Digital Soil pH Probe RS485 pH Sensor
>>Technical Parameter
Power Supply: 9~36VDC
Output: RS485 MODBUS RTU
Measuring Material: Glass/Silver + Silver Chloride
Housing Material: PP
Waterproof Rating: IP68
Measuring Range: 0-14pH
Accuracy: ±0.05pH
Pressure Range: ≤0.3MPa
Temperature Compensation: NTC10K
Temperature Range: 0-80℃
Calibration: Sample Calibration, Standard Solution Calibration
Connection: 4-core Cable
Cable Length: Standard 10m cable, extendable up to 100m
Installation Thread: PG13.5
Application: Soil Online Monitoring
>>Overview
The core theory of pH electrode measurement is the Nernst equation.
The sensor used in potentiometric analysis is called a galvanic
cell. A galvanic cell is a system that converts chemical reaction
energy into electrical energy. The voltage of this cell is referred
to as the electromotive force (EMF). This EMF consists of two
half-cells. One half-cell is the measuring sensor, whose potential
is related to the activity of specific ions; the other is the
reference half-cell, often called the reference sensor, which is
typically connected to the measurement solution and the instrument.
>>Electrode Maintenance and Care
○ Before use, unscrew the protective cap and immerse the electrode
bulb and liquid junction in the sample.
○ If salt crystals form near the electrode tip or inside the cap
due to electrolyte evaporation, rinse with water. This indicates
normal dialysis membrane function.
○ Check for air bubbles in the glass bulb by shaking the electrode
vertically.
○ Keep the glass membrane hydrated for fast response. After
measurement or calibration: Rinse the electrode thoroughly. Add
storage solution (3 mol/L KCl) to the protective cap.
○ Ensure terminal connections remain dry. Clean with anhydrous
alcohol if contaminated.
○ Avoid prolonged immersion in distilled water, protein solutions,
or contact with silicone grease.
○ For aged electrodes with cloudy membranes or deposits, soak in
10% HCl, then rinse.
○ Regularly clean and calibrate the electrode. If calibration fails
after maintenance, replace the electrode.
>>Lifespan
Under normal conditions with proper maintenance, electrodes last
over 12 months. Even unused electrodes have a shelf life of 12–24
months (if stored correctly). Exposure to strong acids, bases, high
temperatures, or corrosive liquids shortens lifespan. Electrodes
are consumables and generally not covered by warranty.
>>Electrode Calibration
○ Use fresh pH/ORP standard buffer solutions of appropriate
concentrations.
○ Remove the protective cap and rinse the electrode with distilled
water.
○ Set the instrument to calibration mode (refer to the instrument
manual for details).
○ After calibration, measure actual samples.
