Schneider Altivar ATV320 drive

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
modbus_address	6001	U16	1
modbus_baud_rate	6003	U16	1
modbus_format	6004	U16	1
modbus_timeout	6005	U16	0.1	0.1 s
scan_in1_address	12701	U16	1
scan_in2_address	12702	U16	1
scan_in3_address	12703	U16	1
scan_in4_address	12704	U16	1
scan_in5_address	12705	U16	1
scan_in6_address	12706	U16	1
scan_in7_address	12707	U16	1
scan_in8_address	12708	U16	1
scan_out1_address	12721	U16	1
scan_out2_address	12722	U16	1
scan_out3_address	12723	U16	1
scan_out4_address	12724	U16	1
scan_out5_address	12725	U16	1
scan_out6_address	12726	U16	1
scan_out7_address	12727	U16	1
scan_out8_address	12728	U16	1
com_scan_in1_val	12741	U16	1
com_scan_in2_val	12742	U16	1
com_scan_in3_val	12743	U16	1
com_scan_in4_val	12744	U16	1
com_scan_in5_val	12745	U16	1
com_scan_in6_val	12746	U16	1
com_scan_in7_val	12747	U16	1
com_scan_in8_val	12748	U16	1
com_scan_out1_val	12761	U16	1
com_scan_out2_val	12762	U16	1
com_scan_out3_val	12763	U16	1
com_scan_out4_val	12764	U16	1
com_scan_out5_val	12765	U16	1
com_scan_out6_val	12766	U16	1
com_scan_out7_val	12767	U16	1
com_scan_out8_val	12768	U16	1
mdb_frame_nb	6011	U16	1
mb_net_crc_errors	6010	U16	1
switching_frequency	3102	U16	0.1	0.1 kHz
maximum_output_frequency	3103	U16	0.1	0.1 Hz
high_speed	3104	U16	0.1	0.1 Hz
low_speed	3105	U16	0.1	0.1 Hz
acceleration	9001	U16	0.1	0.1 s
deceleration	9002	U16	0.1	0.1 s

link settings as documented (unverified): RTU; default 19200 8E1; FC 03,06,16,23,43,08; The modification of communication parameters is taken into account after a power cycle of the drive.

bench facts as documented (unverified)

terminals	RJ45
A/B polarity	Yes (Common), connected to the protective earth ground at one or more points of the bus
termination	One 120 Ohm 0.25 W resistor in series with 1 nF 10 V capacitor
connector	RJ45
shield/ground	Shielded cable with 1 twisted pair and at least a third conductor
wiring notes	Bus polarization: One 450...650 Ohm pull-down resistor at 5 V (650 Ohm recommended) and one 450...650 Ohm pull-down resistor at the common (650 Ohm recommended).
max registers/read	63
response timeout	10000 ms
broadcast	supported
protocol notes	Maximum write registers (FC16) is 61 words. FC23 supports max 20 words write, 20 words read.
identification notes	Supports Read Device Identification (FC43/14) returning VendorName (00 hex), ProductCode (01 hex), MajorMinorRevision (02 hex), and ProductName (03 hex).
FC 43 device ID	supported
doc revision	NVE41308.01

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

When running Modbus as a client on a motor drive like ATV320, there is a mismatch in the number of registers since Zephyr uses a function with floating-point extension for register addresses above 5000, which the ATV320 does not support, causing a mismatch in the expected number of registers (Zephyr expects 4 bytes, ATV320 expects 2 bytes). [source]
The ATV320 does not support reading input registers (Modbus command 4), so holding registers (Modbus command 3) must be used instead. [source]
When communicating with the ATV320 via Modbus TCP, the Unit ID on the client side must match the address of the drive (default of 255 may not work). [source]
confirmed: Baud rates [4800, 9600, 19200, 38400] with default 19200 — confirmed by the ATV320 Modbus Serial Link Manual (NVE41308) and parameter overview
confirmed: Supported Modbus functions [3, 6, 16, 23, 43, 8] — confirmed by the ATV320 Modbus Serial Link Manual (NVE41308) which lists Read Holding Registers (03), Write One Output Word (06), Write Multiple Registers (16), Read/write Multiple Registers (23), Read Device Identification (43/14), and Diagnostics (08)
confirmed: Maximum read registers is 63 words, maximum write registers (FC16) is 61 words, and FC23 supports max 20 words write, 20 words read — confirmed by the ATV320 Modbus Serial Link Manual (NVE41308) under 'Supported Modbus Functions'
confirmed: Bus polarization: One 450...650 Ohm pull-down resistor at 5 V (650 Ohm recommended) and one 450...650 Ohm pull-down resistor at the common (650 Ohm recommended) — confirmed by the ATV320 Modbus Serial Link Manual (NVE41308) under 'Schematic Diagram'
confirmed: Line terminator: One 120 Ohm 0.25 W resistor in series with 1 nF 10 V capacitor — confirmed by the ATV320 Modbus Serial Link Manual (NVE41308) under 'Schematic Diagram'
confirmed: Register addresses: modbus_address @ 6001, modbus_baud_rate @ 6003, modbus_format @ 6004, modbus_timeout @ 6005, scan_in1_address @ 12701, scan_out1_address @ 12721, com_scan_in1_val @ 12741, com_scan_out1_val @ 12761, mdb_frame_nb @ 6011, mb_net_crc_errors @ 6010, switching_frequency @ 3102, maximum_output_frequency @ 3103 — confirmed by the ATV320 Modbus Serial Link Manual (NVE41308) and ATV320 Communication Parameters Guide

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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