AutomationDirect SOLO SL4848 temp 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	unit
process_value	4096	I16	0.1	°C or °F
set_point_value	4097	I16	0.1	0.1 °C or °F
input_range_high	4098	I16	0.1
input_range_low	4099	I16	0.1
input_type	4100	U16	1
control_mode	4101	U16	1
heating_cooling	4102	U16	1
output_1_heating_cooling_period	4103	U16	1	s
output_2_period	4104	U16	1	s
proportion_band	4105	U16	0.1
integral_time	4106	U16	1
derivative_time	4107	U16	1
integral_offset	4108	U16	0.1	%
pd_control_offset	4109	U16	0.1	%
proportion_band_coefficient	4110	U16	0.01
dead_band	4111	I16	1
output_1_hysteresis	4112	U16	1
output_2_hysteresis	4113	U16	1
output_1_level	4114	U16	0.1	%
output_2_level	4115	U16	0.1	%
analog_high_adjustment	4116	U16	1	uA or mV
analog_low_adjustment	4117	U16	1	uA or mV
pv_offset	4118	I16	1
decimal_point_position	4119	U16	1
pid_parameter_group	4124	U16	1
target_sv	4125	I16	0.1
alarm_1	4128	U16	1
alarm_2	4129	U16	1
alarm_3	4130	U16	1
system_alarm	4131	U16	1
alarm_1_high_limit	4132	I16	1
alarm_1_low_limit	4133	I16	1
alarm_2_high_limit	4134	I16	1
alarm_2_low_limit	4135	I16	1
alarm_3_high_limit	4136	I16	1
alarm_3_low_limit	4137	I16	1
led_status	4138	U16	1
pushbutton_status	4139	U16	1
lock_mode	4140	U16	1
starting_ramp_soak_pattern	4144	U16	1
step_time_in_seconds	4146	U16	1	s
step_time_in_minutes	4147	U16	1	min
current_step_number	4148	U16	1
current_pattern_number	4149	U16	1

link settings as documented (unverified): RTU/ASCII; default 9600 8E1; FC 01,02,03,05,06,16; All of the SOLO controllers have a 2-wire RS-485 serial communication port.

bench facts as documented (unverified)

terminals	2-wire
connector	RS-485 serial communication port
max registers/read	8
protocol notes	Maximum limit is read of eight registers for FC03, and write of eight registers for FC16.
firmware register	4143

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

The On-Line Configuration parameter (CoSH / P3-12) must be manually set to ON via the front panel keypad before the controller will accept any Modbus write commands (FC06/FC16); otherwise, it rejects writes with a Modbus exception code. [source]
The SoloSoft configuration software window is clipped on widescreen displays (16:9, e.g., 1920x1080) because it calculates window height assuming a 4:3 aspect ratio, making the parameter window taller than the screen and hiding the bottom portion. [source]
Modbus RTU communication fails with Error Code 02 (Illegal Data Address) if the master attempts to read or write registers using incorrect byte/word order or incorrect register offsets (e.g., using address 1 instead of 4097 for Set Point Value). [source]
confirmed: All of the SOLO controllers have a 2-wire RS-485 serial communication port — confirmed by SOLO Temperature Controller User Manual Chapter 7 [8.1.1]
confirmed: Baud rates: 2400, 4800, 9600, 19200, 38400 bps — confirmed by SOLO Temperature Controller User Manual Chapter 7
confirmed: Default baud rate: 9600 — confirmed by SOLO Temperature Controller User Manual Chapter 7
confirmed: Framing: RTU, ASCII — confirmed by SOLO Temperature Controller User Manual Chapter 7
confirmed: Parity: E (Even) — confirmed by SOLO Temperature Controller User Manual Chapter 7
confirmed: Stop bits: 1 — confirmed by SOLO Temperature Controller User Manual Chapter 7
confirmed: Function codes: 1, 2, 3, 5, 6, 16 — confirmed by SOLO Temperature Controller User Manual Chapter 7
confirmed: Maximum limit is read of eight registers for FC03, and write of eight registers for FC16 — confirmed by SOLO Temperature Controller User Manual Chapter 7

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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