Abstract: The invention proposes a control device having a monitored operating element (1, 10). The operating element is used for introducing and forwarding an input command (14) to control systems, particularly of machines, plant or the like. In this arrangement, an oscillating movement (13) is imparted to the operating element by a drive (3, 4), which is constructed, for example, as a magnetic system, which movement is detected by the control system, particularly by means of a sensor (5, 6) which can also be constructed as an electromagnetic system. If an input command (14) is introduced into the operating element, it experiences a restriction in mobility by coming to rest against a fixed stop (8), so that no or only a smaller signal is introduced into the sensor and thus the control system. The same effect occurs if the mobility is reduced unintentionally by internal or external influences such as corrosion in the bearing points, fracture of the operating element and so forth.