Control device for indexing a stepping rotatable member

Claim 1

A control device for indexing stepping rotatable member comprising: a stepping rotatable member which can stop at a plurality of angular positions; an indexable rotative drive apparatus which rotates said stepping rotatable member; means for generating different positional code signals at every stop position of said stepping rotatable member; means for generating incremental strobe signals at every stop position of said stepping rotatable member; a control circuit which controls the operation of said indexable rotative drive apparatus; a numeric means for supplying indexing command values; a first comparator circuit which detects a coincidence between an indexing command value and said code signal; a counter, which can be preset by said control circuit and which counts said strobe signals; and a second comparator circuit which detects a coincidence between a count signal of said counter and said code signal value, such that said control circuit supplies a rotation command to said indexable rotative drive apparatus when said indexing command is supplied thereto from said numeric means, supplies a stop command to said rotative drive apparatus when said first comparator circuit detects a coincidence, and outputs an "end of indexing signal" to said numeric means when both said first and second comparator circuits detect coincidences.