PLC control method, device, electronic equipment and storage medium for unwinding of extra-large rolls

Abstract

This application provides a PLC control method, device, electronic equipment, and storage medium for unwinding ultra-large rolls. Applied to the field of automation control technology, it acquires roll information and linear speed in real time during the unwinding process, dynamically calculates the required motor speed and frequency, and performs closed-loop control. This effectively solves the problems of insufficient control accuracy and unstable operation caused by fixed parameters in existing technologies. Therefore, it can achieve real-time, dynamic, and precise control of the ultra-large roll unwinding process, effectively solving problems such as linear speed fluctuations, tension loss of control, strip damage, and unstable motor operation caused by fixed parameters in existing technologies. This significantly improves the safety, continuity, and production efficiency of unwinding.

Description

Technical Field

[0001] This application relates to the field of automation control technology, and in particular to PLC control methods, devices, electronic equipment and storage media for unwinding ultra-large rolls. Background Technology

[0002] With the rapid development of e-commerce, logistics, and manufacturing, the use of strapping (PP, PET, steel strapping, etc.) in pallet and box bundling has increased exponentially. To reduce the frequency of roll changes and improve the overall production line cycle time, upstream extrusion / stretching equipment has generally been winding finished strip materials into ton-level vertical ultra-large rolls.

[0003] However, most existing unwinding devices and their PLC control methods follow the traditional design concept of small and medium-sized rolls, which seriously restricts the safe, continuous, and accurate unwinding of ultra-large rolls.

[0004] In existing technologies, most PLC programs estimate the rotational speed using fixed roll diameter or segmented lookup table methods, lacking a closed-loop update mechanism based on real-time counting. This results in large fluctuations in linear speed, uncontrolled tension, and the strip being easily broken or stacked. Furthermore, due to drastic changes in roll diameter, and the fact that parameters such as motor reduction ratio and rated speed are often hardcoded in the program, the system cannot automatically correct the motor target frequency based on the real-time roll diameter. This leads to insufficient torque at low speeds, overspeed alarms at high speeds, and frequent emergency stops of the equipment, severely impacting production efficiency.

[0005] Therefore, there is an urgent need in the market for a PLC control method that can acquire drum information in real time and accurately calculate motor speed and frequency to meet the needs of high-speed, stable, and automated unwinding of ultra-large rolls. Summary of the Invention

[0006] In view of the shortcomings of the prior art, this application provides a PLC control method, device, electronic equipment and storage medium for unwinding ultra-large rolls, which is applied to the field of automation control technology. It can realize real-time, dynamic and precise control of the unwinding process of ultra-large rolls. It has the advantages of effectively solving the problems of linear speed fluctuation, tension loss, strip damage and motor instability caused by fixed parameters in the prior art, and significantly improving the safety, continuity and production efficiency of unwinding.

[0007] Firstly, a PLC control method for unwinding an ultra-large roll, the method comprising the following steps:

[0008] S1: After starting the unwinding machine, check if the unwinding position of the drum on the unwinding machine is abnormal;

[0009] S2: If there is no abnormality in the unwinding position of the roll, start the unwinding machine and obtain the roll information of the packing strap and the unwinding linear speed of the packing strap;

[0010] S3: Calculate the drum rotation speed based on the drum information and the unwinding linear speed;

[0011] S4: Obtain the motor reduction ratio, and calculate the required motor speed and frequency based on the drum speed;

[0012] S5: Control the operation of the motor according to the required speed and frequency of the motor, thereby controlling the unwinding machine to unwind.

[0013] This application provides a PLC control method for unwinding ultra-large rolls. By performing anomaly judgment before the unwinder starts, and after normal start-up, based on the acquired roll information and unwinding linear speed, combined with the motor reduction ratio, the required speed and frequency of the motor are accurately calculated, thereby controlling the motor operation to achieve stable and precise unwinding of ultra-large rolls. This avoids the linear speed fluctuation and control instability problems caused by fixed parameters or inaccurate estimation in traditional methods.

[0014] Furthermore, the method also includes the step of:

[0015] S6: During the unwinding process of the unwinding machine, the reading of the photoelectric detection counter is acquired in real time;

[0016] S7: Calculate the real-time update information of the roll based on the reading and the roll information;

[0017] S8: Calculate the real-time updated rotational speed of the drum based on the real-time update information and the unwinding linear speed;

[0018] S9: Calculate the required speed and frequency for real-time motor updates based on the motor reduction ratio and the real-time updated speed of the drum;

[0019] S10: Control the operation of the motor according to the required speed and frequency of the motor in real time, thereby controlling the unwinding machine to unwind.

[0020] This application provides a PLC control method for unwinding ultra-large rolls. By acquiring the readings of the photoelectric detection counter in real time and updating the roll information, it further realizes closed-loop control of the unwinding process and real-time correction of parameters, thereby improving the accuracy and stability of control.

[0021] Furthermore, the drum information includes at least the drum diameter; step S3 includes:

[0022] S31: Calculate the circumference of the drum based on the diameter of the drum;

[0023] S32: The drum rotation speed is calculated based on the drum circumference and the unwinding linear speed.

[0024] This application provides a PLC control method for unwinding ultra-large rolls, which clarifies the specific calculation method of the roll speed, making the calculation of the roll speed more accurate and providing a reliable basis for subsequent motor control.

[0025] Furthermore, the motor drives the unwinding machine through a gear assembly, the gear assembly including a small gear connected to the motor and a large gear meshing with the small gear; step S4 includes:

[0026] S41: Obtain the motor reduction ratio and the number of the first gears of the large gear and the number of the second gears of the small gear;

[0027] S42: Calculate the required motor speed based on the number of the first gear, the number of the second gear, the motor reduction ratio, and the drum speed;

[0028] S43: Calculate the required frequency of the motor based on the required speed of the motor.

