What baud rate does the JXBS-3001-NPK-RS use by default?

9600 bps, 8N1. It is a Modbus-RTU slave; default address 1.

What supply voltage does the JXBS-3001-NPK-RS need?

DC 12–24 V (≤ 0.15 W (12 V DC)).

How do I change the JXBS-3001-NPK-RS Modbus address?

Write the device-address register with function code 0x06, one device on the bus at a time, then power-cycle. See the Configuration section above.

Is the JXBS-3001-NPK-RS compatible with the Sankhya platform?

Yes — it is in the Sankhya RS-485 sensor library and the firmware-generation pipeline can produce node firmware for it.

What does the JXBS-3001-NPK-RS not measure?

The JXBS-3001-NPK-RS reports N-P-K only — it does not report moisture, temperature, EC, pH, salinity and TDS. On the same RS-485 bus, add moisture: JXBS-3001-TR (4-in-1); temperature: JXBS-3001-TR (4-in-1); EC: JXBS-3001-TR (4-in-1).

How many Modbus registers does the JXBS-3001-NPK-RS expose?

This guide documents 5 registers, read with function code 0x03 and written with 0x06 where the register is RW. Documented entries include Nitrogen, Phosphorus, Potassium, Device address and Baud rate.

Does this N-P-K sensor also report pH?

No. It is the N-P-K-only JXCT variant. A pH probe or multi-parameter model must be added when pH is needed.

Can I use it for home gardening?

Yes, provided the installation and calibration effort make sense for the garden. The industrial interface is the same; a small deployment simply uses fewer devices.

Home / Sensors / JXBS-3001-NPK-RS

JXCT · RS-485 sensor

Weihai JXCT Electronics

JXBS-3001-NPK-RS

JXCT standalone N-P-K probe (3 registers from 0x001E).

✓ Verified for SankhyaN-P-KVerification 0.95 · datasheet-confirmed

At a glance

The JXBS-3001-NPK-RS is a single-parameter RS-485 soil probe reporting N-P-K over Modbus-RTU on RS-485 at 9600 bps, 8N1, on DC 12–24 V. This guide documents 5 registers, default Modbus address 1. It does not report moisture, temperature, EC and others. For those on the same bus: moisture → JXBS-3001-TR (4-in-1); temperature → JXBS-3001-TR (4-in-1). Sankhya firmware profile: JXCT_NPK_only.

Sankhya Farms integration

A focused N-P-K sensor does not need a generic IoT stack

The JXBS-3001-NPK-RS is supported through Sankhya's JXCT_NPK_only profile. The node reads the three live nutrient words at 9600 baud and sends labelled nitrogen, phosphorus and potassium values to the free cloud dashboard. That provides a practical route from a 12–24 V RS-485 probe to history and comparison without writing a custom poller or deciding later which anonymous database column was N, P or K.

A single-purpose probe can be useful in field comparisons, pot trials, greenhouse beds, home-garden experiments and bench validation against known samples. It can also share a bus with separate moisture, temperature, EC or pH sensors, allowing the nutrient series to be viewed in context. The dashboard can remain a read-only observation record. This is a soil or compatible substrate probe, not a nutrient-reservoir analyser; liquid hydroponics calls for instruments designed and calibrated for the solution. As with any in-situ N-P-K instrument, the dashboard should not lend false certainty: compare readings with reference methods, note moisture and soil type, and treat unexpected shifts as a reason to investigate rather than an automatic fertiliser instruction.

Collected fields: N, P and K in mg/kg. Moisture and temperature are not hidden extra channels on this model; add another supported probe if those measurements are required. Browse sensors by parameter.

Value lookup

Where are the JXBS-3001-NPK-RS nutrient values?

Poll three holding registers beginning at 001EH. Nitrogen is 001EH (PLC 40031), phosphorus is 001FH and potassium is 0020H. Each word is an unsigned 16-bit integer with a scale of 1 mg/kg. Address and baud configuration are at 0100H and 0101H. Sankhya converts the returned sequence into named nutrient fields before upload.

