Circuit arrangement and method for monitoring a hazardous device by evaluating the acceleration

A circuit arrangement (10, 10a, 10b, 10c) for monitoring a hazardous device comprising:

• at least two acceleration sensors (110, 210) for measuring an acceleration of at least one part of the hazardous device, wherein the at least two acceleration sensors (110, 210) are adapted to measure accelerations in three directions in space, and wherein the at least two acceleration sensors (110, 210) are arranged offset to one another by a predetermined angle to avoid common cause failures;
• at least one logic circuit (120, 220) for evaluating measured values of the at least two acceleration sensors (110, 210);
• at least one memory for storing a comparison value;
• and
• at least one safety device (130, 132;
• 230, 232;
• 134;
• 234) controlled by an output of the at least one logic circuit (120, 220), wherein the at least one safety device is adapted to bring the hazardous device into a safe state in response to a switching command received via the output of the at least one logic circuit (120, 220), and wherein the at least one logic circuit (120, 220) transmits the switching command to the at least one safety device (130, 132;
• 230, 232;
• 134;
• 234) when the measured acceleration of the at least one part of the hazardous device or a value derived from the measured acceleration has a predetermined ratio to the stored comparison value;
• wherein the circuit arrangement is adapted to test the measured values of the at least two acceleration sensors (110, 210) for plausibility, comprising a comparison of the measured values or measured variables respectively determined therefrom.