Siemens OpenAir GDB/GLB181.1E/MO VAV compact controller

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
setpoint	0	U16	0.01	%
override_control	1	U16	1
actual_position	2	U16	0.01	%
actual_flow_rel	3	U16	0.01	%
actual_flow_abs	4	U16	1	m3/h
actual_pressure	5	U16	0.1	Pa
command	255	U16	1
opening_direction	256	U16	1
adaptive_mode	257	U16	1
operating_mode	258	U16	1
min_position	259	U16	0.01	%
max_position	260	U16	0.01	%
actuator_running_time	261	U16	1	s
vnom	384	U16	1	m3/h
vmin	385	I16	0.01	%
vmax	386	U16	0.01	%
altitude_level	387	U16	1	m
unit_switch	388	U16	1
backup_mode	512	U16	1
backup_position	513	U16	0.01	%
backup_timeout	514	U16	1	s
modbus_address	763	U16	1
baudrate	764	U16	1
transmission_format	765	U16	1
bus_termination	766	U16	1
bus_conf_command	767	U16	1
status	768	U16	1

link settings as documented (unverified): RTU; baud 9600/19200/38400/57600/76800/115200; unit ID 255; FC 03,04,06,16; Default baud rate is Auto. Default transmission format is 1-8-E-1. Maximum of 120 registers within one message.

bench facts as documented (unverified)

terminals	Terminal strip 7-pin, grid 2.00 mm
A/B polarity	Bus + on grey (GY), Bus - on pink (PK), REF on violet (VT)
termination	120 Ohm electronically switchable
connector	Prewired cables (power / communication)
isolation	galvanically separated
wiring notes	Delivered with two prewired cables.
max registers/read	120
protocol notes	Overwriting the bus configuration over bus uses a timeout. If '1 = Load' is not written into Reg 768 within 30 seconds, all values are discarded.
model register	1408
serial register	1283
power	AC 24 V ± 20 % (SELV) or AC 24 V class 2 (US), 50/60 Hz, 1 VA / 0.5 W (holding), 3 VA / 2.5 W (rotating)
environment	Class 3K5, Indoors, 0...50 °C, 5...95 % r. F. (non condensing)
accuracy	Differential pressure sensor: Zero point ± 0.2 Pa, Amplitude ± 4.5 % of the measured value, Drift ± 0.1 Pa / Year
certifications	CE, RCM, UL, cUL
doc revision	A6V10631832_en--_d (2018-04-16)

generated by gemini:gemini-3.5-flash · harvested from https://www.2kshops.com/content/pdf-siemens/GDB181.1E-3%20GLB181.1E-3%20VAV%20compact%20controller.pdf (Siemens); manual-faithful — the document's claims, panel risk: ELEVATED — panel is not confident; proved interop-verified on 2026-06-10 · recorded 2026-06-10

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.