[0029] This application provides a PLC control method for unwinding ultra-large rolls, which refines the calculation process of the required speed and frequency of the motor and takes into account the reduction ratio of the gear components, making the motor control more precise and more adaptable.

[0030] Furthermore, step S6 includes:

[0031] S61: During the unwinding process of the unwinding machine, the first exit height of the packing tape at the initial exit moment is obtained, and it is determined whether the first exit height has reached the near end face;

[0032] S62: If the motor reaches the near end face, an end face warning message will be issued and the user will be reminded to reduce the motor speed.

[0033] S63: Determine if the end face unwinding is abnormal. If an abnormality occurs, control the unwinding machine to stop running. If no abnormality occurs, control the motor to run according to the reduced motor speed.

[0034] S64: If the near end face is not reached, obtain the reading of the photoelectric detection counter.

[0035] Furthermore, the roll information also includes roll height, strapping, and strapping thickness; step S7 includes:

[0036] S71: Calculate the number of the first turns of each layer of the packing strap on the roll before unwinding, based on the roll height and the packing strap width;

[0037] S72: Based on the first number of turns and the reading, calculate in real time the number of the second turns remaining in each layer of the packing tape during the unwinding process;

[0038] S73: Calculate the first layer number of packing straps on the roll before unwinding based on the roll diameter and the packing strap thickness in the roll information, and calculate the second layer number of packing straps remaining during unwinding in real time based on the first layer number, the first number of turns and the reading.

[0039] S74: Calculate the remaining second diameter of the drum during unwinding based on the drum diameter before unwinding, the first number of turns, the reading, and the thickness of the packing strap;

[0040] The real-time updated information includes at least the second number of turns, the second number of layers, and the second roll diameter.

[0041] Furthermore, step S7 also includes:

[0042] S75: Obtain the exit direction of the packing tape during the unwinding process, wherein the exit direction includes exiting the tape from top to bottom and exiting the tape from bottom to top;

[0043] S76: When the tape exit direction is from top to bottom, the real-time tape exit height is calculated by subtracting the product of the reading and the width of the packing tape from the first tape exit height;

[0044] S77: When the tape exit direction is from bottom to top, the real-time tape exit height is calculated by adding the first tape exit height to the product of the reading and the width of the packing tape.

[0045] The real-time update information also includes the real-time belt exit height.

[0046] Secondly, a PLC control device for unwinding an ultra-large roll, used to implement any of the methods described above, the device comprising:

[0047] Judgment module: After the unwinding machine is started, determine whether the unwinding position of the drum on the unwinding machine is abnormal;

[0048] Start-up module: If there is no abnormality in the unwinding position of the roll, start the unwinding machine and obtain the roll information of the strapping and the unwinding linear speed of the strapping;

[0049] First calculation module: Calculates the drum rotation speed based on the drum information and the unwinding linear speed;

[0050] The second calculation module obtains the motor reduction ratio and calculates the required motor speed and frequency based on the drum speed.

[0051] Control module: Controls the operation of the motor according to the required speed and frequency of the motor, thereby controlling the unwinding of the unwinding machine.

[0052] Thirdly, an electronic device includes a processor and a memory, the memory storing computer-readable instructions that, when executed by the processor, perform the steps of the above-described method.

[0053] Fourthly, a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the steps of the above-described method.

[0054] Beneficial effects: The PLC control method, device, electronic equipment and storage medium for unwinding ultra-large rolls provided in this application effectively solves the problems of insufficient control accuracy and unstable operation caused by fixed parameters in the prior art by acquiring roll information and linear speed in real time during the unwinding process, dynamically calculating the required speed and frequency of the motor and performing closed-loop control. Thus, it has the advantages of being able to achieve real-time, dynamic and precise control of the unwinding process of ultra-large rolls, effectively solving the problems of linear speed fluctuation, tension loss, strip damage and motor instability caused by fixed parameters in the prior art, and significantly improving the safety, continuity and production efficiency of unwinding. Attached Figure Description

[0055] Figure 1 A flowchart illustrating the PLC control method for unwinding an ultra-large roll provided in this application.

[0056] Figure 2 A flowchart of a PLC control method for unwinding an ultra-large roll provided in this application.

[0057] Figure 3 A schematic diagram of the structure of a PLC control device for unwinding an ultra-large roll provided in this application.

[0058] Figure 4 A schematic diagram of the structure of the electronic device provided in this application.

[0059] Labeling Explanation: 201, Judgment Module; 202, Startup Module; 203, First Calculation Module; 204, Second Calculation Module; 205, Control Module; 301, Processor; 302, Memory; 303, Communication Bus; 3, Electronic Equipment. Detailed Implementation

[0060] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and marked in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0061] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0062] Please refer to Figure 1 , Figure 2 This application provides a PLC control method for unwinding an ultra-large roll, the method including the following steps:

[0063] S1: After starting the unwinding machine, check if the unwinding position of the drum on the unwinding machine is abnormal;

[0064] S2: If there is no abnormality in the unwinding position of the roll, start the unwinding machine and obtain the roll information of the strapping and the unwinding linear speed of the strapping.

[0065] S3: Calculate the drum speed based on the drum information and the unwinding linear speed;

[0066] S4: Obtain the motor reduction ratio, and calculate the required motor speed and frequency based on the drum speed;

[0067] S5: Control the motor operation according to the required motor speed and frequency, thereby controlling the unwinding of the unwinding machine.

