Keywords: CNC machine tool system data protection, backup and recovery
Chinese Library Classification Number: TG659 Document Identification Code: A
CNC machine tool system data protection and backup and recovery
YAN En-gang
Abstract: Data from CNC machine tools serves as the medium for matching between the system and the machine tool, as well as between the system and the servo drive. It not only handles the setting of relevant parameters between the system and the machine tool,
This encompasses the implementation of system data exchange functions. It is essential data supporting system operation and crucial for the machine tool to achieve its performance goals. Once this data is lost, the machine...
The machine tool will lose its original control, triggering various malfunctions and causing unnecessary losses. By establishing machine tool data backups, the normal operation of the machine tool can be quickly and effectively restored.
This article illustrates the protection and backup recovery of system data through examples, and analyzes and studies its application.
I. Overview
CNC machine tools are crucial for machining key components in the industrial sector, and most companies consider them critical equipment requiring intensive maintenance. Establishing machine tool data backups is an indispensable and essential step for users, and it's also one of the mandatory technical documents provided by machine tool manufacturers for CNC machine tools. During the use of CNC machine tools, data loss is highly unpredictable; factors such as sudden power outages and surges during operation, malfunctions of the system motherboard or storage modules, and the depletion of energy in capacitors maintaining high energy levels in the system's static memory all contribute to data loss. External interference, misoperation, and the effects of temperature and humidity changes on the system board are also significant causes of data loss, leading to machine tool malfunctions. Therefore, establishing CNC machine tool system data backups, implementing data protection measures, and recovering lost data through backups to restore machine tool functionality are essential long-term tasks for machine tool users.
II. Case Study on System Data Protection, Backup and Recovery
After a machine tool is debugged, the following data needs to be backed up: machine tool data, pitch error compensation, test run data, PLC logic control program, user alarm text, etc. Test run data includes: backlash compensation for each axis, soft limit of coordinates, lead screw pitch error compensation, driver data, etc. Machine tool data is set at the factory. The data backup process is the process of protecting system data; therefore, how to protect the backed-up machine tool data becomes a very important issue. In practical applications, the following problems often occur: due to insufficient understanding of machine tool data and its function, machine tool data is arbitrarily modified, resulting in changes to the original backup data, and the CNC machine tool cannot perform its original function; also, improper storage of the data backup disk (or CF backup card) causes the data medium to fail or be lost, making the data backup unusable if the machine tool malfunctions; failure to provide complete system data backup files during acceptance testing renders the machine tool unusable when data is lost; and incomplete technical documents such as drawings and manuals provided by the manufacturer, and the lack of information on system password settings, prevent access to the system data setting state, etc. Therefore, understanding the role of machine tool data, protection methods, and recovery through backup after loss is very important and a prerequisite for ensuring the normal operation of CNC machine tools.
Application Example 1
The CKW61125/5M CNC lathe adopts the SIEMENS 802D system, featuring AC servo control for the spindle with stepless speed regulation, and SIEMENS 611 AC servo drives for the machine tool feed axes. It is equipped with a linear encoder for closed-loop position adjustment, electronic handwheel feed, a four-position automatic rotary tool turret, a SIEMENS S7-300 PLC logic controller, and a PROFIBUS interface. The machine tool is equipped with a centralized lubrication and cooling system.
During machine tool operation, alarm 510018 occurred, indicating ROV feed rate and FST axis feed prohibition. The MMC and OP (OP031) human-machine interface boards were not functioning. The auxiliary functions of the machine tool control panel, such as spindle start/stop and cooling, were working normally in manual mode. Pressing and holding the reset button allowed for homing and X/Z axis feed operations.
Cause Analysis and Recovery: Based on the phenomena observed by the machine tool, the data communication between the NC system and the MMC and OP boards entered a dead loop. The axis feed prohibition meant that the drive axis was not enabled. Alarm number 510018 was diagnosed as a channel alarm. Initially, a hardware problem was suspected, specifically a data communication failure between the MMC and OP boards. The MMC and OP (OP031) communication boards were replaced, and the NC system mainboard was also replaced. However, the problem persisted after these replacements, remaining unchanged from its original state.
Based on the above handling, the following measures were taken: ① Feed enable test: After pressing "Feed Start", alarm S510118 was cleared, but alarm 700132 appeared, indicating a lack of feed enable. ② "Cycle Start" test: alarm 10203 (channel 1) appeared, indicating no reference axis. ③ JOG test: alarm 5100088 was displayed. ④ Spind Start test: alarm 600308 was displayed. ⑤ Calling machine tool data Data-(x, z, c), All.Data, and PLC programs could not enter the setting state.
The test results showed that the alarm could not be cleared, and alarm numbers 5100088 and 600308 were outside the diagnostic range.
The analysis suggests that the machine tool system data files were lost.
Measures taken and recovery methods: Using the machine tool system data backup files, the machine tool Data-(x, z, c), All.Data data, and PLC program files were re-processed.
