A method of supervising an E-line position in a centrifugal separator configured to separate a heavy liquid phase and a light liquid phase from a liquid feed mixture, the centrifugal separator comprising a rotor, a stack of conical separation disks arranged inside the rotor, an inlet for the liquid feed mixture into the rotor, a first outlet passage for the light liquid phase from the rotor, a second outlet passage for the heavy liquid phase from the rotor, wherein an inlet side of the first outlet passage is arranged at a first radius (R LP, R L) and an inlet side of the second outlet passage is arranged at a second radius (R HP, R G), the method comprising steps of: rotating the rotor at an angular speed (ω), feeding the liquid feed mixture into the rotor, monitoring a density (ρ LP) of the light liquid phase, monitoring a density (ρ HP) of the heavy liquid phase, monitoring a pressure (P LP, P HP) at an outlet side of the first outlet passage and/or at an outlet side of the second outlet passage, monitoring a first parameter related to a first pressure drop (ΔP LP) between the E-line position and the outlet side of the first outlet passage, monitoring a second parameter related to a second pressure drop (ΔP HP) between the E-line position and the outlet side of the second outlet passage, and continuously calculating a parameter related to the E-line position based on: the first radius (R LP, R L), the second radius (R HP, R G), the angular speed (ω), the monitored density (ρ LP) of the light liquid phase, the monitored density (ρ HP) of the heavy liquid phase, the monitored pressure (P LP, P HP) at the outlet side of the first outlet passage and/or at the outlet side of the second outlet passage, the monitored first parameter related to a first pressure drop (ΔP LP) between the E-line position and the outlet side of the first outlet passage, and the monitored second parameter related to a second pressure drop (ΔP HP) between the E-line position and the outlet side of the second outlet passage. rotating the rotor at an angular speed (ω), feeding the liquid feed mixture into the rotor, monitoring a density (ρ LP) of the light liquid phase, monitoring a density (ρ HP) of the heavy liquid phase, monitoring a pressure (P LP, P HP) at an outlet side of the first outlet passage and/or at an outlet side of the second outlet passage, monitoring a first parameter related to a first pressure drop (ΔP LP) between the E-line position and the outlet side of the first outlet passage, monitoring a second parameter related to a second pressure drop (ΔP HP) between the E-line position and the outlet side of the second outlet passage, and continuously calculating a parameter related to the E-line position based on: the first radius (R LP, R L), the second radius (R HP, R G), the angular speed (ω), the monitored density (ρ LP) of the light liquid phase, the monitored density (ρ HP) of the heavy liquid phase, the monitored pressure (P LP, P HP) at the outlet side of the first outlet passage and/or at the outlet side of the second outlet passage, the monitored first parameter related to a first pressure drop (ΔP LP) between the E-line position and the outlet side of the first outlet passage, and the monitored second parameter related to a second pressure drop (ΔP HP) between the E-line position and the outlet side of the second outlet passage. the first radius (R LP, R L), the second radius (R HP, R G), the angular speed (ω), the monitored density (ρ LP) of the light liquid phase, the monitored density (ρ HP) of the heavy liquid phase, the monitored pressure (P LP, P HP) at the outlet side of the first outlet passage and/or at the outlet side of the second outlet passage, the monitored first parameter related to a first pressure drop (ΔP LP) between the E-line position and the outlet side of the first outlet passage, and the monitored second parameter related to a second pressure drop (ΔP HP) between the E-line position and the outlet side of the second outlet passage.