[0068] The unwinding machine is equipped with a turntable, on which a vertical extra-large roll is placed. The turntable is connected to a motor and is driven by the motor to rotate and unwind.

[0069] In step S1, the unwinding position of the drum refers to the position where the drum is placed on the turntable. Under normal circumstances, the turntable is provided with a boss mounting structure that matches the drum core. The drum core is fitted onto this boss mounting structure, allowing the drum to be fixed on the turntable and rotate. If the drum is tilted or not installed on the boss mounting structure during installation, and the control system does not recognize a properly installed drum after the start button is pressed, an alarm for abnormal unwinding position installation will be issued.

[0070] The "Start Unwinder" button only indicates that the unwinder has been pressed; it does not guarantee that the unwinder will start normally. After pressing the "Start Unwinder" button, if the unwinding position of the roll is normal, the unwinder will start normally and acquire information about the packing tape roll and its unwinding linear speed. Otherwise, the unwinder will not start and will issue an alarm indicating an abnormal unwinding position.

[0071] The information about the packing strap roll is obtained by scanning a QR code on the packing strap. This QR code stores roll information including, but not limited to, roll diameter, roll height, packing strap thickness, and packing strap width. The unwinding linear speed of the packing strap refers to the desired linear movement speed of the packing strap during the unwinding process. It can be set by the operator or obtained by instructions from the PLC control system, and its main purpose is to ensure that the packing material is output at a constant speed.

[0072] The motor reduction ratio refers to the speed ratio of the gear components that transmit power between the motor and the unwinding machine.

[0073] The core innovation of this application lies in ensuring initial safety by judging abnormal unwinding position before unwinding starts. Based on this, and using the acquired information of the packing tape roll and the desired unwinding linear speed, combined with the motor reduction ratio, the required speed and frequency of the motor are accurately calculated. This achieves precise and stable control of the unwinding process of ultra-large rolls, effectively solving the problems of linear speed fluctuation, tension loss and sudden equipment stoppage caused by inaccurate or fixed parameter estimation in the prior art. It achieves the goal of safe, continuous and precise unwinding of ultra-large rolls.

[0074] Specifically, before starting the unwinding machine, the operator first issues an unwinding command via the start button on the human-machine interface (HMI). Then, vision sensors or multiple photoelectric switch arrays installed at key locations on the unwinding machine scan or detect the unwinding position of the roll to determine if it is correctly mounted on the turntable. If the determination shows no abnormality in the unwinding position, the system starts the unwinding machine and simultaneously acquires the initial physical information of the current packing tape roll and the preset unwinding linear speed. Accurate acquisition of this initial data is the foundation for all subsequent dynamic calculations, ensuring the real-time performance and accuracy of the control. Subsequently, based on the acquired roll information and unwinding linear speed, the system accurately calculates the rotational speed required for the current roll to maintain a constant linear speed. This calculation transforms the linear speed requirement into a rotational speed requirement.

[0075] Next, the system obtains the motor's reduction ratio and, combined with the calculated drum speed, calculates the precise speed and corresponding operating frequency required for the motor to achieve the target drum speed through transmission ratio conversion. This conversion process ensures that the motor output matches the actual needs of the unwinding mechanism.

[0076] Ultimately, based on these precisely calculated required motor speeds and frequencies, the system commands and controls the motor to operate according to these parameters, thereby achieving precise and stable control of the unwinding process of the unwinding machine and effectively avoiding linear speed fluctuations and control instability caused by parameter mismatches in traditional solutions.

[0077] During the aforementioned process, as the unwinding machine continuously unwinds, information such as the drum diameter, remaining layers, and number of turns will constantly change. If the control system relies solely on initially calculated parameters without a real-time update mechanism, the motor control parameters will mismatch with the actual drum state, leading to fluctuations in the unwinding linear speed and uncontrolled tension, potentially causing the strapping to break or stack. Furthermore, due to changes in the unwinding diameter, if the required motor frequency cannot be automatically adjusted according to the real-time drum diameter, it may result in insufficient torque at low speeds or overspeed alarms at high speeds, causing the equipment to stop abruptly and affecting production efficiency and stability.

[0078] The low-speed range refers to the initial unwinding stage when the roll diameter is still large, the drum speed is very low (motor speed is also low), but the required tension (pull force) of the strapping is very high. At this time, the motor must output a sufficiently large torque to maintain constant tension; otherwise, the phenomenon of "not being able to pull" or "slipping" will occur, which is called insufficient torque in the low-speed range.

[0079] The high-speed section refers to the period near the end of unwinding when the roll diameter decreases, requiring the drum to rotate at high speed to maintain a constant linear velocity (the motor speed is also very high at this time). If the motor frequency cannot automatically correct itself as the roll diameter decreases, the motor may overspeed, triggering an "overspeed alarm," or it may result in insufficient output torque, causing tension loss or tape breakage, which is called insufficient torque or overspeed alarm in the high-speed section.

[0080] Therefore, in order to solve this problem, the method further includes the following steps:

[0081] S6: During the unwinding process of the unwinding machine, the reading of the photoelectric detection counter is acquired in real time;

[0082] S7: Calculate the real-time update information of the drum based on the readings and drum information;

[0083] S8: Calculates the real-time updated rotational speed of the drum based on real-time updated information and unwinding line speed;

[0084] S9: Calculate the required speed and frequency for real-time motor updates based on the motor reduction ratio and the real-time update speed of the drum;

[0085] S10: Control the motor operation according to the required speed and frequency of the motor in real time, thereby controlling the unwinding machine to unwind.

[0086] The reading of the photoelectric detection counter reflects the number of unwinding turns of the drum.

