RKI Beacon 3200 gas monitor

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
system_status	0	U16	1
ch_1a_state_status	1	U16	1
ch_1a_reading	19	U16	1
ch_1b_state_status	21	U16	1
ch_1b_reading	39	U16	1
ch_1c_state_status	41	U16	1
ch_1c_reading	59	U16	1
ch_1d_state_status	61	U16	1
ch_1d_reading	79	U16	1
ch_2a_state_status	81	U16	1
ch_2a_reading	99	U16	1
ch_2b_state_status	101	U16	1
ch_2b_reading	119	U16	1
ch_2c_state_status	121	U16	1
ch_2c_reading	139	U16	1
ch_2d_state_status	141	U16	1
ch_2d_reading	159	U16	1

link settings as documented (unverified): RTU/TCP; default 19200 8E?; unit ID 11; FC 03,06; Supports Modbus RTU (2-wire) and Modbus TCP/IP on port 502. Supports up to 32 Modbus detectors without a repeater. Slave ID range is 1 to 247.

bench facts as documented (unverified)

terminals	RS-485 Modbus Terminal Strips (Master and Slave) are located in the lower left corner of the main PCB.
A/B polarity	A is TX/RX+, B is TX/RX-, C is Common
termination	Ground and termination jumpers on board. 120 Ohm, 3/4W termination resistor required for the last T3A/VOC Pro slave device.
connector	Terminal Strips and RJ45 LAN Connector
shield/ground	Field ground stud on the bottom right corner of the main PCB is typically used to connect the shield drain wire.
wiring notes	Supports a max cable length of 4,000 feet with recommended impedance of 120 ohms.
broadcast	supported
protocol notes	When the Beacon 3200 is in any operating menu other than normal operation, the channel registers simply hold their existing values. Once the Beacon 3200 returns to normal operation, the channel registers are updated each second.
identification notes	The warmup screen shows the instrument's firmware version.
power	100V/115V/220V AC, 50/60Hz or 24V DC ± 10%
environment	Indoor or outdoor (Type 4X), 2000m max altitude, -40°C to 40°C ambient, 80% max relative humidity, Overvoltage Category II, Pollution Degree 2. Cannot be mounted in direct sunlight.
certifications	QPS, CSA
doc revision	0

⚠ disputed: Ambient temperature range is -40°C to 40°C — disputed by RKI Instruments website and some manual revisions which state -40°C to 50°C (-40°F to 122°F)

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

Discrepancy in the vendor manual's temperature conversion: one revision lists '-40°C to 50°C (-4°F to 122°F)' and another lists '-40°C to 40°C max (-4°F to 104°F)', incorrectly converting -40°C as -4°F (which is actually -20°C). The official product page lists the correct range as -40°F to 122°F (-40°C to 50°C). [source]
confirmed: Default baud rate is 19200 — confirmed by RKI Beacon 3200 Operator's Manual (Table 13)
confirmed: Default unit ID (Slave ID) is 11 — confirmed by RKI Beacon 3200 Operator's Manual (Table 13)
confirmed: Modbus RTU (2-wire) and Modbus TCP/IP on port 502 are supported — confirmed by RKI Beacon 3200 Operator's Manual (Chapter 13)
confirmed: Modbus polarity is A is TX/RX+, B is TX/RX-, C is Common — confirmed by RKI Beacon 3200 Operator's Manual (Table 8)
confirmed: Warmup screen displays the instrument's firmware version — confirmed by RKI Beacon 3200 Operator's Manual (Chapter 3)
confirmed: Register map matches 0-based offsets (e.g., system_status @ 0, ch_1a_state_status @ 1, ch_1a_reading @ 19) — confirmed by RKI Beacon 3200 Operator's Manual (Chapter 13)

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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