1. Visual inspection method It is the first method that maintenance personnel use, that is, from the outside to the inside, one by one during the fault diagnosis. Special attention should be paid to observing the components and circuits of the circuit board for signs of burns, cracks, etc., whether the circuit board is short-circuited, broken, or poor contact with the chip. For circuit boards that have already been repaired, attention should be paid to missing parts or errors. Parts and disconnections.
2. Function Program Test Method The function program test method is to program the G, M, S, T and F functions of the CNC system into a functional test program and store them on the corresponding media such as tapes and tapes. Running this program during a fault diagnosis can quickly determine the possible cause of the fault.
The function program test method is often used in the following cases: 1) The machine tool processing causes the waste product and cannot be determined at one time whether the programming operation is improper or the CNC system is faulty. 2) The CNC system has a random fault. It is difficult to distinguish between external disturbances and poor system stability. 3) When CNC machines with long idle times are put into use or when they are regularly overhauled, the trial exchange method is to analyze the general cause of failures. Maintenance personnel can replace doubtful parts with spare printed circuit boards, integrated circuit chips, or components to narrow the fault down to the printed circuit board or chip level.
Before using this method, please pay attention to whether the setting status of the standby board is exactly the same as that of the original board. This includes the selection switch of the check board, the setting position of the short bar, and the position of the potentiometer. Generally do not put the CPU board and memory board more easily, otherwise it may cause the loss of the program and machine parameters, resulting in the expansion of the failure; if the EPROM board or EPROM chip, please pay attention to whether the software version label attached to the memory chip is exactly the same as the original board. If it is inconsistent, it cannot be replaced.
4. When the parameter inspection method fails, check the system parameters in time. The parameters are usually stored in the bubble memory or in the CMOS RAM that needs to be held by the battery. Once the battery is insufficient or due to external interference and other factors, the individual parameters are lost or changed. The chaos occurred and the machine did not work properly. At this point, you can troubleshoot by checking and correcting parameters.
5. Measurement and comparison method When designing a printed circuit board, a manufacturer of a CNC system has designed a number of test terminals on a printed circuit board for ease of adjustment and maintenance. The maintenance personnel can check whether the working status of the circuit is normal by detecting the voltage or waveform of these measurement terminals. However, before using the test terminals for measurement, you should familiarize yourself with the function of these test terminals and the circuit or logic of the relevant parts.
In addition to the above-mentioned commonly used fault detection methods, it is also possible to use a tapping method to check whether the welding or poor contact or the like. In short, according to different fault phenomena, several methods can be selected at the same time for flexible application and comprehensive analysis, so as to gradually narrow the fault range and eliminate the fault faster.