[0087] Real-time update information of the drum refers to the drum status data obtained during the unwinding process based on the actual unwinding amount. This can be achieved using parameters such as real-time diameter, number of remaining turns, number of remaining layers, and real-time tape exit height.

[0088] In one embodiment, the method can be implemented as follows: During the unwinding process of the unwinding machine, a photoelectric detection counter can be installed on the path of the packing strap. For example, whenever the packing strap passes a point, the counter generates a pulse signal. The PLC control system reads the pulse reading of the counter in real time, which represents the number of wraps of packing strap unwound.

[0089] Based on the real-time readings and the initial drum information acquired during system startup (e.g., initial drum diameter, strapping thickness), the PLC control system can calculate the real-time update information of the drum. Once the real-time update information of the drum, such as the real-time diameter, is obtained, the PLC control system will recalculate the real-time update rotational speed of the drum, taking into account a preset unwinding speed (e.g., maintaining a speed of 20 meters per minute). For example, the real-time rotational speed of the drum can be obtained by dividing the unwinding speed by the real-time drum circumference (π * real-time drum diameter). Then, based on the real-time drum rotational speed and the known motor reduction ratio, the PLC control system can calculate the required real-time update rotational speed of the motor. For example, if the motor reduction ratio is 1:10 and the real-time drum rotational speed is 10 RPM, then the required motor speed is 100 RPM.

[0090] Based on this, the PLC control system calculates the required frequency for the motor's real-time updates, taking into account parameters such as the number of pole pairs. Finally, the PLC sends these updated motor speed and frequency commands to the motor. Upon receiving the commands, the motor adjusts its output to control the unwinding machine, ensuring the strapping is released at the set linear speed, maintaining control even if the drum diameter changes during unwinding.

[0091] By introducing a mechanism that acquires real-time readings from a photoelectric detection counter, calculates real-time updated information about the roll, and dynamically adjusts motor operating parameters accordingly, this application solves the control accuracy problem caused by continuous changes in the roll diameter during the unwinding of ultra-large rolls. This solution maintains the unwinding linear speed and controls the tension of the strapping, preventing the strapping from breaking or piling up. Simultaneously, because the required motor frequency can be automatically corrected based on the real-time roll diameter, it solves the problems of insufficient torque at low speeds and overspeed alarms at high speeds, reducing the occurrence of sudden equipment stops and improving production continuity and stability.

[0092] Furthermore, the drum information includes at least the drum diameter; step S3 includes:

[0093] S31: Calculate the circumference of the drum based on the drum diameter;

[0094] S32: The drum rotation speed is calculated based on the drum circumference and unwinding linear speed.

[0095] The formula for calculating the circumference of the roll is: Circumference of the roll = π * diameter of the roll.

[0096] The formula for calculating drum speed is: Drum speed = Unwinding linear speed / Drum circumference.

[0097] This method, by explicitly including the drum diameter in the drum information, provides a clear input for subsequent accurate calculations, avoiding calculation errors caused by incomplete or unclear drum information. Based on this, the calculation of the drum speed is refined into two sub-steps. First, based on the obtained drum diameter, the drum circumference can be accurately calculated. This step is crucial in connecting the drum diameter and linear velocity, laying a precise foundation for subsequent speed calculations. Second, after obtaining the accurate drum circumference, combined with the real-time unwinding linear velocity, the actual current drum speed can be accurately deduced based on the physical relationship between linear velocity, circumference, and speed. It is precisely this calculation method based on real-time drum diameter and unwinding linear velocity that makes the calculated drum speed closer to the actual operating state, avoiding the errors caused by using fixed drum diameters or table lookups in traditional methods.

[0098] Furthermore, the motor drives the unwinding machine through a gear assembly, which includes a small gear connected to the motor and a large gear meshing with the small gear; step S4 includes:

[0099] S41: Obtain the motor reduction ratio, the number of the first gear of the large gear, and the number of the second gear of the small gear;

[0100] S42: Calculate the required motor speed based on the number of the first gear, the number of the second gear, the motor reduction ratio, and the drum speed;

[0101] S43: Calculate the required frequency of the motor based on the required speed of the motor.

[0102] Among them, the gear component refers to a mechanical transmission device used to transmit power and change the direction or speed of motion, including a small gear connected to the motor, which is the driving gear, and a large gear connected to the turntable, which is the driven gear. The small gear and the large gear mesh to transmit power.

[0103] The formula for calculating the required motor speed is: Required motor speed = Drum speed * (Number of first gears / Number of second gears) * Motor reduction ratio. This formula is based on the classic mechanical transmission law that "speed is inversely proportional to the number of teeth and directly proportional to the reduction ratio," and is derived step-by-step in three stages:

[0104] First layer: The speed ratio relationship between the large and small gears.

[0105] Assume the pinion (driving gear) has Z2 teeth and the gear (driven gear) has Z1 teeth. For an external gear pair, the rotational speeds of the two gears are inversely proportional to the number of teeth: n2 / n1 = Z1 / Z2. Here, n2 is the rotational speed of the pinion, and n1 is the rotational speed of the gear. Therefore, the rotational speed of the pinion is n2 = n1 * (Z1 / Z2).

[0106] Second layer: Introduce the motor reduction ratio i.

[0107] The motor output shaft first passes through a reducer (speed ratio i) and then drives a pinion. The relationship between the required motor speed n and the reducer output shaft (i.e., pinion) speed n2 is: n2 = n / i. Substituting into the above formula for calculating the pinion speed, we get: n / i = n1*(Z1 / Z2); thus, we can derive the required motor speed: n = n1*(Z1 / Z2)*i.

