Soil NPK 3 in 1 Sensor Agricultural with MAX485 ModBus Module Kit

Key Features

• 3-in-1 measurement of soil Nitrogen, Phosphorus, and Potassium.
• RS485 digital communication suitable for embedded and automation systems.
• MAX485 Modbus interface module included for convenient RS485 connectivity.
• Stainless-steel probe designed for soil insertion.
• Sealed sensor construction for agricultural environments.
• Designed to resist electrolysis, salt, and alkaline corrosion.
• Stated measurement range of 0–199 mg/kg.
• 1 mg/kg stated resolution.
• Fast response time of less than 10 seconds (T90).
• Wide 5–24V DC operating supply range.
• Suitable for Arduino, ESP32, PLC, and other RS485-capable systems.

Applications

• Smart agriculture and precision farming.
• Soil fertility monitoring.
• Greenhouse and agricultural automation.
• Automated fertilizer monitoring systems.
• Plant cultivation and soil research.
• IoT-based agricultural monitoring.
• Arduino and ESP32 soil-monitoring projects.
• PLC and industrial automation systems.

Modbus / RS485 Integration

The sensor communicates digitally through an RS485/Modbus interface. The included MAX485 module can be used as the electrical interface between the RS485 sensor bus and a compatible TTL-based microcontroller.

When connecting the kit to an Arduino, ESP32, or similar controller, the appropriate RS485 wiring and communication settings must be used. Software should be configured according to the sensor's Modbus register map and communication protocol.

Calibration

The NPK sensor should be calibrated before its readings are treated as accurate soil nutrient measurements. Soil composition, moisture, temperature, density, and other environmental factors can affect the measured values.

For applications requiring dependable nutrient analysis, use appropriate reference soil measurements to establish calibration values and verify the sensor after calibration.

Important Notes

• This sensor is intended for monitoring and development applications and should not automatically be considered a laboratory-grade soil analyzer.
• Calibration is required for meaningful NPK measurements.
• The MAX485 module provides the RS485 electrical interface; it does not replace the sensor's Modbus communication protocol.
• Confirm the sensor's Modbus address, baud rate, register map, and other communication parameters before programming.
• Do not force the probe into extremely hard or rocky soil.
• Keep connectors, exposed electrical connections, and cable joints protected from unnecessary moisture.
• Actual measurement performance may vary according to soil conditions and installation.
• Product dimensions and physical measurements may have minor manufacturing or measurement variations.

Package Includes

• 1 × Soil NPK 3-in-1 Agricultural Sensor
• 1 × MAX485 RS485 Modbus Interface Module

Warranty & Product Information

This is a sensor kit intended for agricultural monitoring, prototyping, research, and automation projects. No warranty or guarantee should be assumed unless specifically stated by KathalTech for the particular product listing.