ABB Liquid level relays are suitable to control the level of conductive liquids. Most water soluble and non-corrosive chemicals are acceptable. The measuring principle is based on sensing a change in resistance between the electrodes.
If the level of the liquid rises until the electrodes become wet, or if the level drops and the electrodes become dry, the output relay energizes or de-energizes, depending on the operation of the liquid level relay. An alternating measuring voltage prevents the electrolysis effect; reducing contamination deposits on the electrodes. A large selection of functions, response sensitivities and output contacts forms are available. An adjustable response sensitivity (trip point) allows setup that ignores floating foam and debris.