[0108] Third layer: Introduce the drum rotation speed nr.

[0109] In this device, the large gear is coaxial with the turntable (drum), so the drum speed nr is the same as the large gear speed n1. Therefore, the required motor speed is: n = nr * (Z1 / Z2) * i, which means the required motor speed = drum speed * (number of first gears / number of second gears) * motor reduction ratio.

[0110] Once the required motor speed is precisely calculated, the PLC control system can convert the required speed into the corresponding required frequency based on the motor type and its electrical characteristics. Specifically, the formula for calculating the required motor frequency is: Required motor frequency = (Required motor speed / Standard speed 1450 rpm) * 50Hz.

[0111] This application significantly improves the accuracy of calculations by incorporating detailed parameter considerations of the gear components in the specific mechanical transmission structure between the motor and the unwinding machine when calculating the required motor speed and frequency. This precise calculation ensures a high degree of match between the motor's output speed and frequency and the actual required speed of the unwinding machine, thereby achieving precise control of the unwinding machine. Therefore, this application effectively solves the control accuracy problem caused by insufficient consideration of transmission details in traditional solutions, avoiding operational instability phenomena such as insufficient torque at low speeds and overspeed alarms at high speeds, and significantly improving the stability and production efficiency of the unwinding process.

[0112] Furthermore, step S6 includes:

[0113] S61: During the unwinding process of the unwinder, obtain the first exit height of the strapping at the initial exit moment, and determine whether the first exit height has reached the near end face;

[0114] S62: If the motor reaches the near end face, an end face warning message will be issued and the user will be reminded to reduce the motor speed.

[0115] S63: Determine if there is an abnormality in the unwinding at the end face. If an abnormality occurs, control the unwinding machine to stop running. If no abnormality occurs, control the motor to run according to the reduced motor speed.

[0116] S64: If the near end face is not reached, obtain the reading of the photoelectric detection counter.

[0117] In this context, "near-end face" refers to the top and bottom ends of the roll. The near-end face specifically refers to the critical state or area where the packing strap is about to completely detach from the roll in the vertical direction during unwinding. This is typically defined by a preset threshold for the packing strap's exit height. End-face warning information refers to the alert message issued by the system to the user when it determines that the packing strap has reached the near-end face. This can be achieved through methods such as audible and visual alarms, screen displays, or communication signal transmission.

[0118] Whether the unwinding at the end face is abnormal refers to the real-time monitoring and judgment of the unwinding status of the packing strap when it is unwound to the near end face stage, and whether the packing strap has abnormalities such as side roll-up, positional deviation, or loosening at the near end face.

[0119] This solution effectively addresses potential safety and stability issues at the end of unwinding large rolls by predicting and handling the condition of the packing tape near the end face during unwinding, ensuring a smooth transition and continuity in the unwinding process. Specifically, during unwinding machine operation, the initial exit height of the packing tape at the moment of exit is obtained to determine whether the packing tape has reached the near-end face. This predictive mechanism is the core of the entire solution, compensating for the lack of early warning for the end face of the roll in existing technologies. Once it is determined that the near-end face has been reached, the system immediately issues a warning message and reminds the user to reduce the motor speed. This provides operators with an opportunity for timely intervention and effectively reduces the risk of end unwinding through deceleration.

[0120] Subsequently, the system continuously monitors the unwinding process for any abnormalities. If an abnormality is detected, the unwinding machine is immediately stopped, providing a high level of safety to effectively prevent equipment damage or personnel injury. If no abnormality is detected, the motor continues to operate based on the reduced speed, ensuring a smooth transition. While the strapping tape is still close to the end face, the system continues to perform the routine operation of acquiring photoelectric detection counter readings, ensuring continuous data acquisition and precise control during the normal unwinding phase.

[0121] In this way, this solution adds refined management of the unwinding end to the existing real-time acquisition of photoelectric detection counter readings. This ensures that the entire unwinding process not only maintains high-precision control during normal stages but also provides necessary safety guarantees and smooth transition mechanisms during the critical end stages. Combined with the overall control logic of the previous solution, which updates drum information and adjusts motor operation in real time using photoelectric detection counter readings, this results in higher safety, stability, and continuity for the entire ultra-large roll unwinding control system throughout its entire lifecycle, avoiding sudden failures and production interruptions caused by the drum approaching the end.

[0122] Furthermore, the roll information also includes roll height, strapping width, and strapping thickness; step S7 includes:

[0123] S71: Calculate the number of the first turns of each layer of the strapping on the roll before unwinding, based on the roll height and strapping width.

[0124] S72: Based on the number of the first wraps and the reading, calculate in real time the number of the second wraps remaining in each layer of the packing tape during the unwinding process;

[0125] S73: Calculate the number of the first layer of the packing strap on the drum before unwinding based on the drum diameter and packing strap thickness in the drum information, and calculate the number of the second layer of the packing strap remaining during unwinding in real time based on the number of the first layer, the number of the first turns, and the reading.

[0126] S74: Based on the drum diameter, number of first turns, reading, and strapping thickness before unwinding, calculate the remaining second drum diameter during the unwinding process in real time;

[0127] The real-time updated information includes at least the number of the second loop, the number of the second layer, and the diameter of the second roll.

[0128] The formula for calculating the first number of turns is: First number of turns = Roll height / Strap width. That is, by dividing the total height of the strapping on the roll by the width of the strapping, you can get the total number of the first turns of the strapping wrapped around the roll.

