US Patent 7580770 Numerical controller

A path table operation is performed while updating the reference positions. When a read-out command in the path cycle table is read out, the reference positions are withdrawn and reset, and the respective axial positions at the time of the initiation of the path cycle command are stored. From the next period, the target positions are determined by adding the positions at the time of initiation to the respective axial positions corresponding to the reference positions stored in the path cycle table, and a path table operation is performed. A single path cycle table is sufficient for storing commands for portions to be repeatedly worked.