Abstract: A hydrocyclone for separating feed into overflow and underflow comprises a feed inlet, an overflow outlet, an apex for discharging underflow, an upper section connected to the feed inlet and the overflow outlet, a conical section between the upper section and the apex and a plurality of electrodes for measuring electrical conductivity inside the hydrocyclone to detect the formation of a roping state in the hydrocyclone. The plurality of electrodes are is positioned circumferentially in the conical section on an axial distance from the apex (dmeas); wherein dmeas is at least 5 percent of the axial distance be-tween the apex and the upper section, and dmeas is at most 50 percent of the axial distance between the apex and the upper section.