[0129] The second number of turns indicates the number of turns remaining in each layer during the unwinding process. The reading of the photoelectric detection counter indicates the number of turns that have been unwound. The first number of turns is the total number of turns in each layer. The remaining number of turns in each layer is obtained by subtracting the number of turns that have been unwound from the total number of turns. That is: the second number of turns = the first number of turns - the reading.

[0130] The total number of the first layers of strapping wrapped on the roll can be obtained by subtracting the diameter of the roll core from the roll diameter, dividing by the thickness of the strapping, and then dividing by 2.

[0131] After obtaining the first layer number, the remaining layer number can be obtained by subtracting the ratio of the number of rolls already unwound to the total number of rolls per layer. The remaining layer number is the second layer number. When the ratio of the number of rolls already unwound to the total number of rolls per layer (reading / first roll number) is less than 1, subtract the decimal less than 1 from the first layer number. The integer part is equivalent to subtracting one. Assuming the first layer number is 10, subtracting the decimal less than 1 from 10 gives an integer part of 9. This means that the currently unwound layer is the 10th layer on the outermost side of the roll, leaving 9 layers (the second layer number).

[0132] When the ratio of the reading to the number of the first roll is an integer or decimal greater than 1, the principle for calculating the remaining number of the second roll is the same as described above. For example, when the ratio of the reading to the number of the first roll is 1.1, 10 - 1.1 = 8.9, the integer part of which is 8, the remaining number of the second roll is 8, and the current roll number is the 9th roll.

[0133] Multiplying the ratio of the reading to the number of first turns by the thickness of the packing strap gives the total thickness of the unwound packing strap. Then, by subtracting the total thickness of the unwound packing strap from the diameter of the roll before unwinding, the remaining diameter of the second roll during the unwinding process can be calculated in real time. Therefore, the formula for calculating the diameter of the second roll is: Second roll diameter = Roll diameter - (Reading / Number of first turns) * Packing strap thickness.

[0134] Through the aforementioned series of precise calculations, this method can generate real-time updated information, including the number of second turns, the number of second layers, and the second drum diameter. This information, as a comprehensive and accurate description of the unwinding state of the large roll, is input into subsequent control logic. For example, when calculating the real-time updated drum speed, the system utilizes this precise real-time updated information instead of relying on rough estimates. Subsequently, based on the motor reduction ratio and the real-time updated drum speed, the system can calculate the required speed and frequency for the motor's real-time update, and precisely control the motor operation accordingly, thereby achieving refined, closed-loop control of the unwinding process. This interconnected precise calculation and real-time feedback mechanism allows the system to continuously adapt to dynamic changes in the drum diameter, ensuring the stability of the unwinding linear speed and the accuracy of tension control, effectively avoiding linear speed fluctuations and tension loss of control caused by inaccurate roll diameter estimation.

[0135] The above method allows for dynamic adjustment of unwinding parameters based on changes in the radial dimension of the roll, thereby improving unwinding stability and accuracy. However, in its implementation, for vertically mounted extra-large rolls, the real-time exit position information of the strapping in the vertical direction is not effectively acquired and incorporated into the real-time update mechanism. This deficiency prevents the control system from grasping the actual unwinding state of the strapping, potentially leading to inaccurate vertical position control of the strapping during unwinding. This can result in problems such as strapping stacking, deviation, or tension fluctuations, affecting the stability and accuracy of unwinding extra-large rolls.

[0136] Therefore, in order to solve this problem, step S7 further includes:

[0137] S75: Obtain the exit direction of the packing tape during the unwinding process, including exiting from top to bottom and exiting from bottom to top;

[0138] S76: When the tape exits from top to bottom, the real-time tape exit height is calculated by subtracting the product of the reading and the tape width from the first tape exit height.

[0139] S77: When the tape exits from bottom to top, the real-time tape exit height is calculated by adding the first tape exit height to the product of the reading and the tape width.

[0140] The real-time update information also includes the real-time conveyor belt height.

[0141] This application's solution, based on real-time updates of the drum's radial information, further introduces real-time monitoring and updating of the vertical position of the strapping. Specifically, during the operation of the unwinding machine, the system first obtains the exit direction of the strapping, ensuring consistency between the calculation logic and the actual physical movement direction.

[0142] When the system determines that the strapping is exiting from top to bottom, the exit point of the strapping will gradually decrease as unwinding progresses. At this point, the system will subtract the product of the accumulated reading of the photoelectric detection counter and the strapping width from the initial exit height. The product of the photoelectric detection counter reading and the strapping width accurately quantifies the distance the strapping has been unwound in the vertical direction. By subtracting this distance from the initial height, the current real-time exit height of the strapping can be accurately obtained.

[0143] Conversely, when the strapping emerges from bottom to top, the exit point of the strapping gradually rises as unwinding progresses. In this case, the system calculates the first exit height by adding the product of the accumulated reading from the photoelectric detection counter and the strapping width. This product represents the distance the strapping has been unwound vertically; by adding it to the initial height, the current real-time exit height of the strapping can be accurately obtained.

[0144] Through the above method, regardless of whether the strapping is unwound upwards or downwards, the system can accurately and in real-time obtain the vertical exit position of the strapping. This real-time exit height, along with previously acquired and updated radial information of the drum (such as the number of turns, layers, and diameter), is incorporated into the real-time update information, enabling the PLC control system to obtain comprehensive three-dimensional information about the strapping's unwinding status. This comprehensive real-time feedback allows the PLC control system to adjust unwinding parameters not only based on changes in the drum's radial dimensions but also to make precise adjustments based on changes in the strapping's vertical position. For example, when the real-time exit height deviates from the preset range, the PLC can issue commands to adjust the unwinding machine's vertical guide mechanism or tension control, effectively preventing problems such as strapping stacking, deviation, or tension fluctuations during unwinding. This comprehensive real-time updating and control of radial and vertical information improves the stability and accuracy of large-roll unwinding, ensuring the smooth and orderly exit of the strapping.

