Case Study: Improving Labeling Efficiency by Optimizing Configurations of SINAMICS S200 Servo Systems
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Copyright and Tribute: This article is contributed by Shenghui You who is the Chief Motion Control and Servo System Engineer at SIEMENS China. As a SIEMENS OEM partner, ELITER Packaging Machinery greatly appreciates their ongoing support in providing control system solutions for our packaging machines. Any unauthorized copy or infringement against the content within this article will lead to legal issues.
Shenghui You
Chief Motion Control Engineer at SIEMENS
About the Author
Shenghui You, Chief Engineer at SIEMENS, author of “Application Guide to Motion Control Systems“, is an expert in motion control and automation.
You has prestigious academic trajectory and has extensive experience in research projects and research publications. His research focuses on motion control algorithms, intelligent control systems, and new sensing technologies. Active in international conferences,
You shares his innovative work widely and his works have been the key resource for engineers and researchers, and his contributions are highly valued in both academia and industry.
Preface and Introduction to the Case Study
The SINAMICS S200 servo drive system is a single-axis AC/AC servo drive system that is compact, highly dynamic, easy to use, and robust, suitable for various motion control applications in the standard servo motion market. It includes the SINAMICS S200 servo drive, SIMOTICS S-1FL2 servo motor, MOTION-CONNECT 350 and 380 cabling systems, and various configuration tools. The SINAMICS S200 servo drive includes versions with PROFINET bus and PTI pulse drive.
SINAMICS S200 Servo Drive System
Credit: SIEMENS
This article introduces the debugging and optimization of the S200 PTI servo drive in the application of high-speed labelling machines. Labelling machines commonly require the servo to achieve rapid point-to-point positioning, high repeat positioning accuracy, and positioning without overshoot. In most cases, the one-click optimization feature of the S200 servo drive can meet the application needs of the machine. However, due to the complexity of on-site equipment conditions, the effect of one-click optimization may not always be satisfactory. In such cases, manual fine-tuning can be performed.
The circumstances described in this article apply to machines with the following mechanical characteristics:
- Insufficient mechanical stiffness, such as those using belt transmission or a combination of gears and belts.
- Large inertia of the load and motor (greater than 4).
Introduction to High-Speed Labelling Machines (Label Dispenser)
A high-speed labelling machine is a device that adheres adhesive paper labels (either paper or metallic plastic foil) from a roll onto a PCB, product, or specified packaging. Despite its simple structure, it demands high dynamic performance from the servo system to achieve precise positioning in a short period.
A labelling machine typically includes one or two labelling servos (0.75 kW). Given that high-speed labelling machines are typical applications of belt transmission, this article will use an actual high-speed labelling machine (figure shown below) as an example to introduce the debugging and optimization methods of the S200 PTI servo drive.
CAB IXOR Label Dispenser
Credit: CAB
Operation Sequence of High-Speed Labelling Machines
The labelling machine usually comes with an integrated conveyor that when the machine is set to operation status, the conveyor belt moves the objects forward. When the object sensor detects an object, the PLC sends a fixed number of pulses to the servo (the number of pulses can be adjusted on the touchscreen).
The servo starts and feeds the label. Once the label’s colour mark sensor detects the gap between labels, it sends a rising edge signal to the PLC to trigger an interrupt, and the servo output immediately stops. The below figure illustrates the labelling control process.
Operation Principle of Labelling System
Electrical Components and Control System of High-Speed Labelling Machine
The blow chart shows the electrical components engaged in the labelling machine’s control system
Software, Control System and Components
Configuration and Optimization with Servos
Configuration Methods
Since labelling machines are typical high-dynamic response belt applications, it is necessary to maximize the closed-loop gain while turning off the torque feedforward and disable the current notch filter to avoid unnecessary filter settings. The one-click optimization in the debugging panel cannot meet the requirements and requires manual adjustment of the one-click optimization parameters.
- If only simple debugging is needed after completing the one-click optimization, Method 1 can be used.
- If the application requirements are higher and precise calculations and curve recording are necessary, a combination of one-click optimization and online optimization can be used, referred to as Method 2.
The overall flowcharts for the two optimization methods are shown in the below chart:
Servo Drive Quick Configuration
A user-defined table of parameters is created for optimization of configurations based on the actual case of application.
The following configurations are supposed to be added into the table:
- P5271=1100B: Set for online optimization; one-click optimization configuration; disable torque feedforward.
- P5292=125%: Set the dynamic coefficient for speed loop gain in FFT optimization, enhancing the closed-loop gain.
- P5301=101B: Set proportional gain Kp=1; set current setpoint filter=0; evaluation variable=1; determine inertia based on frequency characteristics; disable settings for the current notch filter.
- P5308=360°: Set the one-click optimization running distance, mindful of the actual mechanics, and be cautious of impacts.
- P5300=1: Enable one-click optimization.
Remove or don’t install the label tape roll, enable servo for one-click optimization, and after servo movement, P5300=0 indicates that the optimization is complete.
Implementation of Method 1
Method 1 is one of the approaches to finish the work after the completion of servo quick configuration.
Add P29178 to the tablet, and it is recommended to set it to half of the default value after one-click optimization to reduce overshoot and vibration.
Add P29174 to the list, and it is recommended to set the speed feedforward factor to 90% to reduce position overshoot.
