Introduction to tension control system:
In many industries of industrial production, winding control problems are often encountered. For example, in the production process of paper, textiles, plastic film, wire, printed matter, tape, metal strip wire, etc., the unwinding and winding tension of the strip material or wire is crucial to the quality of the product, so that constant tension control is required, that is, the product is subjected to the best tension in the winding process, and remains unchanged from beginning to end. If the tension is too large, it will cause the tensile deformation of the processed material; If the tension is too small, it will cause the stress deformation between the layers of the rolled material and the layers, resulting in irregular winding and affecting the processing quality. In the strip winding system, the tension control system plays an important role, and it is quite complicated.
A typical tension control system consists of a tension controller, a tension reader, a tension detector, a brake and a clutch. According to the loop can be divided into open loop, closed loop or free loop tension control system; According to the monitoring methods of different coils, it can be divided into ultrasonic, floating roller, tracking arm, etc. \

Tension control mode:
1. Manual control, constantly adjust the torque of the clutch or brake in the receiving, discharging or process, so as to obtain the required tension, which requires the user to check the tension of the controlled material at any time, adjust the output torque at any time, if the pneumatic brake or clutch is used, the manual controller can directly choose the precision pressure regulator, which can save the user a certain equipment cost. However, it is only suitable for some low-speed composite machines, extruders, textile machinery and other occasions where the tension control requirements are not high.
2. Semi-automatic method: using ultrasonic principle to automatically detect the diameter of the coil, so as to adjust the tension of the coil, such as: ARSENE LTC-838A calculation type ultrasonic tension controller, in essence, is a semi-closed loop control of tension, not only can automatically measure the warp, control the torque output, but also has the buffer start, anti-loose coil and inertia compensation functions. The implementation cost of this scheme is low, so it is widely used in mid-range machinery.
3. Automatic method: There are generally two detection methods. One is to measure the tension of the coil through the tension sensor, and then the controller automatically adjusts the clutch or brake to control the tension of the coil. This way is the full closed-loop control of tension, in principle, this scheme can reflect the change of tension in real time, so the control accuracy is the highest, so some high-grade finishing mill, high-speed slitter metallurgy using automatic tension control system.

Tension control system classification:
The tension control method can be divided into direct tension control method and indirect tension control method.
1. Direct tension control method: also known as feedback control, and can be divided into AB two kinds (A) The use of sensors such as tensiometers to detect the actual tension, the measured value as a feedback signal, forming a closed-loop tension system, that is, the actual value measured is compared with the given tension, and the deviation produces a control effect, so that the actual tension is equal to the given tension. Depending on the structure of the sensor, it can be divided into position type and feedback type control (B) The use of looper to establish tension, measure the looper amount, constitute a looper feedback control system, control the looper amount constant to make the product tension constant. The tension control method is suitable for high precision and high speed tension control, and has the advantages of high control precision and good real-time performance.
2. Indirect tension control: Also known as compensation control, it compensates for possible tension changes by adjusting parameters that affect tension stability, and indirectly maintains tension stability, that is, only the tension setting value is set, the actual value of tension is not collected by the detector, and the tension is not closed loop control, but the constant tension is indirectly controlled by controlling the current or excitation current of the controlled machine, that is, the driving motor. Thus, the motor torque remains unchanged to ensure that the tension of the rolled product is constant.

Expansion of tension control system:
The tension control system refers to the ability to control the tension of the raw material when it is transported on the equipment for a long time. Including machine acceleration, deceleration and uniform speed. Even in the case of an emergency stop, there should be the ability to ensure that the cut is not damaged. The stability of tension control is directly related to the quality of slitting products. If the tension is insufficient, the raw material will drift during operation, and the finished paper will wrinkle after slitting and rewinding. If the tension is too large, the raw material is easy to be broken, so that the broken end of the finished paper after slitting and rewinding will increase.