Schneider Altistart 48 (ATS48) soft starter

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	unit
drivecom_control_register	400	U16	1
extended_control_register	402	U16	1
drivecom_status_register	458	U16	1
extended_status_register	459	U16	1
extended_status_register_2	460	U16	1
nominal_motor_current	4026	U16	0.1
limiting_current	4039	U16	1
acceleration_ramp_time	4043	U16	1
deceleration_ramp_time	4044	U16	1
line_voltage	4055	U16	1	V
motor_current	4062	U16	0.1
motor_torque	4063	U16	1
motor_thermal_state	4064	U16	1
phase_rotation_direction	4065	U16	1
state_of_logic_io	4066	U16	1
cos_phi	4067	U16	0.01
operating_time_since_last_reset	4068	U16	1
image_of_analog_output_ao	4070	U16	0.002
active_power_percent	4072	U16	1
active_power_kw	4073	U16	1
power_consumption	4074	U16	1
product_operating_time	4075	U16	1
last_fault_detected	4200	U16	1

link settings as documented (unverified): RTU; default 19200 8N1; unit ID 0; FC 03,04,06,16,65; Address 0 is used for broadcast or behaves as if configured on all addresses 1 to 31 if configured as 0. Addresses 126 and 127 are privileged.

⚠ This type of use invalidates the starter warranty (referring to LII: All protection disabled on LI3). — Starkest reads only; we never write a control register.

bench facts as documented (unverified)

terminals	RJ45 connector
termination	120 Ohm + 1 nF recommended at both ends
connector	RJ45
shield/ground	connect the cable shielding to the ground of each device
wiring notes	Each ATS48 integrates two 4.7 kohm pulldown resistors. Up to 27 starters can be connected if master has 4.7 kohm pulldown resistors, up to 18 if master has 470 ohm.
max registers/read	30
broadcast	supported
protocol notes	The end of the frame is detected if silent for >= 3 characters.
firmware register	W4501
identification notes	Identification service (code 65) can be used to obtain manufacturer name, product name, product reference, software version, and software upgrade index.
FC 43 device ID	not supported
doc revision	04/2013

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

Depending on the Modbus master's 0-based vs 1-based addressing configuration, an off-by-one offset may occur, requiring commands like the fault reset to be written to register 401 instead of 400. [source]
When reading motor current (W4062), some Modbus masters may read unexpected values (such as 32768 at 0A and 33024 at 24A) due to byte-swapping issues, which require a byte swap to resolve to correct values (e.g., 1 and 24). [source]
confirmed: Baud rates [4800, 9600, 19200], default baud 19200, and RTU framing — confirmed by Altistart 48 Modbus Protocol User Manual
confirmed: Each ATS48 integrates two 4.7 kohm pulldown resistors, allowing up to 27 starters if the master has 4.7 kohm pulldown resistors, or up to 18 if the master has 470 ohm — confirmed by RS485 Bus Wiring and Connections Guide
confirmed: LII inhibits all protection and invalidates the starter warranty — confirmed by Altistart 48 Telemecanique User Manual
confirmed: Register map addresses (e.g., drivecom_control_register @ 400, drivecom_status_register @ 458, nominal_motor_current @ 4026, motor_current @ 4062) — confirmed by ATV31-ATS48 Profibus DP Expander Guide and Device Templates Reference 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.