Add P29283 to the list, this parameter affects the acceleration and deceleration time. In this case, set P29283[01] to 0MS, P29283[11] to 8MS.
Add P1460, speed loop P gain, to the list and maximize P1460 until motor vibration occurs to improve dynamic response. It is also recommended to scale P1462 and P1433 proportionally; for example, if P1460 is set to twice its original value, then set P1462 to the original P1462 times 12, and P1433 to the original P1433 times 2.
The final step is to install the label tape roll. Test the labelling machine and, if necessary, do some further adjustment to above configurations until the performance reaches the expected level.
Implementation of Method 2
In case that the method 1 does not work to achieve the expected motion performance, method 2 should be adopted after the quick configuration instead of the former.
Set P5302=1000B
Set P5300=2 and activate the online optimization.
Changing the online optimization dynamic coefficient P5272 will result in the recalculation and rewriting of P1460, P1433, P1462, and P29176.
Open Startdrive V19 Beta and add an S200 PTI drive, then add Trace signals.
- Add a new Trace curve: This involves creating a new data visualization or trace curve in the software to monitor specific system behaviors or outputs.
- Open extended parameters: This step instructs the user to access a broader or more detailed set of system parameters, which are likely not visible by default. This allows for more comprehensive configuration or monitoring.
- Add 7 channels: This involves setting up specific channels for monitoring various aspects of the system’s operation. Each channel corresponds to a different system parameter:
- Position: Tracks the position with parameters r29288 and r479[0].
- Speed: Monitors the speed with parameters r29182 and r61[0].
- Torque: Observes the torque through parameters r79[0] and r80.
- Following error: Measures the error in following a set path or target with parameter r29187.
- Set Trace trigger conditions: This final step involves defining conditions under which the Trace (data recording or monitoring) will activate. This could be based on specific thresholds, events, or system states to start capturing data relevant to debugging or optimization tasks.
Click to download, go online and activate trace. Start the labelling machine and servo motion. The following curve will be acquired within the system.
Click on the signal panel, and categorize the set values and actual values together. Zoom and categorize the curves, which are sequentially the set values and actual values of position, speed, and torque, as well as the following error. From the set and actual values of speed, it is evident that the current dynamic response is insufficient.
Adjusting P5272 can improve the dynamic response of the servo. After modifying P5272 to 380%, observe that the actual speed value in the Trace curve has oscillated. It is appropriate to reduce P5272 with a setting range of 5%-1000%.
Increase P5272 by 300%, and observe that while there is still overshoot in the following error, the speed oscillation has decreased. At this point, the response meets the application requirements, so based on this, fix the parameters and continue to reduce the position overshoot.
Disable the enablement and set P5300 to 0 to turn off online optimization and fix the current parameters.
Add P29174, P29178, P29283 to the list.
Set 29283[0] to 6 ms. Prioritize increasing 29283[0] to ensure a smooth acceleration and deceleration while maintaining the beat.
Set P29178 to 5.579, which is recommended to be half of the current value to reduce overshoot and oscillation of the speed and position setpoints.
Set P29174 to 90%. This will suppress position overshoot, making the system more accurate. The peak following error is 1700. When converted to motor angle, 1700/1024/12048*360 = 0.29°. The precision meets the requirements of this high-speed labeling machine.
Key Factors with Regard to the Optimization
The choice of trace settings is one of the key factors.
When using the waveform recording function of STARTDRIVE, it is recommended to record the following 8 groups of signals:
- R29288: Recording the value of filtered pulses set in the system, which likely helps in monitoring the accuracy and consistency of the pulses that control motion or operations.
- r479[0] and r479[1]: These parameters are used to record actual positional values from different encoders attached to the system. r479[0] refers to the actual position value from the motor encoder, and r479[1] captures the same from a secondary encoder. This dual recording helps in diagnostic comparisons and ensuring encoder accuracy.
- r29182: This records the total set value for speed, allowing operators to track if the system is reaching its desired speed settings.
- r61[0]: It records the actual speed value without any filtering. This raw data is crucial for understanding the real-time dynamics of the system, especially under varying load conditions.
- r79[0] and r80: These parameters are concerned with torque, with r79[0] recording the set value and r80 recording the actual value. Monitoring both set and actual torques is essential for analyzing the system’s ability to deliver mechanical force under different operational states.
- r29187: This records the positional following error, an important metric in systems where precision in following a designated path or position is critical. It helps in diagnosing issues with system accuracy or in tuning the system to minimize errors.
Key Parameters for the Labelling System Optimization
P29283[0] affects the overall response of the motion, increasing its value will extend the acceleration and deceleration time, but will make the system more stable. For labeling applications, to meet the total response time requirement, the acceleration/deceleration time (p29283[0]) can be increased as much as possible based on the label length, but setting it too high may result in missing labels.
For example, if the line speed V=50m/min and the label length=10mm, then the total deceleration time is: p29283[0] + p29283[1] + p29176 =10/50*60=12ms
Wrap-Up of the Case Study
The 200 PTI servo drive can meet various speed requirements for labeling applications, demonstrating exceptional performance with its fast current control. Advanced control algorithms enable precise positioning and quick responses, making labeling more accurate and stopping quicker; intelligent fault diagnosis and protection functions ensure stable operation of the equipment; the simple and user-friendly interface allows users to easily configure settings.
