First of all, the precision coater uses two rollers to tighten the tension division at the nozzle, and the tension is controlled by two tension controllers respectively (the control method is PID control). Take the float roller position as input.

First, the fundamentals

First of all, set the tension size and determine the position of the floating roller (the vertical direction of the floating roller gravity and the vertical component of the tension size balance). If the tension is small, the float roller position is reduced, the plc signal is given, and the current of the winding motor is increased (taking the second half of the precision coater as an example), so that the winding torque is increased and the tension is increased. And vice versa.

Let's talk about a precision coater
With the increase of winding, the tension will be reduced (the radius will be larger) under the same torque of the motor. Therefore, according to the winding length, the plc will reduce the tension you set as the winding length increases.