Introduction To Center Winder Controller; Mco 352 Center Winder Controller - Danfoss VLT Center Winder MCO 352 Operating Instructions Manual

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VLT

Center Winder MCO 352

3 Introduction to Center Winder Controller

3.1.1 MCO 352 Center Winder Controller

The MCO 352 Center Winder Controller uses the speed winder method with a diameter calculation and either a load cell or dancer feedback. Below is a

simplified block diagram of a tension controlled winder system. The system would be identical if a dancer were used except that the Taper Function block

would have a 0/4-20 mA output used to load the dancer air cylinder proportional to the tapered tension set point. The drive is fed an open loop speed

reference based on the calculated diameter of the roll. This signal is summed with a signal generated by a PID amplifier comparing the actual tension

feedback with a tapered tension set point. The tapered tension set point is actually the tension set point modified based on the roll diameter and the

taper set point. Taper generally reduces the tension set point hyperbolically with a change in diameter. The PID amplifier output is also reduced with

increasing diameter since the same change in reference will have a larger surface speed change as the roll increases in diameter. Ideally, the open loop

reference signal is scaled at core so that the surface speed of the core matches line speed. The diameter value is calculated by the ratio of line speed

verse winder speed.

(

)

Line speed

Roll diameter

core diameter

Winder speed

This calculation needs to be updated fairly quickly since the roll can change diameter very quickly when near the core. If the true diameter changes faster

than the diameter is calculated, the open loop reference speed will lag too far behind the required speed and the tension PID will need to make up too

much of the difference.

The Tension PID updates every 30 ms and should be updated at least 3 times faster than the diameter calculation. This is because the tension PID block

must be allowed to stabilize system tension before a new diameter is calculated, since the calculated diameter is used by both the open-loop reference

and as an input to the tension PID block.

MG.33.T1.02 - VLT

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