Capteur de salinité

When measuring a sample, the salinity sensor first obtains an accurate conductivity value, which is then converted into salinity through an internal algorithm.
Conductance or resistance is determined by measuring the current and voltage across the electrodes of the conductivity cell. Conductance (G) is defined as the reciprocal of resistance:

G = 1 / R = I / V

The conductance value depends on the geometry of the electrode plates and is represented by the constante cellulaire (K), which is the ratio of the distance between the electrodes (L) to the electrode surface area (A):

K = L / A

Où ?

• K - Constante cellulaire de l'électrode de conductivité
• A - Surface effective des plaques d'électrodes
• L - Distance entre les plaques d'électrodes

This value is known as the constante cellulaire and can be calculated based on the electrode’s physical dimensions. For example, if two square electrode plates each have an area of 1 cm² and are spaced 1 cm apart, the cell constant is K = 1 cm⁻¹.
Si la conductance mesurée (G) à l'aide de cette électrode est de 1000 μS, alors la conductivité de la solution est :

κ = 1000 μS/cm

Conductance can be converted into standardized conductivity (κ), which is independent of the electrode configuration. This is done by multiplying the conductance by the cell constant:

κ = G × L / A = G × K

This conductivity value is then used to calculate salinity through predefined conversion formulas within the sensor.