# 7 in 1 Soil Sensor (N, P, K, pH, EC, Moisture, Temperature), RS485, 5–30V

- Page: https://sigmanortec.ro/en/7-in-1-soil-sensor-n-p-k-ph-ec-moisture-temperature-rs485-530v
- Price: 447.54 RON
- Availability: In stock; 1-2 zile
- Reference: 88159 · EAN: 5947374297290
- Category: Mechatronics and IoT > Sensors and Modules > Temperature and Environmental Sensors
- Specifications: Supply Voltage: 5; Input Voltage Type: “DC” in Romanian can mean **“de ce”**, which translates to **“why”** in English.; Communication interface: RS485; Measured parameters: N, P, K, pH, EC, Umiditate, Temperatura
- Updated: 2026-09-23
- Shop: [Sigmanortec.ro](https://sigmanortec.ro/en/llms.txt)
- Prices: RON, VAT included; prices and stock as of 2026-10-22 01:37 (Europe/Bucharest)

## Description

Quickly monitor essential soil parameters for precise fertilization and irrigation, measuring N, P, K, pH, EC, moisture, and temperature in a single device, RS485 Modbus RTU communication for easy integration into SCADA or IoT projects, 316 stainless steel probes and IP68 sealed housing for long-term use, wide 5–30V power supply with low consumption.
The NPKPHCTH-S sensor is a complete soil monitoring solution, integrating the simultaneous measurement of nine parameters in a single device: humidity, temperature, electrical conductivity (EC), pH, nitrogen (N), phosphorus (P), potassium (K), salinity, and TDS (total dissolved solids).
The five probes made of 316 stainless steel ensure resistance to rust, corrosion, and prolonged electrolysis, while the sensor body is fully sealed with black flame-retardant epoxy resin, providing an IP68 protection rating suitable for continuous use in harsh agricultural environments or wet soil.
Data transmission is carried out via an RS485 interface using the industrial Modbus RTU protocol, allowing easy integration into SCADA systems, automatic weather stations, or IoT projects based on microcontrollers such as ESP32, Arduino, or Raspberry Pi.
In addition to the RS485 digital output, the sensor is also available in versions with analog outputs of 4-20 mA, 0-5 V, or 0-10 V, for compatibility with a wide range of acquisition systems. The wide power supply voltage (4.5 – 30 VDC) and low consumption (under 0.5 W at 24 VDC) make it compatible with battery-powered or solar panel installations. The connection cable has a standard length of 2 m, with customization options.
Specifications:
Operating voltage: 4.5 - 30 VDC
Maximum consumption: 0.5 W (at 24 VDC)
Interface: RS485 / 4-20 mA / 0-5 V / 0-10 V
Protocol: Modbus RTU
Humidity measurement range: 0 - 100% RH
Humidity accuracy: ±2% (0 - 50% RH), ±3% (50 - 100% RH)
Long-term humidity stability: ≤1% RH/year
Humidity response time: ≤4 s
Temperature measurement range: -40 - 80°C
Temperature accuracy: ±0.5°C
Long-term temperature stability: ≤0.1°C/year
Temperature response time: ≤15 s
Conductivity (EC) measurement range: 0 - 20000 uS/cm
Conductivity accuracy: ±3% (0 - 10000 uS/cm), ±5% (10000 - 20000 uS/cm)
Long-term conductivity stability: ≤1 uS/cm/year
Conductivity response time: ≤1 s
pH measurement range: 3 - 9 pH
pH accuracy: ±0.3 pH
Long-term pH stability: ≤5%/year
pH response time: ≤10 s
NPK measurement range: 1 - 1999 mg/kg
NPK resolution: 1 mg/kg
NPK response time: ≤1 s
Cable length: 2 m (customizable)
Probe material: 316 stainless steel
Housing material: Black flame-retardant epoxy resin
Protection rating: IP68
Operating temperature: -40 - 80°C
Dimensions: 45 x 15 x 123 mm
Probe Pinout:
Pin
Color
Function
1
Brown
VCC (4.5 - 30 VDC)
2
Black
GND
3
Yellow
RS485 A+ (Data+)
4
Blue
RS485 B- (Data-)
Registers:
Register
Parameter
Unit
Factor
0x0000
Humidity
%RH
/10
0x0001
Temperature
°C
/10
0x0002
Conductivity
uS/cm
x1
0x0003
pH
/10
0x0004
Nitrogen (N)
mg/kg
x1
0x0005
Phosphorus (P)
mg/kg
x1
0x0006
Potassium (K)
mg/kg
x1
0x0007
Salinity
g/L
x1
0x0008
TDS
mg/L
x1
Usage:
Insert the probes fully into the soil up to the mark on the sensor body, avoiding contact with stones or roots.
Connect the wires according to the pinout table to the RS485 module (MAX485 or similar) or directly to the RS485-USB converter.
Power the sensor with a voltage between 4.5 and 30 VDC on the brown wire (+) and black wire (GND).
Connect the yellow wire to terminal A+ and the blue wire to terminal B- of the RS485 module.
Configure the serial port with the following parameters: baud rate 4800, 8 data bits, no parity, 1 stop bit (4800 8N1).
Send individual Modbus RTU commands to the default address 0x01 for each desired register, according to the register table above.
Interpret the received values by applying the corresponding scale factor for each parameter.
After use, clean the probes with clean water and store the sensor protected from freezing.
Test code with ESP32 and RS485 Module: