CIRCUIT DEVICE FOR SIGNAL FAULT IDENTIFICATION

PURPOSE: To easily identify the influence of a signal fault by always comparing identification data with belonging digital signals send from an A/D converter by means of a computer and triggering an error identifier when the digital signal is deviated from the identification data in an unallowable degree. CONSTITUTION: When a vehicle is started, a routine which always identifies passing faulty influences is also started and identification data KU usually filed until the influences pass are compared with a digital signal value UD. Then the value of 'X' (X=KD-UD) is obtained by forming the difference between the data KU and value UD and whether the value X is smaller than or equal to the maximum allowance XM is checked. Only when the absolute value of X is larger than that of the value of XM, a computer 2 forms an error identifier FK. The identifier FK works so that the actuation of a safety device cannot be made as far as the identifier FK exists and reset on a RESET input side only when the absolute value of X again stays within an allowable limit. Therefore, the influence of a signal fault can be identified easily.