Keller Series 30X/33X/35X pressure transmitter

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	unit
CH0 Calculated value	0	F32BE	1
P1 Pressure of sensor1	2	F32BE	1	bar
P2 Pressure of sensor2	4	F32BE	1	bar
T Temperature	6	F32BE	1	°C
TOB1 Temperature of sensor1	8	F32BE	1	°C
TOB2 Temperature of sensor2	10	F32BE	1	°C
CH0 Calculated value	16	I16	0.01
P1 Pressure of sensor1	17	I16	0.01	bar
P2 Pressure of sensor2	18	I16	0.01	bar
T Temperature	19	I16	0.01	°C
TOB1 Temperature of sensor1	20	I16	0.01	°C
TOB2 Temperature of sensor2	21	I16	0.01	°C
CH0	32	I32BE	0.00001
P1	34	I32BE	1	Pa
P2	36	I32BE	1	Pa
T	38	I32BE	0.01	°C
TOB1	40	I32BE	0.01	°C
TOB2	42	I32BE	0.01	°C
P1 Pressure of sensor1	256	F32BE	1	bar
TOB1 Temperature of sensor1	258	F32BE	1	°C
P2 Pressure of sensor2	260	F32BE	1	bar
TOB2 Temperature of sensor2	262	F32BE	1	°C
P1 Pressure of sensor1 (v5.21)	264	F32BE	1	bar
T Temperature (v5.21)	266	F32BE	1	°C
LF Conductivity Temperature Compensated	268	F32BE	1	mS/cm
UART settings	512	U16	1
FILTER_ORG	513	U16	1
S/N-H Serial Number High Bytes	514	U16	1
S/N-L Serial Number Low Bytes	515	U16	1
CFG_P Active pressure channels	516	U16	1
CFG_T Active temperature channels	517	U16	1
CFG_CH0	518	U16	1
CNT_T	519	U16	1	s
CNT_TCOMP / LP_FILT	520	U16	1
P-Mode	521	U16	1
FILT_CTRL	522	U16	1
DAC_CTRL	523	U16	1
STATUS	524	U16	1
DEV_ADDR	525	U16	1
Class:Group	526	U16	1
Year:Week	527	U16	1
ConOn	529	U16	1
STATUS (Not used)	530	U16	1
ConRange	531	U16	1
ConTempCompCoeff	532	U16	1
SPS	547	U16	1
ASCII Serial Nb	592	U16	1
Threshold value of the root function	874	F32BE	1	bar
Offset of pressure sensor P1	896	F32BE	1	bar
Gain factor of pressure sensor P1	898	F32BE	1
Offset of pressure sensor P2	900	F32BE	1	bar
Gain factor of pressure sensor P2	902	F32BE	1
Offset of analogue output	904	F32BE	1
Gain factor of analogue output	906	F32BE	1
Offset of CH0	908	F32BE	1
Gain factor of CH0	910	F32BE	1
Offset of temperature T	912	F32BE	1	°C
Offset of temperature TOB1	916	F32BE	1	°C
Offset of temperature TOB2	920	F32BE	1	°C
Minimum pressure of sensor P1	928	F32BE	1	bar
Maximum pressure of sensor P1	930	F32BE	1	bar
Minimum pressure of sensor P2	932	F32BE	1	bar
Maximum pressure of sensor P2	934	F32BE	1	bar
Minimum temperature of temperature sensor	936	F32BE	1	°C
Maximum temperature of temperature sensor	938	F32BE	1	°C
Minimum temperature of sensor P1	940	F32BE	1	°C
Maximum temperature of sensor P1	942	F32BE	1	°C
Minimum temperature of sensor P2	944	F32BE	1	°C
Maximum temperature of sensor P2	946	F32BE	1	°C
Minimum value of channel CH0	948	F32BE	1
Maximum value of channel CH0	950	F32BE	1
Pressure for minimum analogue/frequency signal	952	F32BE	1	bar
Pressure for maximum analogue/frequency signal	954	F32BE	1	bar
Minimum analogue signal	956	F32BE	1	mA, V
Maximum analogue signal	958	F32BE	1	mA, V
Gain Conductivity Range 1	992	F32BE	1
Gain Conductivity Range 2	994	F32BE	1
Gain Conductivity Range 3	996	F32BE	1
Gain Conductivity Range 4	998	F32BE	1
Conductivity Temperature Coefficient	1002	F32BE	1
Conductivity Cell Constant	1004	F32BE	1
Set Zero P1	65280	U32BE	1
Reset Zero P1	65282	U32BE	1
Set Zero P2	65284	U32BE	1
Reset Zero P2	65286	U32BE	1
Set Zero CH0	65292	U32BE	1
Reset Zero CH0	65294	U32BE	1
Set Zero T	65296	U32BE	1
Reset Zero T	65298	U32BE	1
Set Zero TOB1	65300	U32BE	1
Reset Zero TOB1	65302	U32BE	1
Set Zero TOB2	65304	U32BE	1
Reset Zero TOB2	65306	U32BE	1
Hardware Id	65488	U32BE	1

link settings as documented (unverified): RTU; default 9600 8N1; FC 03,06,08,16; Both Modbus and Keller-Protocol are active. Modbus uses L:H CRC alignment, while Keller-Protocol uses H:L.

bench facts as documented (unverified)

terminals	RS485A, RS485B, GND and +Vcc
A/B polarity	inverted (-) B / A (EIA Standard), non-inverted (+) A / B (EIA Standard)
termination	120Ohm. The transmitters will never have a terminal resistor built in internally.
shield/ground	Always connect the GND of the RS485 converter of the master with GND of the transmitter!
wiring notes	Max network length 1300m, max 128 devices. Each riser cable up to 14m.
max registers/read	80
response timeout	100 ms
inter-frame delay	2 ms
broadcast	supported
sentinel values	NaN (float) or ovl (integer) in case of an inactive channel or an error in the channel. 32767 for 16bit overflow/error, -32768 for underflow. 2147483647 for 32bit overflow/error, -2147483648 for underflow.
protocol notes	A silent interval of more than 1.5 character times between characters declares the message frame incomplete.
model register	0x020E
serial register	0x0202
firmware register	0x020E
FC 43 device ID	not supported
power	2 wires for power in feed
doc revision	Version 3.4 BV/SM 14. Oktober 2015
firmware applicability	Class.Group = 5.20, Class.Group = 5.21

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

In firmware versions prior to 10.40 (such as 5.50), the CRC of the exception code returned when using MODBUS Function 3 (F3) is incorrect. [source]
In firmware version 10.40, MODBUS Function 3 (F3) registers 0x0010 to 0x001A are not usable. [source]
confirmed: Baud rates 9600 and 115200 with default 9600 — confirmed by Communication protocol Serie30_V3.4 manual
confirmed: Both Modbus and Keller-Protocol are active with differing CRC byte alignment — confirmed by Communication protocol Serie30_V3.4 manual
confirmed: Serial register at 0x0202 and firmware/model register at 0x020E — confirmed by Communication protocol Serie30_V3.4 manual
confirmed: Silent interval of more than 1.5 character times declares frame incomplete — confirmed by Communication protocol Serie30_V3.4 manual

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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