During operation of machines and installations, it is highly important to select the optimum time for carrying out servicing operations. If intervention is made too early, unnecessary costs arise due to the premature replacement of components. If, in contrast, intervention is made too late, there is a risk of a component failing, and this may sometimes lead to failure of an entire installation. The bearings of a machine are primarily parts which are subject to wear and have to be regularly serviced and, respectively, replaced when wear occurs. Defective bearings often result in severe consequential damage. Different sensor systems are known for determining the optimum time at which a bearing, in particular a roller bearing, has to be replaced, it being possible for wear phenomena and/or damage to the bearing to be detected by said sensor systems.
In this connection, it is known to monitor a state using integrated vibration analysis in order to allow an alert to be issued at a precise time and in a robust manner and therefore to allow dangerous operating states to be identified in good time and to allow corresponding countermeasures to be initiated. In many cases, bearings are monitored for damaging frequencies in the frequency range of from 2 Hz to 10 kHz in the linear frequency range of a sensor by means of FFT analysis and input of mechanical properties, in particular taking into account the geometry of the roller bearing, and also of the rotation speed. Another technical solution makes provision for intermittent vibrations which are caused by damaging patterns, so-called shock pulses, to be analyzed using a resonant vibration pick-up in the ultrasound range. Both of the abovementioned methods are suitable for ascertaining the actual state of a bearing. In order to visualize the state of a bearing, auxiliary means which indicate whether a bearing is still intact or has already been damaged are known in this connection.