What does cell constant mean?
A conductivity sensor cell constant describes the precise geometry of the two electrodes of the sensor. It is the ratio of the length between electrodes divided by the cross-sectional area of sample between them. It directly affects the sensitivity and accuracy of measurement. Lower cell constants are needed to provide good signals to the measuring instrument for low conductivity (high resistivity) samples. Higher cell constants are needed to measure high conductivity samples. The measuring instrument must “know” the precise cell constant of the sensor connected and normalize the readout accordingly. With Thornton Smart Sensors for 770-Series instruments, this is communicated automatically when the sensor is connected. For 200-Series instruments and sensors, the value is provided on the sensor label and certificate of calibration and should be entered into the instrument manually at startup.
