Carrier BACnet/Modbus translator

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 confirmed at the hardware-verified rung and at no rung below it.

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
modbus_address	1	U16	1
modbus_baud_rate	2	U16	1
display_units	3	U16	1
pic_bus_number	4096	U16	1
pic_address_number	4097	U16	1
pic_baud_rate	4098	U16	1
time_hour	8192	U16	1
time_minutes	8193	U16	1
time_date_status_bits	8194	U16	1
point_1_val_x1	16384	I16	1
point_2_val_x1	16385	I16	1
point_3_val_x1	16386	I16	1
point_4_val_x1	16387	I16	1
point_5_val_x1	16388	I16	1
point_6_val_x1	16389	I16	1
point_7_val_x1	16390	I16	1
point_8_val_x1	16391	I16	1
point_9_val_x1	16392	I16	1
point_10_val_x1	16393	I16	1
point_1_val_x10	16640	I16	0.1
point_2_val_x10	16641	I16	0.1
point_3_val_x10	16642	I16	0.1
point_4_val_x10	16643	I16	0.1
point_5_val_x10	16644	I16	0.1
point_6_val_x10	16645	I16	0.1
point_7_val_x10	16646	I16	0.1
point_8_val_x10	16647	I16	0.1
point_9_val_x10	16648	I16	0.1
point_10_val_x10	16649	I16	0.1
point_1_val_x100	16896	I16	0.01
point_2_val_x100	16897	I16	0.01
point_3_val_x100	16898	I16	0.01
point_4_val_x100	16899	I16	0.01
point_5_val_x100	16900	I16	0.01
point_6_val_x100	16901	I16	0.01
point_7_val_x100	16902	I16	0.01
point_8_val_x100	16903	I16	0.01
point_9_val_x100	16904	I16	0.01
point_10_val_x100	16905	I16	0.01
point_1_val_x1000	17152	I16	0.001
point_2_val_x1000	17153	I16	0.001
point_3_val_x1000	17154	I16	0.001
point_4_val_x1000	17155	I16	0.001
point_5_val_x1000	17156	I16	0.001
point_6_val_x1000	17157	I16	0.001
point_7_val_x1000	17158	I16	0.001
point_8_val_x1000	17159	I16	0.001
point_9_val_x1000	17160	I16	0.001
point_10_val_x1000	17161	I16	0.001
point_1_status	20480	U16	1
point_2_status	20481	U16	1
point_3_status	20482	U16	1
point_4_status	20483	U16	1
point_5_status	20484	U16	1
point_6_status	20485	U16	1
point_7_status	20486	U16	1
point_8_status	20487	U16	1
point_9_status	20488	U16	1
point_10_status	20489	U16	1
setpoint_1_val_x100	33280	I16	0.01
setpoint_2_val_x100	33281	I16	0.01
setpoint_3_val_x100	33282	I16	0.01
setpoint_4_val_x100	33283	I16	0.01
setpoint_5_val_x100	33284	I16	0.01
setpoint_6_val_x100	33285	I16	0.01
setpoint_7_val_x100	33286	I16	0.01
setpoint_8_val_x100	33287	I16	0.01
setpoint_9_val_x100	33288	I16	0.01
setpoint_10_val_x100	33289	I16	0.01
time_schedule_1_manual_override_hours	36864	U16	1
time_schedule_1_period_1_dow	36865	U16	1
time_schedule_1_period_1_occupied_from	36866	U16	1
time_schedule_1_period_1_occupied_to	36867	U16	1

link settings as documented (unverified): RTU; default 9600 8N1; unit ID 16; FC 03,04,06,16; Default parity is None (0), default stop bits is 1. Flow control default is None (0).

bench facts as documented (unverified)

connector	CCN BACnet/MODBUS connector
wiring notes	Outdoor duty rated
sentinel values	-999.99
environment	Outdoor duty rated
doc revision	808-356 01/05

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

The official Modbus point definition specification has errors in status definitions for specific chiller models (such as 30HXC), causing status values to mismatch. [source]
The translator has a slow 30-second refresh interval for polling CCN points, making it unsuitable for real-time high-demand applications like variable water volume or backpressure control. [source]
The translator's communication port is not fully isolated and has a bare board structure without shielding, leading to a high failure rate in the field. [source]
confirmed: Baud rates [1200, 2400, 4800, 9600, 19200, 38400] and default baud rate of 9600 — confirmed by Carrier Translator Manual 808-356 01/05
confirmed: Default Modbus address of 16 — confirmed by Carrier Translator Manual 808-356 01/05
confirmed: Supported Modbus RTU function codes 3, 4, 6, and 16 — confirmed by Carrier Translator Manual 808-356 01/05
confirmed: Default parity is None (0), default stop bits is 1, and default flow control is None (0) — confirmed by Carrier Translator Manual 808-356 01/05
confirmed: Physical connector (CCN BACnet/MODBUS connector) and outdoor duty rating — confirmed by Carrier Translator Manual 808-356 01/05
confirmed: Unmapped points display a sentinel value of -999.99 — confirmed by Carrier Translator Manual 808-356 01/05
confirmed: Register map addresses (Modbus Address @ 1, Modbus Baud Rate @ 2, Units @ 3, PIC Bus Number @ 4096, PIC Address Number @ 4097, PIC Baud Rate @ 4098, Hour @ 8192, Minutes @ 8193, Point Value Registers starting at 16384, 16640, 16896, 17152) — confirmed by Carrier Translator Manual 808-356 01/05

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.

If your device isn't here, upload its register map. Generation is free, and the connector keeps the rung it earns under testing.

To prove a connector against your own device, order hardware verification. If it doesn't verify, you don't pay.

Platform builders can license the verified library: machine-readable maps, the firmware matrix, API access.