A DSP Based Prototype for Water Conductivity Measurements

In this paper a four-electrode measurement cell is proposed for conductivity measurements. The main advantages of these cells include a wide measurement range and an intrinsic capability to minimize errors caused by fouling and polarization effects. The implemented prototype provides a flexible solution for data acquisition and signals processing and includes a capability to generate excitation signals of different frequencies and amplitudes. The proposed measurement method uses data from both, voltage and current channels to estimate the sine amplitudes, phases, DC components and common frequency, reducing the uncertainty of the estimated parameters. Conductivity temperature dependence is compensated by using a temperature sensing unit