Method and apparatus for automatic digital process control

Claim 1

AN ELECTRICAL DIGITAL DEVICE FOR PRODUCING AN INDICATION REPRESENTATIVE OF THE DEPARTURE OF AN INPUT QUANTITY FROM A PREDETERMINED REFERENCE VALUE BEYOND A PRESELECTED PERCENTAGE OF SAID REFERENCE VALUE COMPRISING A UNIDIRECTIONAL BINARY COUNTER HAVING A PLURALITY OF COUNTING STAGES CONNECTED IN ASCENDING BINARY ORDER, A BIDIRECTIONAL BINARY COUNTER HAVING A PLURALITY OF COUNTING STAGES CONNECTED IN ASCENDING BINARY ORDER, GATING CIRCUIT MEANS CONNECTED TO RECEIVE DIGITAL INFORMATION REPRESENTATIVE OF AN INPUT QUANTITY, SAID GATING CIRCUIT MEANS BEING CONSTRUCTED AND ARRANGED FOR PRODUCING SAID DIGITAL INFORMATION AT THE OUTPUT THEREOF DURING PRESELECTED SAMPLING PERIODS, SAID GATING CIRCUIT MEANS HAVING THE OUTPUT THEREOF COUPLED INTO BOTH SAID BINARY COUNTERS TO STORE THEREIN A FIRST BINARY COUNT OF THE NUMBER OF A FIRST SERIES OF PULSES, SAID UNIDIRECTIONAL COUNTER BEING CONSTRUCTED AND ARRANGED FOR PRODUCING AT ITS OUTPUT A FIRST SIGNAL REPRESENTATIVE OF THE ORDER OF ITS HIGHEST ORDER STAGE REGISTERING THE SAID FIRST COUNT, A FIRST ELECTRICAL SIGN CHANGE CIRCUIT COUPLED TO SAID BIDIRECTIONAL COUNTER FOR REVERSING THE COUNTING DIRECTION THEREOF AFTER THE SAID FIRST BINARY COUNT IS STORED THEREIN, BLOCKING CIRCUIT MEANS CONNECTED TO PREVENT SAID UNIDIRECTIONAL BINARY COUNTER FROM COUNTING SAID DIGITAL INFORMATION DURING THE PRODUCTION OF A SECOND SERIES OF PULSES AT THE OUTPUT OF SAID GATING CIRCUIT MEANS, SAID SECOND SERIES OF PULSES BEING INTRODUCED TO SAID BIDIRECTIONAL COUNTER SO AS TO EFFECT THEREIN A SECOND BINARY COUNT, FIRST AND SECOND NON-ADDITIVE MIXERS COUPLED TO THE OUTPUT OF SAID UNIDIRECTIONAL COUNTER AND SAID BIDIRECTIONAL COUNTER RESPECTIVELY, SENSING CIRCUIT MEANS CONNECTED TO SENSE THE OUTPUT OF SAID SECOND NON-ADDITIVE MIXER SO AS TO PRODUCE AN OUTPUT SIGNAL WHEN THE OUTPUT OF SAID SECOND MIXER REACHES A MINIMUM LEVEL, A SECOND SIGN CHANGE CIRCUIT COUPLED TO SAID BIDIRECTIONAL COUNTER AND SAID SENSING CIRCUIT MEANS TO RE-ESTABLISH THE ORIGINAL COUNTING DIRECTION THEREOF UPON RECEIVING SAID OUTPUT SIGNAL FROM SAID SENSING CIRCUIT MEANS, WHEREBY A REMANENT COUNT REPRESENTATIVE OF THE DIFFERENCE BETWEEN SAID FIRST BINARY COUNT AND SAID SECOND COUNT IS STORED IN SAID BIDIRECTIONAL COUNTER, COMPARATOR CIRCUIT MEANS CONNECTED TO BE RESPONSIVE TO THE SIGNALS CONTAINED IN SAID FIRST AND SECOND NON-ADDITIVE MIXERS TO PRODUCE A DIFFERENCE SIGNAL REPRESENTATIVE OF THE DIFFERENCE BETWEEN THE BINARY ORDERS OF SAID FIRST AND SECOND BINARY COUNTS, INDICATING MEANS COUPLED TO SAID COMPARATOR CIRCUIT MEANS TO PRODUCE AN INDICATION REPRESENTATIVE OF SAID DIFFERENCE SIGNAL, AND MEANS TO EQUALIZE THE BINARY COUNTS STORED IN SAID BINARY COUNTERS SO AS TO PREPARE SAID ELECTRICAL DIGITAL DEVICE FOR THE SUCCEEDING DIGITAL COMPARISON OPERATION.