Electrical conductivity of the process liquid must meet a certain minimum value, but that is all.
It is surprising to some technicians that changes in liquid conductivity have little to no effect on
flow measurement accuracy. It is not as though a doubling of liquid conductivity will result in a
doubling of induced voltage! Motional EMF is strictly a function of physical dimensions, magnetic
field strength, and fluid velocity.
Liquids with poor conductivity present a greater electrical resistance in the voltage-measuring
circuit than liquids with good conductivity, but this is of little consequence because the input
impedance of the detection circuitry is phenomenally high. The effect of liquid conductivity on
flowmeter operation may be modeled by the following DC circuits