I have a two-pole conductivity probe which operates on the principle of measuring the resistance of the liquid. Basically I use a 555 timer to generate an osillation and pass that current through the two poles of the conductivity probe. I then measure the frequency of the osillation and calculate the conductivity with a simple equation.
My problem is that the two pole probe is greatly effected by stray current and and a ground probe in the tank. Also, the conductivity probe effects the accuracy of a pH probe in the same tank.
Can anyone suggest how to isolate the conductivity probe from external effects? Shielding, etc...
My problem is that the two pole probe is greatly effected by stray current and and a ground probe in the tank. Also, the conductivity probe effects the accuracy of a pH probe in the same tank.
Can anyone suggest how to isolate the conductivity probe from external effects? Shielding, etc...