Method and control system for recognizing a fault when processing data in a processing system

A processing system for recognizing a fault when processing input data to form a data packet which contains output data and a test data item for confirming the validity of the output data, the system comprising:

• a processing unit for the purpose of executing processing steps serially and in so doing ascertaining the output data on the basis of the input data in line with a first processing method and determining the test data item on the basis of the input data in line with a second processing method, wherein determining the test data item involves intermediate output data being ascertained on the basis of the input data in line with a third processing method and determining the test data item from the ascertained intermediate output data in line with a fourth processing method, the first processing method and the third processing method implementing the same function by different routes;
• and
• a memory which stores the method steps from the first and second processing methods;
• wherein a receiver of the data packet formed from the output data and the test data item recognizes a fault in the processing system if the validity of the output data cannot be confirmed by the test data item;
• and
• wherein the processing unit discards the intermediate output data following the determination of the test data item in line with the fourth processing method.