CNC machine tool fault diagnosis technology - Solutions - Huaqiang Electronic Network

Single chip microcomputer STM32L151CCU6

CNC systems are high-tech intensive products. Diagnostic techniques are needed to quickly and correctly identify the cause and determine the location of the fault. With the continuous development of microprocessors, diagnostic techniques have evolved from simple diagnostics to versatile advanced diagnostics or intelligence. The strength of diagnostic capabilities is also an important indicator for evaluating the performance of CNC systems. The diagnostic techniques of the various CNC systems currently in use can be broadly classified into the following categories:
1. Start diagnosis Start diagnosis means that the CNC system automatically performs diagnosis every time the power is turned on from the system. The diagnostic content is the most critical hardware and system control software in the system, such as CPU, memory, I/O and other unit modules, as well as MDI/CRT units, tape readers, floppy disk units and other devices or external devices. Only when all the items are confirmed to be correct, can the entire system enter the normal preparation state. Otherwise, the fault message will be indicated on the CRT screen or LED with an alarm mode. At this point, the start-up diagnostic process cannot be completed and the system cannot be put into operation.
2. Online diagnosis Online diagnosis refers to the automatic installation of the CNC system itself and the various servo units, servo motors, spindle servo units, spindle motors and external devices connected to the CNC device through the built-in program of the CNC system. Diagnosis, inspection. Online diagnostics will not stop as long as the system does not lose power.
Online diagnostics generally include thousands of status displays of the self-diagnostic function, often displaying their status in binary 0 and 1. For positive logic, 0 means the off state, 1 means the on state, and the status display can determine the location where the fault occurred. Commonly used interface status and internal status display, such as using I / O interface status display, combined with plc ladder diagram and strong electric control circuit diagram, using the inference method and exclusion method to determine the true location of the fault point. Most of the fault information appears in the form of an alarm number. Generally can be divided into the following categories: overheat alarm class; system alarm class; storage alarm class; programming / setting class; servo class; travel switch alarm class; connection fault between printed circuit boards.
3. Offline Diagnostics Offline Diagnostics After the failure of the index control system, the CNC system manufacturer or professional service center uses dedicated diagnostic software and test equipment for downtime (or offline) inspection. Try to locate the fault to the smallest possible range, such as shrinking to a functional module, some part of the circuit, or even a chip or component, this fault location is more accurate.
4. Modern Diagnostic Technology With the development of telecommunications technology, the cost performance of IC and microcomputer has increased. In recent years, some new concepts and methods have been successfully cited in the field of diagnosis.
(1) Communication diagnosis is also called remote diagnosis, that is, the telephone communication line is used to test and diagnose the faulty CNC system and the dedicated communication diagnosis computer of the professional service center through connection. If Siemens uses this diagnostic function in the diagnosis of the CNC system, the user connects the dedicated "communication interface" in the CNC system to the ordinary telephone line, and the "dataphone" of the dedicated communication diagnostic computer of the two subsidiary service centers. It is also connected to the telephone line, and then the computer sends a diagnostic program to the CNC system, and the test data is returned to the computer for analysis and conclusion, and then the diagnosis conclusion and processing method are notified to the user.
The communication diagnosis system can also make regular preventive diagnosis for the user. The maintenance personnel do not have to visit the site, and only need to perform a series of operation inspections on the machine tool according to the scheduled time. The diagnosis data can be analyzed in the maintenance center, and the hidden troubles can be found, so as to be early. Take measures. Of course, such CNC systems must have a remote diagnostic interface and networking capabilities.
(2) The self-repair system is equipped with a spare module in the system, and a self-repair program is installed in the software of the CNC system. When a certain module is found to be faulty when the software is running, the system displays the fault information on the one hand. On the CRT, it automatically finds whether there is a spare module at the same time. If there is a spare module, the system can automatically take the fault offline, and the standby module can be turned on to make the system enter the normal working state quickly. This solution is suitable for unmanaged automated workplaces.