Position control apparatus for circular tables

A position control apparatus for a circular table used with machine tools and the like, comprising a start position register for storing a starting position of the table, a figure zero discrimination circuit for comparing the starting position with a command position produced from a command register, said figure zero discrimination circuit discriminating whether or not said command position is such that the output of an absolute position detector for the table passes over figure zero, an angular converter for converting the output of the absolute position detector into an angular value output, an operational comparator for causing an angular value of 360.degree. to be added to or subtracted from the angular value output of said angular converter in the presence of the output of said figure zero discrimination circuit, said operational comparator producing the angular value output of said angular converter in the absence of the output from said figure zero discrimination circuit, a 360.degree. register for storing data representing the angular value of 360.degree. used for said addition to or subtraction from the angular value of the starting position of said circular table, said addition or subtraction being performed in a function generator and said operational comparator, said apparatus operating in such a manner that the sudden change in the values which occur when the output of said absolute position detector passes over the figure zero is processed as smoothly as if continuous numerical values are involved.