A method for operating an electromagnetic flowmeter and a flowmeter are provided. The method can include providing the stream rich in an aromatic C9 from a first fractionation zone that receives an effluent from a second fractionation zone. The wireless network receiving module is disposed on the heat-dissipating unit, and the wireless network receiving module includes a first substrate unit and a second substrate unit electrically connected to the first substrate unit. The medical instrument is released for the operation by the certain user only in case of agreement between the detected individual biometric features of the certain user and biometric features of at least one user, which were entered in the memory in advance. A plurality of first upper repair lines is formed at the upper peripheral region of the substrate, crossing one or more blocks of the signal lines.