Hi all, I have to program a machine with an unwinder and a winder. Currently I have 3 VFD Powerflex 527. I need your experience about this topic. Currently I am having trouble with the unwinder because I do not have a sensor to read the diameter of the roll so I do not know how can I program the close loop to increase the speed in accordance to the diameter of the roll. As you know when the material's roll is full the unwinder goes slow and when the roll becomes to a core measure the speed becomes faster. The linear speed to feed the material has to be constant in meter per minute. Do someone has an idea about how can I fixed? Best Regards