1. On-line diagnosis On-line diagnosis refers to the control program of the numerical control system, under the normal operation of the system, the input/output of the numerical control device, PLC controller, servo system, PLC and other external devices connected with the numerical control device are automatically tested and inspected, and the relevant status information and fault information are displayed. The system not only displays the alarm number and alarm content on the screen, but also displays the status of NC internal flag register and PLC operation unit in real time, which provides great convenience for fault diagnosis.

2. Off-line diagnosis When the numerical control system of the numerical control machine tool fails or it is judged that there is a fault in ancient times, it is often necessary to stop the processing and stop the machine for inspection. This is the off-line diagnosis.