METHOD FOR CAPTURING DIAGNOSTIC DATA IN A MOTOR VEHICLE BY MEANS OF A VOLATILE RING BUFFER AND SUBSEQUENT DATA REDUCTION IN A NON-VOLATILE MEMORY

摘要

The invention relates to a data capture, wherein a specific observer is activated for every operating state of a vehicle. Said operating state specific observer monitors the prescribed events corresponding to the associated task thereof for occurrence within the monitoring range thereof. The prescribed events can hereby be defined by bus messages or by specific measuring and control parameters of the sensors or actuators to be monitored. If a monitored event occurs, the observer determines which information is to be logged for evaluating said event. The event-specific relevant information is hereby associated with the events to be monitored, for example in a look-up table. In a further step, the data content of cyclically rewritable volatile ring buffer is then searched for the determined information, preferably by the observer itself. When searching the ring buffer for the determined information, the information logged chronologically in the ring buffer is reduced with regard to the number and quantity, before it is stored in a non-volatile second memory medium. A first data reduction during the search of the ring buffer takes place by means of a time window associated with the event that occurred, said window extending over a prescribed time interval about the event. Only information from said determined time window is selected for storage in the non-volatile memory. In addition to selecting by means of a time window, a further reduction of the information to be selected takes place during the search, in that the chronologically logged information within the time window is further reduced in number or quantity by means of a discretizing selection.