Thermokon FTA54+ RH/temp sensor

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.

structure-verified

Decode path is structurally sound (addresses, widths, finite values). Does NOT prove word order or scaling.

point	address (0-based)	type	scale	unit
UNI: Firmware	0	I16	1
UNI: Device Location	1	I16	1
UNI: Offset temperature	5	I16	0.01	K
UNI: Offset rel. humidity	6	I16	0.01	%
USE: Offset temperature	100	I16	0.1	K
USE: Offset rel. humidity	101	I16	0.1	%rH
USE: Unit system	400	I16	1
USE: Firmware version	503	I16	1
UNI: Relative humidity	585	I16	0.1	%
UNI: Temperature	587	I16	0.01	°C
UNI: Temperature	588	I16	0.01	°F

link settings as documented (unverified): RTU/ASCII; default 9600 8E1; unit ID 1; When using ASCII mode, parity must be set to EVEN or ODD. 'No Parity' (no) is not available in ASCII mode. Register addressing mode (UNI or USE) is selectable via DIP switch 2.6.

⚠ The product should only be used for the intended application. Unauthorised modifications are prohibited! The product must not be used in relation with any equipment that in case of a failure may threaten, directly or indirectly, human health or life or result in danger to human beings, animals or assets. Ensure all power is disconnected before installing. Do not connect to live/operating equipment. — Starkest reads only; we never write a control register.

bench facts as documented (unverified)

terminals	removable plug-in terminal, max. 14AWG
A/B polarity	In case of reversed polarity at one field device, a supply voltage short-circuit would be caused by that device.
connector	removable plug-in terminal
wiring notes	Cable entry Flextherm M20, for wire max. Ø=0.18..0.35 in., removable
protocol notes	Register compatibility to USE (Valid from firmware version 1.4, Jan. 2020). Via dipswitch 2.6 it is possible to change between the previous register addressing of the UNI-Modbus board to a USE compatible register assignment.
firmware register	0 (Variant 1) or 503 (Variant 2)
identification notes	Firmware version is available at register 0 in UNI-Modbus mode or register 503 in USE-Modbus mode.
power	15..24 V = (±10%) (or 24 V ~ (±10%))* SELV, max. 0,7 W (24 V =) \| 1,8 VA (24 V ~)
environment	Ambient condition -4..+158 °F, short term condensation. IP65 according to EN 60529
accuracy	Accuracy temperature ±0,3 K (typ. at 70 °F), Accuracy humidity ±2% between 10..90% rH (typ. at 70 °F)
certifications	CE
doc revision	05/21/2026 • A160
firmware applicability	Valid from firmware version 1.4, Jan. 2020

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

confirmed: Baud rates [9600, 19200, 38400, 57600] and default baud rate 9600 — confirmed by Thermokon FTA54+ Basic RS485 Modbus Datasheet
confirmed: Default Unit ID is 1 — confirmed by Thermokon FTA54+ Basic RS485 Modbus Datasheet
confirmed: ASCII mode requires EVEN or ODD parity, No Parity is not available in ASCII mode — confirmed by Thermokon FTA54+ Basic RS485 Modbus Datasheet
confirmed: Register addressing mode (UNI or USE) is selectable via DIP switch 2.6 — confirmed by Thermokon FTA54+ Basic RS485 Modbus Datasheet
confirmed: Accuracy temperature ±0,3 K (typ. at 70 °F), Accuracy humidity ±2% between 10..90% rH (typ. at 70 °F) — confirmed by Thermokon FTA54+ Basic RS485 Modbus Datasheet (US version)
confirmed: Power supply 15..24 V = (±10%) or 24 V ~ (±10%) SELV, max. 0,7 W (24 V =) | 1,8 VA (24 V ~) — confirmed by Thermokon FTA54+ Basic RS485 Modbus Datasheet
confirmed: Ambient condition -4..+158 °F, short term condensation, IP65 according to EN 60529 — confirmed by Thermokon FTA54+ Basic RS485 Modbus Datasheet
confirmed: Reversed polarity at one field device causes a supply voltage short-circuit — confirmed by Thermokon FTA54+ Basic RS485 Modbus Datasheet

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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