Rockwell Automation 9329 Drive Application Software Tension Control Gen. Units - Manual (Page 14)

FM – Tension Control
Drive Application Software – page 14 of 52
user, commissioning engineer, and may require additional maintenance. Therefore,
we recommend application of these modes of tension regulation for only the most
experience engineers.
4.2.2.1 Dancer Position Control with Torque Trim
This mode of dancer position control requires accurate tension set point
information from the mechanical loading system. The method of loading and the
mechanical construction of the dancer direct effect the amount of tension applied
to the web. Without accurate web tension information from the loading device,
this mode of tension regulation will not function.
4.2.2.2 Dancer Position Control with Speed Trim & Torque Feed Forward
In this mode of tension control the tension (force) applied to the web is dependant
on the mechanical load applied to the dancer. The tension applied to the web is
independent of the regulating sections speed or torque as long as the mechanical
dancer has not reach it’s minimum or maximum travel limits. The controlling
section varies it’s speed to maintain the dancers position at typically 50% total
travel. The position feedback of the dancer is required by the controlling section.
In this mode of dancer position control, the required torque for tension is
calculated from the mechanical loading information and fed forward to the drive.
This requires accurate tension set point information from the mechanical loading
system. The method of loading and the mechanical construction of the dancer
direct effect the amount of tension applied to the web. Without accurate web
tension information from the loading device, this mode of tension regulation will
not function.
4.2.2.3 Tension Feedback with Torque Trim (for Inline Tensioning)
When applying this mode of tension regulation on an inline section, additional
information is required regarding the tension on the web of the adjacent section.
The dynamic information required from the adjacent sections tension makes this
mode more complicated to implement and is there for not recommended for retro
fits and systems with limited engineering resources. See section 3.4
4.2.2.4 Tension Feedback with Speed Trim & Torque Feed Forward
In this mode of tension regulation, the actual web tension is measured by a force
measurement device (load cell / transducer). The controlling section requires a
set point of web tension and the feedback of actual web tension. Based on the
values of these inputs the section will adjust (trim) it’s speed to maintain the
feedback tension equal to the set point tension. In addition, the torque required
due to tension is feed forward to the drive. In this configuration the drives speed
regulator is only trying to maintain the tension, not also generate the total required
torque. This causes the speed regulator to typically operate around zero
independent of the total torque required.
4.2.2.5 Open Loop Torque Control (for Inline Tensioning)
When applying this mode of tension regulation on an inline section, additional
information is required regarding the tension on the web of the adjacent section.
The dynamic information required from the adjacent sections tension makes this
mode more complicated to implement and is there for not recommended for retro
fits and systems with limited engineering resources. See section 3.4
4.2.2.6 Open Loop Torque Control with Speed Trim
This mode of tension regulation trims the speed reference of the section based on
the torque tension set point and torque actual feedback. This type of control can
be beneficial for torque applications with webs of very high spring coefficients like
steel. This configuration requires the “master” section (speed regulated) adjacent
to the torque section be coordinated with the same speed reference. The tuning
for this mode is sometimes very difficult and should be left for only the most
experienced engineers. This is not a typical (conventional) form of torque control.