Does this N-P-K sensor also report pH?: No. It is the N-P-K-only JXCT variant. A pH probe or multi-parameter model must be added when pH is needed.
Can I use it for home gardening?: Yes, provided the installation and calibration effort make sense for the garden. The industrial interface is the same; a small deployment simply uses fewer devices.

Quick reference

Bus & electrical specs

Protocol

Modbus-RTU over RS-485

Default baud

9600 bps

Serial format

8N1

Function codes

0x03

Supply voltage

DC 12–24 V

Power

≤ 0.15 W (12 V DC)

Default address

Ingress / housing

IP68

Probe / element

316L stainless steel

Operating temp.

−40 to +80 °C (probe)

Firmware profile

JXCT_NPK_only

Specs sourced from: Official JXBS-3001-TR datasheet (R208894) and JXCT manuals.

Modbus-RTU register map

Function codes 0x03 at 9600 bps, 8N1. Data registers are read with 0x03; configuration registers are written with 0x06. PLC column shows the 4xxxx Modbus holding-register convention.

Register	PLC	Parameter	Type	Scale	Unit	R/W	Notes
001EH	40031	Nitrogen	uint16	1	mg/kg	RO
001FH	40032	Phosphorus	uint16	1	mg/kg	RO
0020H	40033	Potassium	uint16	1	mg/kg	RO
0100H	40257	Device address	uint16	1	—	RW
0101H	40258	Baud rate	uint16	1	—	RW	2400=2400; 4800=4800; 9600=9600

Example poll

Worked query

Configuration

Changing address & baud rate

This probe is configured over the same RS-485 bus using Modbus write commands (function code 0x06). Configure one device at a time on the bus.

Set the Modbus slave address by writing register 0100H (PLC 40257) with function code 0x06.
Set the baud rate by writing register 0101H (PLC 40258). Values: 2400=2400, 4800=4800, 9600=9600.
Power-cycle the probe after a configuration write for the change to take effect.

Field notes

Notes & caveats

NPK-only variant. Live probe readings confirmed from uploaded manual. Default baud 9600.

FAQ

Common questions

What baud rate does the JXBS-3001-NPK-RS use by default?: 9600 bps, 8N1. It is a Modbus-RTU slave; default address 1.
What supply voltage does the JXBS-3001-NPK-RS need?: DC 12–24 V (≤ 0.15 W (12 V DC)).
How do I change the JXBS-3001-NPK-RS Modbus address?: Write the device-address register with function code 0x06, one device on the bus at a time, then power-cycle. See the Configuration section above.
Is the JXBS-3001-NPK-RS compatible with the Sankhya platform?: Yes — it is in the Sankhya RS-485 sensor library and the firmware-generation pipeline can produce node firmware for it.
What does the JXBS-3001-NPK-RS not measure?: The JXBS-3001-NPK-RS reports N-P-K only — it does not report moisture, temperature, EC, pH, salinity and TDS. On the same RS-485 bus, add moisture: JXBS-3001-TR (4-in-1); temperature: JXBS-3001-TR (4-in-1); EC: JXBS-3001-TR (4-in-1).
How many Modbus registers does the JXBS-3001-NPK-RS expose?: This guide documents 5 registers, read with function code 0x03 and written with 0x06 where the register is RW. Documented entries include Nitrogen, Phosphorus, Potassium, Device address and Baud rate.

Alternatives

How this differs from similar models

How the JXBS-3001-NPK-RS compares with the other RS-485 models in the Sankhya library. "Drop-in" means the same parameter set and the same register map, read by the same firmware profile.

Model	Relationship	Measures	Baud	Difference
JXBS-3001-TR (7-in-1)	Sibling	Moisture, Temperature, EC, pH, N-P-K	9600	Adds moisture, temperature, EC and pH.
JXBS-3001-PH-RS	Sibling	pH	9600	Adds pH, drops N-P-K.
JXBS-3001-TR (4-in-1)	Sibling	Moisture, Temperature, EC, pH	9600	Adds moisture, temperature, EC and pH, drops N-P-K.

Same family

Related JXCT sensors

Run this sensor on a Sankhya node

Every sensor on this page is in our RS-485 library. Pick your model, and the firmware-generation pipeline builds the Modbus (or ASCII) polling code for an ESP32-S3 node — no hand-coding the register math.