Controller for machine tool including automatic tool changer

A controller for a machine tool including an automatic tool changer, the automatic tool changer including

• a tool post that can house a plurality of tools and position a desired tool to a specific position,
• a tool post driving motor that drives the tool post, and
• a tool change mechanism that changes a tool indexed to a specific position in the tool post and a tool attached to a spindle,
• the controller comprising:
• a movement amount estimation section that estimates an amount of movement of the tool post driving motor in tool indexing based on a tool pot number at a tool change position in the tool post before tool changing and a tool change instruction code;
• a motor movement amount acquisition section that acquires an amount of movement of the tool post driving motor in tool indexing;
• and
• an abnormality notification section that provides notification of an abnormality if a difference between the amount of movement of the tool post driving motor acquired by the motor movement amount acquisition section and the amount of movement of the tool post driving motor estimated by the movement amount estimation section has exceeded a permissible range.