What baud rate does the DFRobot SEN0604 use by default?

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

What supply voltage does the DFRobot SEN0604 need?

DC 5–30 V (Low (RS-485 bus-powered class)).

How do I change the DFRobot SEN0604 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 DFRobot SEN0604 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.

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DFRobot · RS-485 sensor

DFRobot

DFRobot SEN0604

Name: DFRobot SEN0604
Brand: DFRobot

DFRobot 4-in-1 — moisture, temp, EC, pH (with salinity/TDS).

✓ Verified for SankhyaMoistureTemperatureECpHSalinityTDSVerification 0.95 · datasheet-confirmed

Quick reference

Bus & electrical specs

Protocol

Modbus-RTU over RS-485

Default baud

9600 bps

Serial format

8N1

Function codes

0x03, 0x06

Supply voltage

DC 5–30 V

Power

Low (RS-485 bus-powered class)

Default address

Ingress / housing

IP68

Probe / element

316 stainless steel

Operating temp.

−40 to +80 °C (probe)

Firmware profile

DFROBOT_4in1

Specs sourced from: Official DFRobot wiki (SEN0600–SEN0605 product pages).

Modbus-RTU register map

Function codes 0x03, 0x06 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
0000H	40001	Soil moisture	uint16	0.1	%	RO
0001H	40002	Soil temperature	int16	0.1	°C	RO
0002H	40003	Electrical conductivity	uint16	1	uS/cm	RO
0003H	40004	pH	uint16	0.1	pH	RO
0007H	40008	Salinity	uint16	1	mg/L	RO	Reference only.
0008H	40009	TDS	uint16	1	mg/L	RO	Reference only.
0022H	40035	Conductivity temperature coefficient	uint16	0.1	%	RW
0023H	40036	Salinity conversion coefficient	uint16	0.01	—	RW
0024H	40037	TDS conversion coefficient	uint16	0.01	—	RW
0050H	40081	Temperature calibration	int16	0.1	°C	RW
0051H	40082	Moisture calibration	int16	0.1	%	RW
0052H	40083	Conductivity calibration	int16	1	uS/cm	RW
0053H	40084	pH calibration	int16	0.1	pH	RW
07D0H	42001	Device address	uint16	1	—	RW
07D1H	42002	Baud rate	uint16	1	—	RW

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 07D0H (PLC 42001) with function code 0x06.
Set the baud rate by writing register 07D1H (PLC 42002).
Power-cycle the probe after a configuration write for the change to take effect.

Field notes

Notes & caveats

Official map. 4-in-1: moisture+temp+EC+pH.

FAQ

Common questions

What baud rate does the DFRobot SEN0604 use by default?: 9600 bps, 8N1. It is a Modbus-RTU slave; default address 1.
What supply voltage does the DFRobot SEN0604 need?: DC 5–30 V (Low (RS-485 bus-powered class)).
How do I change the DFRobot SEN0604 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 DFRobot SEN0604 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.

Same family

Related DFRobot 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.

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