Nexen RSTC1100 964528 - Manual (Page 22)

FORM NO. L-21204-C-0908 22
Acceleration Acceleration
Run Speed Run Speed
Deceleration Deceleration
Stopped
Run/Stop Signal
Web Speed
Splice
Signal
Splicing Adaptation
Initial Adaptation &
Small Roll Large Roll
Adaptation
SPLICING WIND APPLICATION
The RSTC utilizes “Smart Splicing” when transitioning to a
new roll on a web. This means that rolls of different sizes
can be loaded or spliced into the machine without having to
readjust the controller. The RSTC will adapt automatically
to the new roll after receiving the splice signal. When
the splice input pulses high, the controller will reset the
adaptation to the level defi ned by Splice Adaptation. The
splice input can be used anytime a new roll is loaded on
the machine and the machine can be running or stopped.
The splice input must be held high for at least 100 ms for
the RSTC to detect this signal. The adaptation process will
begin immediately if the machine is running or will begin
after the RSTC receives a Run signal. Typically the SPLICE
ADAPTATION value is set to the same value as INITIAL
ADAPTATION for winding applications. At the time of the splice, the RSTC must receive a Splice
A or Splice B signal. This will cause the corresponding
control output to become the active output that controls the
web tension. If the new roll is to be controlled by Output B,
then the splice signal is given to the Splice B input. After
the splice signal is received, the opposite control output
goes into standby mode which causes the output to remain
at a constant level as specifi ed by Standby Output.
Figure 28
WIND APPLICATION
A typical winding application begins at core. The INITIAL
ADAPTATION value should be set high enough to allow
the tension setpoint to be reached quickly after the Run
signal is given. Many winders are started before the
machine begins to move the web. This is not a problem
as the winder is active, even at zero web speed, and the
RSTC can control tension while in Run mode without the
adaptation process adjusting the gains too high.
As the roll begins to accelerate, the web tension will settle
on a level determined by Tension Setpoint. Next, the roll
will continue to increase in size along with the Adaptation
and Output values. It is normal for the RSTC’s output value
to fl uctuate as long as web tension does not.
During a machine stop, Adaptation and Output values
will initially increase to overcome a roll’s inertia. It is
normal for the RSTC to remain in Run mode throughout
the deceleration and while the web is at zero speed as
long as the web tension is capable of being controlled.
Otherwise, the RSTC must go into Stop mode after the
web has stopped moving.
Tapering of the winding tension is possible with the addition
of a diameter sensor or signal that can provide a diameter
reference for the RSTC. Refer to Taper Tension in the
TUNING section for more information.