Abstract: Solving tension taper control requirements in the final winding stage of a heat setting machine is generally difficult. Danfoss' motion control card, with its high-precision control capabilities, combined with Danfoss' center winding program specifically developed for the winding industry, effectively addresses this issue. This article introduces the methods and experience of using Danfoss frequency converters and center winding cards to achieve center winding with tension taper control requirements.
Keywords: Danfoss frequency converter, tension taper, center winding
Abstract: It is difficult to control the winder of heat setting machine if the tapered tension control is needed. Danfoss's motion control card has high precision control ability, add the software developed by Danfoss specially for center winder, it can been used in these applications. The document will discuss the solution and experience of Danfoss center winder option card used in stress-relieving control.
Key words: Danfoss VLT Tapered-Tension Center-Winder
introduction:
The LSR800 heat setting machine, manufactured by the Dyeing and Printing Machinery Branch of Shanghai Pacific Textile Machinery Complete Equipment Co., Ltd., is suitable for high-grade fabrics undergoing stentering and ribbing treatment, reaching international advanced levels. Its winding control system, designed to meet the stringent tension taper control requirements of high-end foreign trade customers, utilizes a Danfoss FC302 series high-performance frequency converter and a center winding card, achieving excellent control performance and significant economic benefits.
I. Working principle of the LSR800 heat setting machine winding machine:
As shown in Figure 1, the LSR800 heat setting machine's winding unit has a cold water roller as its pre-stage, employing a Danfoss VLT AutomationDrive FC301 series driver for constant speed control. The motor is equipped with an encoder, which serves both as speed feedback for the cold water roller driver and as feedforward detection of the fabric linear speed for winding control. The winding drum has a diameter of 170 mm when empty and 1400 mm when full, a diameter variation of approximately 8 times. The winding drum uses a Danfoss Automation FC302 series high-performance driver with a center winding clamp. A tension detection roller is installed in the middle.
Figure 1. Structural diagram of the LSR800 heat setting machine winding machine
II. Functions of the Danfoss Center Wrap Card:
The interface terminals on the Danfoss center-wound card are shown in the figure on the right:
X55 is the encoder 2 input interface, which is used by default to connect the local encoder;
X56 is the encoder 1 input interface, which is used by default to connect a linear speed detection encoder;
X57 is a 10-port digital control signal input;
X58 uses a 24VDC power supply;
The X59 is an 8-port digital control signal output.
Figure 2. Outline of Danfoss Center Wrap Card
The most critical function of the Danfoss center winding card is roll diameter calculation. Generally, there are three methods for roll diameter detection: First, direct sensor measurement. This method is rarely used in practice because it requires on-site sensor installation, increasing costs and failure rates. Second, the thickness integration method, which is simple to control but lacks flexibility, requiring parameter adjustments when product types change. The third method is linear velocity calculation. According to the formula, since the linear velocity (D) is constant, the current diameter of the roll can be calculated by detecting the rotational speed of the linear velocity detection wheel and the rotational speed of the roll. This method offers high accuracy, and because linear velocity detection and roll speed detection are already integrated into the system, it is the most commonly used method in actual field operations.
With the roll diameter in mind, the tension taper setting can be determined based on the tension and taper settings. The tension taper setting curve of the Danfoss center winding card is shown in Figure 4. When the tension taper is set to 0, it indicates constant tension, and the tension setting is independent of the roll diameter. When the tension taper is set to 100%, it indicates constant torque, and the tension decreases by half for every doubling of the roll diameter.
III. Parameter settings and debugging of Danfoss center winding card:
First, perform open-loop debugging:
1. Set parameter 1924, "Linear velocity calibration coefficient".
First, do not load any fabric or thread; leave the drum empty. Then turn on the machine and set the linear speed to the maximum. While adjusting parameter 1924, observe the reading of the linear speed detection value on the LCP of the inverter operation panel until the reading equals 100,000. If the linear speed detection value is negative, it means that the main encoder is in the wrong direction, and the A and B phases of the main encoder should be swapped.
2. Set parameter 1925, "Speed Matching"
First, check if the "minimum winding diameter" setting of parameter 1905 is correct. The setting value of parameter 1905 should be equal to the minimum winding diameter. Then, reset the winding diameter to the minimum winding diameter and turn off the PID controller (set the gain and integral to 0). Then, turn on the machine and set the linear speed to the maximum value. At this time, the winding speed is completely determined by the linear speed feedforward. Then, while adjusting parameter 1925, observe the output linear speed of the winding until the output linear speed of the winding is the same as the actual value of the linear speed in the previous section.
3. Set parameter 1926, "Winding speed calibration coefficient".
Continue from step two, as the drum is now running at its highest speed. While adjusting parameter 1926, observe the reading of the winding speed detection value until it equals 100,000.
Then perform closed-loop debugging:
Load the fabric or thread onto the equipment as usual, set the linear speed to 0, and then start the machine. At this time, the PID controller should start working. Observe the output direction of the PID controller. If the actual tension is less than the set value, the drum should speed up (note that the situation is exactly the opposite when unwinding). Conversely, the drum should slow down, indicating that the direction of the PID controller is correct. If not, then set the PID output to reverse. Next, set the PID adjustment parameters to stabilize the drum speed. Then slowly increase the linear speed, optimizing the PID adjustment parameters while increasing the speed, until the whole machine is running at full speed and the system can operate stably.
IV. Operational Results:
Thanks to thorough preparation and the ease of use and powerful functionality of the MCT10 software provided by Danfoss, the system was successfully debugged on the first attempt at the user's site and has not encountered any faults since its startup.
References
[1] Danfoss MCO352 Center Winding Card Instruction Manual. MG.33.T1.02. Danfoss A/S
[2] Danfoss FC300 Inverter Programming Guide. MG.33.M3.41 Danfoss A/S
