Method for controlling a machine tool

A method for controlling a numerical control machine tool by means of a system with a sensor device, a control unit, an interface unit electrically connected to the sensor device and to the control unit, and a connection cable implementing a digital channel for electrical connection between the interface unit and the control unit, the control unit being adapted to control the performance of a measuring instruction and to detect a digital measuring signal consequently received within a determined time interval through said digital channel implemented by said connection cable, the performance of the measuring instruction including mutual displacements between the sensor device and at least one component part of the machine tool,

• wherein the control unit:
• transmits a message to the interface unit through a communication channel different from said digital channel, and
• controls the performance of a measuring instruction, including mutual displacements between the sensor device and said at least one component part of the machine tool;
• wherein the interface unit:
• receives said message,
• performs operations consequent to the contents of the message, and
• generates and transmits a digital confirmation signal through said digital channel implemented by said connection cable;
• and
• wherein the control unit:
• detects that the digital confirmation signal is received within said determined time interval through said digital channel implemented by said connection cable, and
• wherein the sensor device is an optoelectronic apparatus which detects the interruption of a light beam and includes an emitter and a receiver of said light beam,
• wherein said message is a request for checking the efficiency of a measuring chain including the optoelectronic apparatus, the interface unit and the connection cable, and
• wherein said digital confirmation signal is indicative of the positive conclusion of said checking the efficiency of the measuring chain.