- Simple clipping of the symbol disc in the touch sensor - Reliable identification of different functions Capacitive touch sensors can be used, for example, as a start and stop button on machines, as enable switches and for opening and closing gates. Compared to mechanical switches the sensors operate without wear. The symbol disc for the sensing face is snapped on after installation of the sensor. No sensor alignment is required during installation. For 100 mm diameter touch sensors, coloured cover rings can be used to mark different functions.