Salinity Meter & Sensor

Salinity Meter is an instrument used to quickly determine the concentration or refractive index of saline solution by weight. Widely used in salt, food, beverage and other industrial sectors and agricultural production and scientific research. It usually consists of sensors, measuring circuits and data processing devices. Salinity sensor has two kinds of electrode type and induction type.

Salinity sensors are used to measure the salinity of liquids and solutions and are capable of measuring the entire range from 24 to 52,000 ppm (parts per million). Salinity is the sum of all non-carbonate salts dissolved in water and is usually expressed in parts per thousand (1 ppm = 1000 mg/L). Salinity is an important measurement in seawater. The salinity level in seawater is fairly constant at about 35 ppm (35,000 mg/L).

How does a salinity sensor work?

Apure industrial salinity sensor measures the ability of a solution to conduct a current between two electrodes. In a solution, current flows through ion transport; therefore, an increase in the concentration of ions in the solution will result in a higher conductivity value.

A salinity sensor actually measures conductance, defined as the reciprocal of resistance. Even though the salinity sensor is measuring conductivity, we are interested in finding the conductivity of the solution. A potential difference is applied to the two probe electrodes in the salinity sensor. The current generated is proportional to the conductivity of the solution. This current is converted to a voltage.

An alternating current is supplied to prevent complete migration of ions to both electrodes. With each cycle of the AC current, the polarity of the electrodes is reversed, which in turn reverses the direction of ion flow. This very important feature of the salinity sensor prevents most electrolysis and polarization from occurring at the electrodes. As a result, the solution in which the conductivity is being measured is not contaminated. It also greatly reduces the formation of redox products on the electrode.

Electrode calibration instructions

Start calibration

First step

Clean and dry the electrode, put it in the standard solution

Send command 01 02 C4 0B

After reading the measured value to be stabilized, calculate the conductivity constant, conductivity constant=standard solution value /current measured value

For example, the electrode is placed in the 1.413ms/cm standard solution and the current measured value of the electrode is 1. 450ms/cm

Then the conductivity constant=1. 413/1. 450=0.97448

To write data to the OXOA register 0.97448

Send command:01 10 00 0A 00 02 04 77 85 3F 79 A9 9F;

End of calibration

Salinity sensor installation

  1. Conductivity electrode is recommended to be instal the flow cell for more stable and accurate measurement
  2. If installing electrode in the pipe, the right angle should be 15’m165
  3. Installation method
Salinity electrode installation schematic diagram
Salinity electrode installation schematic diagram
  1. side wall installation
  2. top flange installation
  3. ipe installation
  4. top installation
  5. flow cell installation
  6. pipe Installation
  7. immersion installation
  8. anales in pipe installation

Maintenance and storage

  • The organic dirt on the electrode can be cleaned with warm water containing detergent or alcohol. After cleaning the electrode, it should be dried by soft tissue.
  • When the electrode is stored. it shall be dried and stored.
  • Cable connector must be kept clean and free from moisture or water.

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