Adaptive alarm controller changes multiple inputs to industrial controller in order for state word to conform with stored state word

Claim 1

A heuristic error correction system for an industrial controller with multiple inputs and outputs for controlling a process having at least one process state comprising: input means for receiving certain of the multiple inputs and outputs from the industrial controller as status input signals; a transition detector means coupled to the input means for collecting the status input signal into a state word and for detecting changes in the process state as indicated by changes in the state word; a content addressable memory receiving the state word from the transition detector and responsive to changes in the state word indicated by the transition detector and, in a learn mode, for storing the state word and, in an alarm mode, for identifying whether the state word has been previously stored and if not for producing a miss signal; signal means for receiving the miss signal from the content addressable memory and for signalling when the heuristic error correction system is in the alarm mode and the state word cannot be identified as previously stored; and a correcting means responsive to said signal means for changing the multiple inputs to the industrial controller so that ht estate word conforms to a stored state word.