Transmission method: Use the 802D WinPCIN system communication software to transfer machine tool data files between the NC system and the RS232 interface via Toolbox→WinPCIN.
(1) Data transmission: ① Configure Data1→RS232 interface: Set the communication interface (comm Part), select COM2; set the baud rate (Baudrate) to 9600; select Data bits to "8"; select stop bits to 1; select hardware (RTS/CTS). ② Complete the transmission of MD2→Data1 using "Drive 1 Drive X Drive Z". ③ Format selection: For 802D, select binary data format; for WinPCIN, select binary data format → start data reading.
(2) PLC program transmission and status settings. Select "Simatic Manager" → "aptians" → "pc Adapter (MPI) (display)" → "properties" → "status" in sequence. Among them, "PG/PC is the only machine on the bes" is not selected; "Address" is selected as "0"; "Time-out" is selected as "30S"; "Transmission Rate" is selected as "187.5kbps"; "Highest Station Address" is selected as "63"; terminal 7 is set to "+24V" and terminal 15 is set to "0V".
After setting the data as described above and transferring the machine tool data backup file, restart the machine. All alarms on the machine tool will be cleared. At the same time, perform the following trial run and processing.
(1) Return to the reference point and reset and adjust as follows.
Startup → Machine Data → Axis Parameters
34100→X→0; 34100→Z→1;
The first reference point is set at X + 502 Z + 40; the second reference point is set at X + 502 Z + 3480.
(2) Adjustment of machine tool limit.
X-axis: 10720 alarm; setting bits 36100, 36110; Z-axis: 16621 alarm; setting bits 36100, 36110, 36120, 36130;
(3) If the G54 offset setting problem occurs during workpiece machining, follow these steps to set it: G54 menu → zero offset → zero offset reference → modify parameter settings.
After performing the above steps, the CNC system was restarted and the machined parts were tested. The machine tool was then fully restored to normal operation.
Application Example 2
The CKW61100/3M CNC lathe uses a SIEMENS 802D system, featuring AC servo drive for machine feed and fully closed-loop control. The spindle achieves stepless speed regulation via gear transmission. The machine tool employs a SIEMENS S7-300 PLC logic controller to meet the system's control functions. It features a four-position electric rotary tool turret and includes a 10.4” CRT monochrome display, graphic display, tool compensation, fault diagnosis, simultaneous machining programming, and a PROFIBUS interface.
During machine tool operation, the following issues occurred: ① All indicator lights on the MCP panel flashed. ② The MMC and OP boards displayed normally, but a PLC ON Start alarm appeared. ③ The PLC/OUT output was not displayed, but the PLC/INPUT input was displayed. ④ The feed and spindle did not move, but indicator lights showed alarms. ⑤ The OP board connector showed signs of burning, but after inspection, the connection and communication were found to be normal.
Cause Analysis and Recovery: Although there were no system alarm prompts, the fault symptoms were quite obvious. The indicator lights on the machine tool's control panel were flashing, indicating a problem with its NC communication. The PLC, F-feed, and spindle S-functions were malfunctioning. Analysis suggested that the fault was related to the PLC program and machine tool data. Since the system status prevented the retrieval and adjustment of machine tool data parameters, the method of retransmitting the machine tool data backup file was adopted. The relevant settings and transmission were the same as in Application Example 1.
After taking the above measures, the machine tool malfunction was eliminated, but the following problems remained: ① The spindle could not run. ② The tool T function was abnormal. ③ There was a problem with the limit switches. ④ The G54 offset setting had the same problem as in Application Example 1. The following data settings were modified: the tool T, spindle (Smin/Smax), and (X, Z) axis limit switch function parameters were reset. After modification, the T function, spindle S function, and (X, Z) axis limit switch functions returned to normal, and the G54 offset setting was the same as in Application Example 1. After completing the above work, the machine was run again for testing, all machine tool reports disappeared, and the machined parts were completely restored to normal operation.
As can be seen from Application Examples 1 and 2, although the phenomena observed by the machine tools differed, the root cause of the problem was data loss in the machine tool system. The two machine tools were located in two different places, both in a hot and humid southern region, and both operating during the hottest season. During the handling of both application examples, a common problem was also revealed: the system data backup files were incomplete, and the retransmitted files differed from the actual operating status, requiring readjustment. In one case, the data backup for one machine tool failed due to improper storage and a faulty data medium, necessitating a remote retransmission. This highlights the limitations of CNC systems in adapting to high-temperature and high-humidity environments, and the resulting impact on the system and machine tool operation. Therefore, the user unit needs to take necessary measures and preventative measures.
III. Conclusion
The protection, backup, and recovery of CNC machine tool system data is an indispensable task for CNC machine tool application companies. With the increasing prevalence of CNC machine tools, understanding the role of system data and methods for protection and recovery is crucial. It is key to ensuring the normal operation of CNC machine tools, accurately identifying and quickly resolving problems in machine tool applications, ensuring safe and reliable operation, and improving equipment utilization. This also reflects that only through the rational and correct application of CNC machine tools can the system be made safer and the machine tool operation more reliable.
