	6784	U16	1
Selection of NTC/PTC type of analogue input	6785	U16	1
°C or °F selection	6786	U16	1
Hours of start of 1st daily defrost	6788	U16	1
Hours of start of 2nd daily defrost	6789	U16	1
Hours of start of 3rd daily defrost	6790	U16	1
Hours of start of 4th daily defrost	6791	U16	1
Hours of start of 5th daily defrost	6792	U16	1
Hours of start of 6th daily defrost	6793	U16	1
Hours of start of 7th daily defrost	6794	U16	1
Hours of start of 8th daily defrost	6795	U16	1
Minutes of start of 1st daily defrost	6796	U16	1
Minutes of start of 2nd daily defrost	6797	U16	1
Minutes of start of 3rd daily defrost	6798	U16	1
Minutes of start of 4th daily defrost	6799	U16	1
Minutes of start of 5th daily defrost	6800	U16	1
Minutes of start of 6th daily defrost	6801	U16	1
Minutes of start of 7th daily defrost	6802	U16	1
Minutes of start of 8th daily defrost	6803	U16	1
Hours of start of 1st festive defrost	6804	U16	1
Hours of start of 2nd festive defrost	6805	U16	1
Hours of start of 3rd festive defrost	6806	U16	1
Hours of start of 4th festive defrost	6807	U16	1
Hours of start of 5th festive defrost	6808	U16	1
Hours of start of 6th festive defrost	6809	U16	1
Hours of start of 7th festive defrost	6810	U16	1
Hours of start of 8th festive defrost	6811	U16	1
Minutes of start of 1st festive defrost	6812	U16	1
Minutes of start of 2nd festive defrost	6813	U16	1
Minutes of start of 3rd festive defrost	6814	U16	1
Minutes of start of 4th festive defrost	6815	U16	1
Minutes of start of 5th festive defrost	6816	U16	1
Minutes of start of 6th festive defrost	6817	U16	1
Minutes of start of 7th festive defrost	6818	U16	1
Minutes of start of 8th festive defrost	6819	U16	1
Enables functions during events on 1st day	6820	U16	1
Enables functions during events on 2nd day	6821	U16	1
Enables functions during events on 3rd day	6822	U16	1
Enables functions during events on 4th day	6823	U16	1
Enables functions during events on 5th day	6824	U16	1
Enables functions during events on 6th day	6825	U16	1
Enables functions during events on 7th day	6826	U16	1
Enables functions during events every day	6827	U16	1
Duration of event 1st day	6828	U16	1
Duration of event 2nd day	6829	U16	1
Duration of event 3rd day	6830	U16	1
Duration of event 4th day	6831	U16	1
Duration of event 5th day	6832	U16	1
Duration of event 6th day	6833	U16	1
Duration of event 7th day	6834	U16	1
Duration of daily event	6835	U16	1
Enables daily or holiday defrosting 1st day	6836	U16	1
Enables daily or holiday defrosting 2nd day	6837	U16	1
Enables daily or holiday defrosting 3rd day	6838	U16	1
Enables daily or holiday defrosting 4th day	6839	U16	1
Enables daily or holiday defrosting 5th day	6840	U16	1
Enables daily or holiday defrosting 6th day	6841	U16	1
Enables daily or holiday defrosting 7th day	6842	U16	1
Hour of start of event 1st day	6844	U16	1
Hour of start of event 2nd day	6845	U16	1
Hour of start of event 3rd day	6846	U16	1
Hour of start of event 4th day	6847	U16	1
Hour of start of event 5th day	6848	U16	1
Hour of start of event 6th day	6849	U16	1
Hour of start of event 7th day	6850	U16	1
Hour of start of event every day	6851	U16	1
minutes of start of event 1st day	6852	U16	1
minutes of start of event 2nd day	6853	U16	1
minutes of start of event 3rd day	6854	U16	1
minutes of start of event 4th day	6855	U16	1
minutes of start of event 5th day	6856	U16	1
minutes of start of event 6th day	6857	U16	1
minutes of start of event 7th day	6858	U16	1
Minutes of start of event every day	6859	U16	1
Selection of Master, Slave, Echo	6860	U16	1
Number of Slaves in network(refers to Master)	6861	U16	1
Presence of local Echoes referring to single slave	6862	U16	1
Simultaneous or sequential defrosting	6863	U16	1
Distributed display (refers to slave)	6864	U16	1
Activation of network functions	6865	U16	1
Locked Resources at end of defrosting	6866	U16	1
Presence of RTC	6867	U16	1
Defrost start-up mode for applications with two evaporators	6876	U16	1
Defrost time out 2nd evaporator	6877	U16	1
Number of errors allowed per maximum/minimum pressure switch input	6880	U16	1
Minimum/maximum pressure switch error count time	6881	U16	1
Condenser fan start-up delay after defrosting	6886	U16	1
exclusion of condenser fans during defrosting	6887	U16	1
Display on eco	6888	U16	1
FORCED behaviour from digital input	6889	U16	1
enables forced behaviour from digital input	6890	U16	1
delay in enabling compressor after activation of digital input	6891	U16	1
delay in enabling fans after activation of digital input	6892	U16	1
Modbus Parity Bit	6893	U16	1
Modbus Stop Bit	6894	U16	1
Analogue input 1	8504	I16	1
Analogue input 2	8506	I16	1
Analogue input 3	8508	I16	1
Analogue input 1 (control) 1	8510	I16	1
Analogue input 2 (control) 1	8512	I16	1
Analogue input 3 (control) 1	8514	I16	1
Command enabling timeout from serial.	8548	U16	1
Status Word 8763	8763	U16	1
Control Word 8801	8801	U16	1
Control Word 8802	8802	U16	1
Status Word 8814	8814	U16	1
Status Word 8815	8815	U16	1
Status Word 8818	8818	U16	1
Status Word 8823	8823	U16	1
Status Word 8826	8826	U16	1
Status Word 9009	9009	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.
coherence-checked — Round-trips through a real Modbus stack with no overlapping addresses and a word-order-sensitive codec — the map is internally coherent and wire-decodable. Does NOT prove byte-order or scaling match a real device: the emulator is seeded from the map's own types, so a uniformly wrong byte-order still round-trips. Only hardware-verified confirms byte-order/scale on the wire.
hardware-verified (software-key) x1 — Matched a real device with operator-attested readings as ground truth — the only rung that confirms word order + scaling on the wire.

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