ABB ACS880 Firmware Manual page 35

In case the material breaks, normal operation is no longer possible or it can be dangerous to
proceed. The drive is able to detect such an occurrence with the web loss function.
Open loop tension control mode: In this mode the web loss is detected when the difference
between the actual line speed and the final speed reference added with overspeed reference
goes below the defined level.
Tension torque trim or Tension/Dancer speed trim mode: In this mode a material loss is
detected when the tension feedback from the web is less than the web loss limit set by the
user.
Select the required action for the web loss
condition:
• Disable - no action or function is disabled
• Alarm
• Fault
If available, select the source for the web
loss sensor feedback signal. Usually, it is a
digital signal notifying about tension loss on
the web.
Define the tripping level. When the observed
signal value drops below this level, the drive
assumes that the material is broken.
Define the tripping delay timer. For the drive
to trip, the web loss condition stays valid as
long as set with this timer.
The Friction compensation function improves the accuracy of tension control when no tension
feedback device is available, that is running in Open loop tension control mode.
• Static friction means the forces of mechanical friction between the construction parts that
interlock and prevent any relative motion until the limit where the motion occurs.
• Dynamic (linear) friction means an additional friction loss component as a function of roll
speed.
For information on Friction measurement procedure and parameter settings, see parameter
description in group 79 Mechanical losses compensation
Set the values of static and dynamic friction
in group 79 Mechanical losses
compensation. For more information, see
page 442.
Start-up guide for ACS880 winder control program 35
Safety function settings
Friction compensation settings
81.01 Web-loss function
81.02 Web-loss sensor src
81.04 Speed error low %
81.09 Open-loop trip delay
81.19 Closed-loop trip delay
(page 442).
79.12 Static friction torque
79.13 Friction torque at 5% speed
79.14 Friction torque at 10% speed
79.15 Friction torque at 20% speed
79.16 Friction torque at 40% speed
79.17 Friction torque at 60% speed
79.18 Friction torque at 80% speed
79.19 Friction torque at 100% speed