The Conductivity Controller is used predominantly in the water treatment industry for on/off dosing. Indication is via a bar-graph display. When the probe is immersed & the desired conductivity is present, the set point is adjusted for mid-scale of the bar-graph at which point the unit relay energises, the Red LED illuminates & the state of the contacts changes. Should the conductivity drop below the set-point (pre-set hysteresis), the unit relay will de-energise, the Red LED will go out the state of the contacts changes. Only the probe as supplied separately by SRE may be used.