I have R&D project that I am working on. It consist of an unwinder and a rewinder. The goal is to unwind the material from the unwinder and rewind the material at a specific tension and web speed on the rewinder. The material being wound is a strong plastic that can be stretched.
Web Width=30"
Core Dia.=3"
Max Roll Dia.=30"
Max Web Speed 650fpm
The hardware consist of siemens micromaster 440 drives that have encoder feedback. Each unwind/rewind motor has a load cell to measure tension. PLC is a S7-1200 series with an et200s rio
speed/speed trim signals to from drive are hardwired analog.
I have developed a few control systems that were rewinders only. Material was being fed to me from by another piece of equipment that was out of my scope. The control theory was calculated roll diameter and web speed sp. determined base speed and a dancer/load cell determined speed trim.
I am unsure how to go about controlling this process. What is standard practice? I would like to operate both drives to control speed but I feel since there is no dancer to increase or decrease the web length from rewind to unwind that the control would have to be so tight that it cannot be achieved.
I have never controlled a motor via "torque mode" and I am not sure how to go about it. It would seem to me that the motors must be sized very specifically to the process. I have a feeling they are not and are over sized quite a bit.
Luckily this is an R&D project so we can go about trying different practices.
Please see the attachment for a graphical view of the process.
Any help is greatly appreciated.
Web Width=30"
Core Dia.=3"
Max Roll Dia.=30"
Max Web Speed 650fpm
The hardware consist of siemens micromaster 440 drives that have encoder feedback. Each unwind/rewind motor has a load cell to measure tension. PLC is a S7-1200 series with an et200s rio
speed/speed trim signals to from drive are hardwired analog.
I have developed a few control systems that were rewinders only. Material was being fed to me from by another piece of equipment that was out of my scope. The control theory was calculated roll diameter and web speed sp. determined base speed and a dancer/load cell determined speed trim.
I am unsure how to go about controlling this process. What is standard practice? I would like to operate both drives to control speed but I feel since there is no dancer to increase or decrease the web length from rewind to unwind that the control would have to be so tight that it cannot be achieved.
I have never controlled a motor via "torque mode" and I am not sure how to go about it. It would seem to me that the motors must be sized very specifically to the process. I have a feeling they are not and are over sized quite a bit.
Luckily this is an R&D project so we can go about trying different practices.
Please see the attachment for a graphical view of the process.
Any help is greatly appreciated.
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