ABSTRACT
The structure of CNC machine tools is quite complex. The most difficult and time-consuming job is to find the source of a fault when it occurs. Correcting the fault is easy if the source is found. CNC service engineers know this from experience. In a CNC machine, there are hundreds of cables and connections; even one bad contact may put the machine into the alarm state. The computer in CNC machines consists of hardware and software. The address of each bit in the diagnostic table is defined by its row and column numbers. As shown, the latest conditions of the CNC are represented by bits in the diagnostic table. Real relays were given as examples but the diagnostic table also contains logical relays. Expert systems were first introduced with the concept of artificial intelligence and since 1970 have been applied successfully in medical diagnosis, chemical analysis, and design of computer system configurations.
