Automatic electrical control system having plural comparators and automatic disabling of coarse comparator

Claim 1

AN ELECTRICAL CONTROL ARRANGEMENT COMPRISING: A CONTROLLED ELEMENT; AN ACTUATOR COUPLED TO SAID CONTROLLED ELEMENT; A FIRST PATH FOR A FIRST INPUT SIGNAL; A SECOND PATH FOR A SECOND INPUT SIGNAL; A FIRST CIRCUIT MEANS COUPLED TO SAID CONTROLLED ELEMENT AND SAID FIRST PATH TO PRODUCE A FIRST ERROR SIGNAL HAVING AN AMPLITUDE PROPORTIONAL TO A FIRST GIVEN INDICATION OF A MISADJUSTMENT OF SAID CONTROLLED ELEMENT; A SECOND CIRCUIT MEANS COUPLED TO SAID CONTROLLED ELEMENT AND SAID SECOND PATH TO PRODUCE A SECOND ERROR SIGNAL HAVING AN AMPLITUDE PROPORTIONAL TO A SECOND GIVEN INDICATION OF A MIDADJUSTMENT OF SAID CONTROLLED ELEMENT DIFFERENT THAN SAID FIRST GIVEN INDICATION; A LEVEL DETECTOR MEANS COUPLED TO SAID FIRST PATH TO PRODUCE A BIAS VOLTAGE HAVING AN AMPLITUDE PROPORTIONAL TO THE AMPLITUDE OF SAID FIRST INPUT SIGNAL A SWITCHING MEANS COUPLED TO SAID ACTUATOR TO CONTROL THE OPERATION THEREOF IN RESPONSE TO SAID FIRST AND SECOND ERROR SIGNALS; CIRCUIT ELEMENT MEANS HAVING NON-LINEAR CURRENT-VOLTAGE CHARACTERISTICS COUPLED TO THE COUPUT OF SAID LEVEL DETECTOR AND BIASED BY SAID BIAS VOLTAGE TO ESTBLISH A GIVEN THRESHOLD LEVEL; SAID CIRCUIT ELEMENT MEANS COUPLED TO THE OUTPUT TERMINALS OF SAID FIRST CIRCUIT MEANS AND SAID SWITCHING MEANS TO COUPLE SAID FIRST ERROR SIGNAL TO SAID SWITCHING MEANS FOR CONTROL OF SAID SWITCHING MEANS BY SAID FIRST ERROR SIGNAL WHEN THE AMPLITUDE OF SAID FIRST ERROR SIGNAL IS GREATER THAN SAID THRESHOLD LEVEL AND TO BLOCK THE COUPLING OF SAID FIRST ERROR SIGNAL TO SAID SWITCHING MEANS WHEN THE AMPLITUDE OF SAID FIRST ERROR SIGNAL IS LESS THAN SAID THRESHOLD LEVEL; AND MEANS COUPLING THE OUTPUT TERMINALS OF SAID SECOND CIRCUIT MEANS TO SAID SWITCHING MEANS TO COUPLE SAID SECOND ERROR SIGNAL THERETO FOR CONTROL OF SAID SWITCHING MEANS ONLY AFTER THE AMPLITUDE OF SAID FIRST ERROR SIGNAL IS LESS THAN SAID THRESHOLD LEVEL.