Ultrasonic sensor systems are perfectly suited for near-field monitoring of the working area of mobile machines. The sensor systems allow the greatest possible flexibility in installation and application. The scalable system with h 4, 6, 8, or 12 ultra sonic sensors controlled by one single system control unit, can be configured with several parameters. Thanks to sophisticated filter technology, the sensor system provides reliable distance or position information even under the most difficult environmental conditions and warns of objects within the sensors' field of view. The ultrasonic sensor systems are ideal for use as an assistance system to increase safety on mobile machines. For safety applications, the system provides PL d safety function comprises the distances detected by the sensors - direct echoes.