Program control system

Claim 1

IN AN ARRANGEMENT FOR CONTROLLING THE POSITION WHICH A MOVABLE PART OCCUPIES RELATIVE TO A STATIONARY PART, THE COMBINATION WHICH COMPRISES: (A) MEANS FOR SUPPLYING DATA REPRESENTING NOMINAL POSITIONS OF SAID MOVABLE PART; (B) AN INTERPOLATER CONNECTED TO THE OUTPUT OF SAID MEANS (A) FOR CALCULATING INTERMEDIATE VALUES; (C) A CLOCK ASSOCIATED WITH SAID INTERPOLATER FOR GENERATING A TRAIN OF CLOCK PULSES THEREBY TO OPERATE SAID INTERPOLATER; (D) MEANS FOR MEASURING THE ACTUAL POSITION OF SAID MOVABLE PART; (E) COMPARISON MEANS CONNECTED TO THE OUTPUT OF SAID INTERPOLATER AND TO THE OUTPUT OF SAID MEASURING MEANS FOR PRODUCTING A VALUE REPRESENTING THE DIFFERENCE BETWEEN THE ACTUAL AND NOMINAL POSITIONS OF SAID MOVABLE PART; (F) A COUNTER CONNECTED TO SAID CLOCK AND BEING CONTROLLED BY THE TRAIN OF CLOCK PULSES PRODUCED THEREBY FOR COUNTING DOWN FROM A MAXIMUM VALUE; (G) MEANS FOR OBTAINING THE LOWEST VALUE TO WHICH SAID COUNTER COUNTS DOWN DURING THE TIME INTERVAL BETWEEN SUCCESSIVE CLOCK PULSES; (H) MEANS FOR ADDING THE OUTPUT OBTAINED FROM SAID COMPARISON MEANS AND THE OUTPUT OF SAID MEANS RECITED IN PARAGRAPH (G); AND (I) MOVING MEANS CONNECTED AND RESPONSIVE TO THE OUTPUT OF SAID ADDING MEANS FOR MOVING SAID MOVABLE PART.