[0145] Please refer to Figure 3 This application provides a PLC control device for unwinding ultra-large rolls, used to implement any of the methods, the device comprising:

[0146] Judgment module 201: After the start button of the unwinding machine is pressed, determine whether the unwinding position of the drum on the unwinding machine is abnormal;

[0147] Start-up module 202: If there is no abnormality in the unwinding position of the roll, start the unwinding machine and obtain the roll information of the strapping and the unwinding linear speed of the strapping.

[0148] First calculation module 203: Calculates the drum rotation speed based on the drum information and the unwinding linear speed;

[0149] Second calculation module 204: Obtain the motor reduction ratio, and calculate the required motor speed and frequency in combination with the drum speed;

[0150] Control module 205: Controls the operation of the motor according to the required speed and frequency of the motor, thereby controlling the unwinding of the unwinding machine.

[0151] The judgment module 201 refers to the unit used to perform logical judgment functions, which can be implemented using a specific program segment in a programmable logic controller (PLC), a microcontroller (MCU), or a logic circuit in an application-specific integrated circuit (ASIC).

[0152] The startup module 202 is a unit used to initialize the operation of the equipment and acquire initial data. It can be implemented by using the output control relay or contactor of the PLC and combined with the sensor data acquisition interface.

[0153] The first calculation module 203 refers to the unit used to perform initial data calculations, which can be accomplished using the PLC's arithmetic operation instruction set, digital signal processor (DSP), or general-purpose processor (CPU).

[0154] The second calculation module 204 refers to a unit used to perform further data calculations, which can be accomplished using similar computing hardware as the first calculation module, such as the arithmetic unit of a PLC or an embedded processor.

[0155] The control module 205 refers to the unit used to output control signals based on the calculation results to drive the actuator. It can be implemented using the analog output module, pulse output module of the PLC, or the drive interface of the frequency converter.

[0156] The overall operational logic of this solution lies in decomposing the complex control method for unwinding ultra-large rolls into a series of collaborative functional modules, thereby achieving an automated, precise, and stable unwinding process. Specifically, when the unwinding machine's start button is pressed, the judgment module 201 intervenes first. Its core function is to act as the first checkpoint for safety and correctness. By initially judging the unwinding position of the packing tape, it promptly detects and avoids potential anomalies, laying a safe foundation for subsequent precise control.

[0157] Once it is confirmed that there is no abnormality in the unwinding position, the start module 202 is activated. It is not only responsible for starting the physical operation of the unwinding machine, but more importantly, it synchronously acquires the initial roll information of the packing tape and the preset unwinding linear speed. These data are the cornerstone for the entire control system to perform accurate calculations.

[0158] Subsequently, the first calculation module 203 receives this basic data and, based on the drum information and unwinding linear speed, accurately calculates the required rotational speed of the drum. This is a crucial step in achieving constant linear speed unwinding, ensuring that the linear speed remains stable even when the drum diameter changes continuously. Next, the second calculation module 204, based on the motor reduction ratio and combined with the drum rotational speed output by the first calculation module 203, further converts the mechanical motion requirements into electrical parameters that the motor can recognize and execute—namely, the required motor speed and frequency—thereby ensuring that the motor can accurately respond to the drum's rotational speed demands.

[0159] Ultimately, the control module 205, as the core of the entire system, precisely drives the motor based on the required speed and frequency provided by the second calculation module, thereby achieving stable, continuous, and precise unwinding of the unwinder. It is through this modular device design that this solution can systematically carry out and execute the complex calculations and real-time adjustments proposed in previous methods. The close cooperation between the judgment module 201, the start-up module 202, the first calculation module 203, the second calculation module 204, and the control module 205 automates and refines the initial judgment, data acquisition, multi-level calculations, and final motor drive in the method. For example, the steps of acquiring photoelectric detector counter readings in real time, calculating real-time roll update information, and dynamically adjusting motor speed and frequency based on this information can all be efficiently achieved through the collaborative work of these functional modules. This combination of device and method ensures that problems such as linear speed fluctuations and tension loss of control can be effectively suppressed during the unwinding of ultra-large rolls, significantly reducing the risk of strip breakage or stacking, and greatly reducing the frequency of equipment emergency stops, thereby significantly improving production continuity and efficiency.

[0160] Please refer to Figure 4 , Figure 4 This application provides a schematic diagram of the structure of an electronic device 3, comprising: a processor 301 and a memory 302. The processor 301 and the memory 302 are interconnected and communicate with each other through a communication bus 303 and / or other forms of connection mechanism (not shown). The memory 302 stores computer-readable instructions executable by the processor 301. When the electronic device is running, the processor 301 executes the computer-readable instructions to perform the method in any optional implementation of the above embodiments to achieve the following functions: after the start button of the unwinding machine is pressed, it is determined whether the unwinding position of the roll on the unwinding machine is abnormal; if the unwinding position of the roll is not abnormal, the unwinding machine is started and the roll information of the packing tape and the unwinding linear speed of the packing tape are obtained; the roll speed is calculated based on the roll information and the unwinding linear speed; the motor reduction ratio is obtained, and the required motor speed and the required motor frequency are calculated in combination with the roll speed; the motor is controlled to run according to the required motor speed and the required motor frequency, thereby controlling the unwinding of the unwinding machine.

