Systemair Topvex SX/TX/SR/TR air handling unit

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 only confirmed at the hardware-verified rung.

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
std_objs1_ai1_supply_temp_output	1	I16	0.1
std_objs1_ai2_exhaust_air_temp_output	2	I16	0.1
std_objs1_ai3_frost_protection_temp_output	3	I16	0.1
std_objs1_ai4_out_door_temp_output	4	I16	0.1
q_ana_in_ai1	5	I16	0.1
q_ana_in_ai2	6	I16	0.1
q_ana_in_ai3	7	I16	0.1
q_ana_in_ai4	8	I16	0.1
std_objs1_ao1_heating_output	9	I16	0.1
std_objs1_ao2_cooling_output	10	I16	0.1
std_objs1_ao3_rotating_speed_output	11	I16	0.1
q_ana_out_aq1	12	I16	0.1	V
q_ana_out_aq2	13	I16	0.1	V
q_ana_out_aq3	14	I16	0.1	V
q_ana_out_aq4	15	I16	0.1	V
q_ana_out_aq5	16	I16	0.1	V
ala_data_filter_alarm_status	50	U16	1
ala_data_alarm_fan_motor_status	51	U16	1
ala_data_overheat_status	52	U16	1
ala_data_exchanger_rotating_alarm_status	53	U16	1
ala_data_alarm_frost_prot_status	54	U16	1
ala_data_fire_alarm_status	55	U16	1
ala_data_sensor_alarm_supply_temp_status	57	U16	1
ala_data_sensor_alarm_exhaust_temp_status	58	U16	1
ala_data_sensor_alarm_frost_temp_status	59	U16	1
ala_data_sensor_alarm_out_door_temp_status	60	U16	1
ala_data_internal_battery_error_status	61	U16	1
vpac1_unit_type	1	U16	1
vpac1_unit_mode	2	U16	1
vpac1_regulation	3	U16	1
vpac1_unit_off_low	4	U16	1
vpac1_fan_speed_choice	5	U16	1
vpac1_filter_alarm_mod_bus	6	U16	1
vpac1_supply_temp_mod_bus	7	U16	1
vpac1_cooling	8	U16	1
vpac1_cool_recycling	9	U16	1
vpac1_heat_battery_type	10	U16	1
std_objs1_do4_exchanger_select	11	U16	1
std_objs1_ao1_heating_select	12	U16	1	V
std_objs1_ao2_cooling_select	13	U16	1	V
std_objs1_ao3_rotating_speed_select	14	U16	1	V
vpac1_ao1_man_input	15	I16	0.1	V
vpac1_ao2_man_input	16	I16	0.1	V
vpac1_ao3_man_input	17	I16	0.1	V
vpac1_fan_speed_high_set_p	18	I16	1	%
vpac1_fan_speed_medium_set_p	19	I16	1	%
vpac1_fan_speed_low_set_p	20	I16	1	%
vpac1_set_point_m20	21	I16	1	°C
vpac1_set_point_m15	22	I16	1	°C
vpac1_min_supply_temp	23	I16	1	°C
vpac1_max_supply_temp	24	I16	1	°C
vpac1_unit_p_gain	25	I16	1
vpac1_unit_i_time	26	I16	1
vpac1_unit_cascade_p_gain	27	I16	1
vpac1_unit_cascade_i_time	28	I16	1
vpac1_time_extension_set_point	29	I16	1
vpac1_fan_speed_choice_forced	31	U16	1
vpac1_night_cool_outdoor_day	32	I16	1	°C
vpac1_night_cool_outdoor_high_night	33	I16	1	°C
vpac1_night_cool_outdoor_low_night	34	I16	1	°C
vpac1_night_cool_room_limit	35	I16	1	°C
std_objs1_ao4_rotating_speed_eaf_select	36	U16	1
std_objs1_ao5_bypass_select	37	U16	1

link settings as documented (unverified): baud 9600; FC 01,02,03,04,05,06,15,16; The modbus master must wait for a minimum of 3.5 charactertimes (4ms at 9600 bps) between two messages. When the modbus master communicate with more than one controller on the same communication line (RS485), the modbus master must wait for a minimum of 14 charactertimes (16ms at 9600bps) between the answer and the first question for the next controller.

bench facts as documented (unverified)

wiring notes	RS485 communication line
max registers/read	47
inter-frame delay	4 ms
broadcast	not supported
protocol notes	In the controller there is a limit of 10 fast communications in every half minute, the other communications will have a delayed answer of approximately 1 second.
identification notes	The address of the controller is always as default PLA=254 and ELA=30.
doc revision	11-12-05 A002

generated by gemini:gemini-3.5-flash · harvested from https://www.planetaklimata.com.ua/instr/Systemair/MODBUS_for_Systemair_Topvex_SX_TX_SR_TR_User_manual_Eng.pdf (Systemair); manual-faithful — the document's claims, panel risk: ELEVATED — panel is not confident; proved interop-verified on 2026-06-11 · recorded 2026-06-11

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.

Have a device that isn't here? Upload its register map — generation is free, and the connector earns its rung by being proven, not claimed.

Need it proven on your own device? Hardware verification — if it doesn't verify, you don't pay.

Building a platform? License the verified library — machine-readable maps, firmware matrix, API access.