Nexen TCD600E 912145 - Manual (Page 20)

FORM NO. L-20348-F-0705 20
OVERVIEW
The TCD 600 is an open loop controller that maintains
constant tension by changing its output as the diameter
of the roll changes. This controlled output can be used for
wind or unwind applications. The TCD 600 can be used to
control air-actuated clutches and brakes or as a trim signal
to control motor drives. The TCD 600 can calculate the
roll diameter by using any of three sensor configurations:
Ultrasonic, Proximity, or Proximity-Encoder.
The TCD 600's Setpoint determines the amount of output
to be applied to the brake, clutch or drive at maximum roll
diameter (See Figure 33). If the Setpoint is adjusted to
maximum, 100%, then maximum output will be applied when
the roll is at its maximum diameter. When the Setpoint is
adjusted for less than maximum, the output at maximum roll
diameter will be proportionately less. This Setpoint value
can be changed during actual operation by using the plus
or minus buttons to increase or decrease the Setpoint to
fine tune the tension.
To maintain constant tension, it is necessary to vary the
output level with the change in roll diameter. The TCD 600
applies a correction based upon a diameter calculation and
proportionately increases the output level as a wound roll
builds up, or decreases the output level as an unwind roll
becomes smaller.
The Setpoint setting will be different for each type and each
width of material run on a specific machine. Therefore, Set-
point must be determined by experimentation. As experience
is gained on a particular machine, determining the Setpoint
for a given job will become easier.
Output level (as illustrated in Figure 33) is decreased all
the way to theoretical zero diameter. Of course, the roll only
decreases to core diameter; thus, there is a positive output
level applied at the core diameter, allowing constant tension
control from maximum roll diameter down to the core.
Some winding operations require taper tension, a relatively
higher web tension applied at the core which gradually de-
creases as the wound roll builds in size (See Figure 34).
In order to have taper tension, the torque of the winding clutch
or motor must still increase with roll diameter, but not as much
as would be required to maintain constant tension.
Taper tension is achieved by adjusting the Taper setting in
the Job Edit mode. The Taper range can be adjusted from 0
to 86.5% of the tension Setpoint. Due to the vast variety of
applications involving many different materials, the only way
to find the right amount of Taper is through experimentation.
Too little Taper will yield telescoped rolls, and too much Taper
will yield soft rolls.
FIGURE 33
FIGURE 34
OPERATION
(continued...)
0 CORE
O
U
T
P
U
T
Output Levels
at Core Diameter
100%
MAXIMUM
50%
25%
S
E
T
P
O
I
N
T
25%
50%
100%
{
ROLL
DIAMETER
CONSTANT
T APER
0 CORE ROLL
T
E
N
S
I
O
N
0
DIAMETER
OD