4 MM440 drives connected on profibus, torque question

Hey,


Another question about tension on carpet.

I have to change 4 DC-motors by 4 AC-motors (2,2kW). I ordered an S7-315-2DP CPU and 4 MM440 frequency drives. And an OP7. (and much more, but doesn't matter for this topic)

The first motor is Master. the 3 others have to run 10% faster.

Motor 1 2 and 3 have a tension setting on the Operating Panel (OP7). A tension for the carpet. It is needed for other applications that we do on the Carpet, not important for this topic.

The tension must be set from 0-100%

How should I create tension,

Torque control, or speed control with a torque limit ?


thanks

I would personally do it completely in speed control. If you put in any torque limit use that only as a machine/product protection. I think you can do better using straight speed-based tension control than you can with a speed/torque hybrid. As I remember this is a surface winder. So ruinning with a base speed reference based on the line speed reference plus a PI tension trim should do the trick.


Keith

hi

It's not the surface winder. Because that project was I succes, I had this project with 4 drives and torque control.

Your best choice for the follower drives is a combination of speed and torque control. As kamenges states above, a speed regulator with a torque trim would probably be the best arrangement--assuming the drives offer this mode of operation, of course.

Combo,

These drives offer speed with torque trim.
Another control (depending on your application) you might
want to look in to is - "droop".
The MM440's have this function too. This works well between two nip
points.
Look at the function diagrams.

ok

ok thanks