A cutting unit (1) that has a cutter bar (6) that is operated rigidly or flexibly, depending on the harvest conditions, which can be operated in at least two different operating modes, wherein the cutting unit (1) includes a first sensor assembly (1) disposed on the cutting unit (1) that can be deactivated, which is for operating the cutting unit (1) in a first operating mode, and a second sensor assembly (17) for operating the cutting unit (1) in a second operating mode, wherein, when switching between the at least two operating states, the first sensor assembly (13) or the second sensor assembly (17) is activated without interruption in operation, to execute a distance determination, depending on the selected operating mode.