FAULT DIAGNOSTIC METHOD FOR NUMERICAL CONTROLLER

PURPOSE:To know beforehand a fault before a serious malfunction is generated by executing a retry when a malfunction of a constituting part has been generated, monitoring a history of the retry which has been executed and deriving a retry frequency. CONSTITUTION:After use of a storage device 2 or an input/output device 3 has been executed, in case a slight malfunction has been detected by a malfunction detecting part 4, and in case a retry caused by a slight malfunction has been shown by a retry control part 5, a retry frequency is calculated by a retry frequency calculating part 7. Subsequently, the retry frequency which has been obtained is inspected, whether the retry frequency shows a forerunning phenomenon of a fault or not is confirmed, and in case the retry frequency does not show the forerunning phenomenon of a fault, the operation returns to the previous step and the operation from use of the device 2 or the device 3 is repeated. On the other hand, in a deciding step, in case the retry frequency shows the forerunning phenomenon of a fault, it is considered to have known beforehand the forerunning phenomenon of a fault, namely, the fault and a processing for coping with the forerunning phenomenon of a fault is executed, the operation returns to the previous step and the operation from use of the device 2 or the device 3 is repeated.