Access-level control apparatus

An access-level control apparatus comprising:

• an NC machine tool;
• an RFID held by an operator, the RFID storing an ID given to the operator;
• a reader unit that reads out the ID in the RFID;
• an authenticating unit that determines operator processing limitation information including an operable range by the operator associated with the ID or display information provided to the operator;
• an operation/display limiting unit that limits processing by the operator for the NC machine tool on the basis of the operator processing limitation information;
• and
• a separation detecting unit that periodically reads out, after the authentication, the ID in the RFID via the reader unit, performs re-authentication, and detects presence or absence of separation of the operator, wherein
• the reader unit includes a transmission antenna that radiates a calling signal with a near magnetic field as a signal for calling the RFID,
• as a result of the re-authentication, the separation detecting unit detects separation of the operator based on a distance of the operator from the transmission antenna, the distance being estimated from a change in reception intensity during the re-authentication acquired by the RFID,
• the authenticating unit releases the limitation of the processing by the operator, and
• if the signal received form the reader unit is a normal call signal, then the RFID responses to the reader unit and if the signal received form the reader unit is not the normal call signal, then the RFID does not response to the reader unit.