[0161] This application provides a computer-readable storage medium storing a computer program thereon. When the computer program is executed by a processor, it performs the method in any optional implementation of the above embodiments to achieve the following functions: after the start button of the unwinding machine is pressed, it determines whether the unwinding position of the roll on the unwinding machine is abnormal; if the unwinding position of the roll is not abnormal, it starts the unwinding machine and obtains the roll information of the packing tape and the unwinding linear speed of the packing tape; it calculates the roll speed based on the roll information and the unwinding linear speed; it obtains the motor reduction ratio and calculates the required motor speed and the required motor frequency based on the roll speed; it controls the motor operation based on the required motor speed and the required motor frequency, thereby controlling the unwinding machine to unwind.

[0162] The computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.

[0163] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings or direct couplings or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0164] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0165] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0166] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0167] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A PLC control method for unwinding an ultra-large roll, characterized in that, The method includes the following steps: S1: After starting the unwinding machine, check if the unwinding position of the drum on the unwinding machine is abnormal; S2: If there is no abnormality in the unwinding position of the roll, start the unwinding machine and obtain the roll information of the strapping and the unwinding linear speed of the strapping; the roll information includes at least the roll diameter, roll height, strapping width and strapping thickness. S3: Calculate the drum rotation speed based on the drum information and the unwinding linear speed; S4: Obtain the motor reduction ratio, and calculate the required motor speed and frequency based on the drum speed; S5: Control the operation of the motor according to the required speed and frequency of the motor, thereby controlling the unwinding machine to unwind; S6: During the unwinding process of the unwinding machine, the reading of the photoelectric detection counter is acquired in real time; S7: Calculate the real-time update information of the drum based on the readings and the drum information; the real-time update information includes the real-time diameter, remaining number of turns, remaining number of layers, and real-time exit height; S8: Calculate the real-time updated rotational speed of the drum based on the real-time update information and the unwinding linear speed; S9: Calculate the required speed and frequency for real-time motor updates based on the motor reduction ratio and the real-time updated speed of the drum; S10: Control the operation of the motor according to the required speed and frequency of the motor in real time, thereby controlling the unwinding machine to unwind; Step S6 includes: S61: During the unwinding process of the unwinding machine, the first exit height of the packing tape at the initial exit moment is obtained, and it is determined whether the first exit height has reached the near end face; S62: If the motor reaches the near end face, an end face warning message will be issued and the user will be reminded to reduce the motor speed. S63: Determine if the end face unwinding is abnormal. If an abnormality occurs, control the unwinding machine to stop running. If no abnormality occurs, control the motor to run according to the reduced motor speed. S64: If the near end face is not reached, obtain the reading of the photoelectric detection counter.

2. The PLC control method for unwinding an ultra-large roll according to claim 1, characterized in that, Step S3 includes: S31: Calculate the circumference of the drum based on the diameter of the drum; S32: The drum rotation speed is calculated based on the drum circumference and the unwinding linear speed.

3. The PLC control method for unwinding an ultra-large roll according to claim 2, characterized in that, The motor drives the unwinding machine through a gear assembly, the gear assembly including a small gear connected to the motor and a large gear meshing with the small gear; step S4 includes: S41: Obtain the motor reduction ratio and the number of the first gears of the large gear and the number of the second gears of the small gear; S42: Calculate the required motor speed based on the number of the first gear, the number of the second gear, the motor reduction ratio, and the drum speed; S43: Calculate the required frequency of the motor based on the required speed of the motor.

4. The PLC control method for unwinding an ultra-large roll according to claim 1, characterized in that, Step S7 includes: S71: Calculate the number of the first turns of each layer of the packing strap on the roll before unwinding, based on the roll height and the packing strap width; S72: Based on the first number of turns and the reading, calculate in real time the number of the second turns remaining in each layer of the packing tape during the unwinding process; S73: Calculate the first layer number of packing straps on the roll before unwinding based on the roll diameter and the packing strap thickness in the roll information, and calculate the second layer number of packing straps remaining during unwinding in real time based on the first layer number, the first number of turns and the reading. S74: Calculate the remaining second diameter of the drum during unwinding based on the drum diameter before unwinding, the first number of turns, the reading, and the thickness of the packing strap.

5. The PLC control method for unwinding an ultra-large roll according to claim 4, characterized in that, Step S7 also includes: S75: Obtain the exit direction of the packing tape during the unwinding process, wherein the exit direction includes exiting the tape from top to bottom and exiting the tape from bottom to top; S76: When the tape exit direction is from top to bottom, the real-time tape exit height is calculated by subtracting the product of the reading and the width of the packing tape from the first tape exit height; S77: When the tape exit direction is from bottom to top, the real-time tape exit height is calculated by adding the first tape exit height to the product of the reading and the width of the packing tape.

6. A PLC control device for unwinding an ultra-large roll, characterized in that, The apparatus for implementing the method according to any one of claims 1-5, the apparatus comprising: Judgment module: After the start button of the unwinding machine is pressed, determine whether the unwinding position of the drum on the unwinding machine is abnormal; Start-up module: If there is no abnormality in the unwinding position of the roll, start the unwinding machine and obtain the roll information of the strapping and the unwinding linear speed of the strapping; First calculation module: Calculates the drum rotation speed based on the drum information and the unwinding linear speed; The second calculation module obtains the motor reduction ratio and calculates the required motor speed and frequency based on the drum speed. Control module: Controls the operation of the motor according to the required speed and frequency of the motor, thereby controlling the unwinding machine to unwind.

7. An electronic device, characterized in that, It includes a processor and a memory, the memory storing computer-readable instructions that, when executed by the processor, perform the steps of the method as described in any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it performs the steps of the method as described in any one of claims 1-5.

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