The SINUMERIK 810M CNC system of the Φ160 horizontal boring and milling machine consists of a CPU module, a position control module, a memory module, a text and graphics processing module, a CRT display, an interface module, an I/O module and an operation panel. It is a channel-type CNC system that transmits data through an RS232C interface. 1 Analysis and troubleshooting of common faults in the Siemens SINUMERIK 810K system (1) CPU monitoring alarm. If this alarm light is on, the system cannot be started and the CNC system is in a fault state. The cause of the fault can be found from the following aspects: incorrect connection of the jumper terminal in the CPU module; EPROM memory failure; bus board damage; machine tool parameter error; startup chip damage. If the CPU monitoring alarm occurs during operation, it is mostly due to module hardware failure or CPU loop operation error; (2) EPEOM memory self-diagnosis alarm. When this alarm occurs, it is rare for the EPROM memory to be actually damaged. Instead, it is mostly caused by poor insertion of the memory module or EPROM chip and incorrect insertion position; (3) Data memory sub-module low battery voltage alarm. When this alarm occurs, the battery must be replaced while the system is powered on, otherwise the machine tool data and PiE control program will be lost. Therefore, after the machine tool is adjusted, the machine tool data and PiE control program should be backed up and stored on a floppy disk. Once the machine tool data and PLC control program are lost, the computer should be connected to the serial port of SINUMERIK810K using the transmission software for transmission; (4) Corridor monitoring alarm. This indicates that the actual moving speed of the coordinate axis is higher than the allowable value of the specified corridor monitoring threshold speed, or that the corresponding reference axis cannot reach the required speed within the specified time when it is at high speed or braking. This is mostly caused by improper KV coefficient setting. Or the position feedback cable and pulse encoder are faulty. Or it is caused by excessive mechanical clearance; (5) Position feedback loop hardware failure. This indicates that the detected position feedback signal has a phase error or a ground short circuit or no signal at all. It can detect whether the position loop cable is broken; check whether the position module is faulty; use an oscilloscope to measure the phase of the position feedback signal to determine whether the cable and position sensor are faulty. 2. Faults on Φ160 horizontal boring and milling machines causing machine tool failures (1) Machine tool runaway (i.e., runaway). This type of fault occurs when installing and adjusting the machine tool. The cause is mostly abnormal position or speed detection signals, or broken wires or reversed polarity, resulting in positive feedback. If it occurs suddenly during machine tool operation, it is mostly due to the signal feedback line being pulled apart by the movement of the machine tool, or a fault in the control board and feed servo speed control unit of the CNC system; (2) Machine tool vibration. In addition to large mechanical clearance or poor hydraulic lubrication, the cause of vibration should be checked to see if the settings of the position control and speed control unit are correct, and to analyze whether the machine tool vibration cycle is related to the feed speed. If it is not related to the feed speed, it is mostly due to the speed loop gain of the axis being too high. If it is related to the feed speed, it is mostly due to the position detection gain being too high, and the position detection gain needs to be adjusted; (3) Poor machining accuracy of parts. This is mainly because the symmetry of the dynamic tracking error value between each axis is not adjusted to the best state, or the transmission chain of each axis of the machine tool changes after a period of use. 3. Methods for fault diagnosis of CNC machine tools (1) The PLC control program of Φ160 horizontal boring and milling machine sets more than 100 alarm processing information for the machine tool. SINUMERIK810M has hundreds of alarm information. The root cause of the fault is found according to the prompts of the alarm content; (2) Improper principle analysis. According to the composition principle of CNC system, the characteristics of each point can be analyzed logically and the measurement comparison can be carried out to locate the fault; (3) Equivalent substitution method. Use the existing spare board for equivalent substitution, and then repair the faulty board after replacement; (4) Partial isolation method. The idea of ​​this method is to regard the machine tool as a "building block". Each "building block" is independent and connected. The composition of the control system is similar. Remove a part and observe the phenomenon that occurs. Because the signal of the faulty part is absent or abnormal, the fault point can be judged from the changed phenomenon; (5) Measurement comparison method. The printed circuit board of CNC system is generally equipped with terminals for detection. Measure the voltage and waveform of the terminals, and analyze the cause of the fault and the location of the fault in combination with the working principle. [b][align=center]For details, please click: Troubleshooting Common Faults in the CNC System of a Φ16O Horizontal Boring and Milling Machine[/align][/b]