Signal transfer system of programmable controller

A signal transfer control system for transferring I/O signals between a programmable controller and a machine tool, said system comprising:

• an I/O unit operatively connected to the machine tool and including an I/O unit memory having I/O signal regions capable of storing the I/O signals and mapping data regions corresponding to said I/O signal regions and capable of storing mapping data to identify addresses of point data to be used in transfer of I/O signals in corresponding of said I/O signal regions;
• and
• a programmable controller including
• a programmable controller memory having point data regions at point data addresses capable of storing point data to identify addresses to which the I/O signals are to be transferred and I/O data regions capable of storing the I/O signals at I/O signal addresses, and
• a central processing unit operatively connected to transfer an I/O signal from an I/O signal region of said I/O unit memory to an I/O data region of said programmable controller memory by, first, retrieving an I/O signal from an I/O signal region of said I/O unit memory and retrieving corresponding mapping data from a corresponding mapping data region of said I/O unit memory, second, retrieving point data from a point data region at a point data address identified by the mapping data retrieved from the corresponding mapping data region of said I/O unit memory, and third, storing the retrieved I/O signal in an I/O data region of said programmable controller memory having an I/O signal address identified by the point data retrieved from the point data region of said programmable controller memory.