Numerical control system

A numerical control system, comprising:

• an NC unit;
• a programmable machine controller for executing at least sequence control based on signals from the NC unit and a machine tool;
• a computerized man-machine interface controller having at least a computer, a CRT connected to the computer and a keyboard connected to the computer;
• and
• a data exchange controller connected to said NC unit, said machine controller and the computer of said interface controller, and data being exchanged among the NC unit, programmable machine contoller and man-machine interface controller under the control of said data exchange controller;
• wherein both said NC unit and said programmable machine controller include computers;
• and
• wherein said machine controller includes a bus, said NC unit includes a bus, and said data exchange controller has a common RAM, a high-speed interface controller, and a bus controller connected, for bidirectional data exchange with said common RA, said high-speed interface controller, the bus of said programmable machine controller, and the bus of said NC unit;
• and said man-machine interface controller having a high-speed interface controller connected to the high-speed interface controller of the data exchange controller and connected to the computer of said interface controller.