Siemens servo drive
The servo system is one of the most important components of CNC machine tools. It is the link between the CNC device and the execution components. It converts the digital signal sent by the CNC device into the direction and speed that meet the predetermined requirements. , position movement[]. The performance requirements of CNC machine tools for feed servo systems include: positioning speed and contour cutting feed speed, positioning accuracy and contour cutting degree, surface roughness of finishing, stability under external interference, etc. These requirements mainly depend on the static and dynamic characteristics of the servo system. For example, in order to ensure the contour shape accuracy, in addition to requiring the machine tool to have high positioning accuracy, the servo system is also required to have good dynamic response characteristics and be able to follow the command signal stably and flexibly. , that is, the system is required to have high contour following accuracy, which is related to the stable and dynamic characteristics of the machine tool servo drive system, and these characteristics depend on the main parameters of the feed servo system, such as current loop gain, current loop integration time, and speed loop gain. /, speed loop integration time/etc. The above parameters have been set when the CNC system leaves the factory, but they do not completely match the actual working conditions of the CNC machine tool, such as the drag of actual mechanical parts during processing. Therefore, parameter adjustment and optimization need to be carried out to improve the performance of the CNC machine tool. Parameter adjustment and optimization are divided into two methods: manual and automatic. Manual adjustment and optimization have higher requirements on debugging personnel and are difficult to master. Automatic adjustment and optimization have the advantages of simplicity and speed, and are easy to master quickly.
Configuration of servo drive
._Servo debugging tool_
The servo debugging tool is a soft tool developed by Siemens for debugging. It is intuitive, fast and easy to hold. _The main screen of the servo debugging software is as shown in the figure. It can set the basic parameters matching the driver, motor and power module. It can automatically adjust and optimize the parameters of the speed controller according to the mechanical parts actually driven by the servo motor, and can monitor The operating status of the servo drive, such as the actual current and actual torque of the motor, etc.
._The connection between the software and the drive is powered off. Use the R3 cable to connect the interface to the port on the drive, and then power on the drive. The LCD window shows that there is no data in the Bios drive, the R/red light is on, and the red light on the bus interface module is on. At this time, you can find the driver debugging tool
_ software from the start and start it. .3 Servo drive basic parameter setting When using
_ to set parameters, you must follow the following steps:. Start the_software, select the online mode, search for the online driver (rr) b. Name the driver to be debugged, and then After selecting Next to enter the online mode, automatically identify the models of the power module and control board, then select Next to enter the motor model, such as 3- and then select Next. Select the type of encoder according to the motor model. Select speed control mode (/), and then select Next._ List the selected data. If the data is correct, select to accept the axis driver configuration () Note: If this is an application that has not yet been debugged, the driver’s enable signal will not take effect, and the motor Cannot rotate. After the function takes effect (that is, the driver enable control takes effect), and the near feed axis parameters (and) are set, the feed axis can be moved and the dynamic characteristics of the feed axis can be optimized
. Servo drive parameters Optimization
After completing the settings of the servo drive, it is necessary to adjust the dynamic characteristics of the speed loop of the servo drive before debugging the position loop. The speed loop dynamic characteristics optimization of Siemens/AC servo drives can be automatically performed through the software. The speed given for optimizing the drive is given digitally by the machine and does not need to be controlled. The steps for dynamic optimization of the drive speed loop are as follows:
Use the drive adjustment cable to connect the debugging computer to the interface. If it is necessary to optimize the motor with braking, the corresponding general parameters should be set, such as:, the bit of [] is (restored to after optimization is completed)
b
Turn on the enable of the driver signal (power module terminal, 3 and AND connected), and move the coordinate axis to the middle position of the workbench, because when the drive is optimized, the motor will automatically Turn about two turns to start the tool software_, select the online mode, then select the control mode, and confirm. Select the controller subdirectory in the pop-up dialog box, and then select again to pop up the speed control screen
Select automatic speed controller optimization to pop up the parameter loop optimization screen. Select ~ step to automatically execute the optimization process: analyze mechanical characteristics one (the motor rotates forward, the brake with the brake motor should be released) analyze the mechanical characteristics two (the motor rotates reversely, the brake with the brake motor should be released) current loop calculation ( The motor is stationary and the brake with the brake motor should be clamped) Parameter optimization calculation
_The software controls the CNC system and CNC machine tools to complete the automatic optimization of parameters within a few minutes. It is fast and simple and can be easily used by the majority of users. The CNC machine tool debugger holds that the optimized parameters are in line with the actual working conditions of the CNC machine tool, and can effectively improve the dynamic characteristics of the servo drive, thereby improving the machining accuracy of the CNC machine tool
Among them, the workpiece clamp is loosened to open the work The area loading door is the coordinate value of the stop position of the axis when the truss robot grabs the workpiece. This machine tool sets the second reference point of the axis as the stopping position when the truss robot grabs the workpiece, and the position of the second reference point is stored in the parameters. Enter the coordinate value of the axis into the parameter
Conclusion
As market competition intensifies, the demand for products increases, and CNC machine tools with high precision, high productivity, flexibility, multiple varieties, and short cycles are required. And its automatic production line is impacting the traditional combined machine tool production line. Therefore, improving the working efficiency of CNC machine tools in the entire production line has become the key to the development of future production lines. Among them, improving the communication speed and stability between CNC machine tools and peripheral equipment will also become the development direction of CNC machine tool production line technology in the future.
Siemens servo drive maintenance