Winder control

I want to control the machine like this picture.

The machine isn't isolate the tension between Rewind and Unwind. And can change Unwind and Rewind roll, Maxspeed 250m/m
I decide to control the unwind motor with Torque mode and Rewind motor in speed mode. And I use PLC to calculate Diameter and control 2 VFD.
The Dancer is used to control the Rewind motor

Somebody have another method to control this machine.Help me plz.


Any help would be great.

Thanks ahead of time

My approach would be:

Run both in Speed Mode.

Choose one winder to be the master. It will run at whatever line speed you wish to run at.

The other winder will follow at the same speed as the master, but will trim it's speed as needed to keep the dancer in the middle position.

You will need diameter sensors or diameter calculators to know how fast to run the motor to achieve the desired material speed. To create a diameter calculator, you may need to add an encoder to one of the idler rolls so you know the actual web speed.

Do a search of this forum and you will find other applications just like yours.

Thanks kekrahulik,
I have 2 solution:
2 Drive will run in speed mode.
1 Drive run Torque and 1 Drive run Speed.
I don't know what solution is good in high speed (250m/m).
And want to Calculate Diameter what equation is good:
v=w.r
v:line speed
w:reel speed
r:radius
R = R_core + Thickness_web*N
N: round/sample_time

or you have any idea or suggest? Thanks you


http://www.plctalk.net/qanda/member.php?u=55789

See attached file.

Bumbum1291:

This little file may help you.

widelto said:

Bumbum1291:

This little file may help you.

Click to expand...

Onstege said:

http://download.sew-eurodrive.com/download/pdf/11341114.pdf

Click to expand...

el greco said:

http://www.motrona.com/winding.html

Click to expand...

Thanks all . It very helpful.

I would as you said use set the unwind VFD to torque control with the speed set point set to 0 use the dancer position for torque command and set the winder BFD to speed control. but you will need some kind of speed feedback. using the PLC to set the speed will be very challenging to say the least why not use an ultrasonic measuring sensor to measure the diameter of both rolls. that way you can have the PLC slowdown and stop when the unwind roll is empty. and can have a constant web speed.
or use a tack / encoder feedback from the dancer roll speed to regulate the web speed.
keep in mind that the winder speed will start out at a high motor speed and slow down as the roll builds up. and of course the unwind motor will start out at a low speed and end up at a high speed. that is if you want to keep the line speed constant.
also to do what you want both the winder and the unwinder VFD's must have a braking resistor to dump the energy when they are in torque mode. (the energy has to go somewhere )
you may want to consider a common buss configuration
also think about how you are going to handle a broken web or an emergency stop
the unwinder has to stay on until the rolls are at zero speed otherwise on a large heavy roll it could take a long time to coast to a stop.