Introduction – Nexen TCD600E 912145 User Manual

Page 4

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FORM NO. L-20348-F-0705

4

FIGURE 1

The Nexen TCD 600 is a non-contact open loop tension
control system that provides reliable web tension control
that’s easy-to-use and requires minimum attention by the
operator.

The TCD 600 maintains constant tension by varying the brake
or clutch torque with the change in roll diameter. When the
set point is adjusted for the maximum torque needed at full
roll diameter, the TCD 600 applies a correction based on
its diameter calculation and proportionately increases clutch
torque as a wind roll builds up, or decreases brake torque
as an unwind roll becomes smaller.

For example, Figure 1 shows a system that includes a sensor,
which measures the diameter of the roll. The sensor sends
this information to the TCD 600 Controller. An operator
enters into the TCD 600 the maximum and minimum size
of the roll, along with other information that applies to the
specific job. The TCD 600, using this information, varies
the amount of torque applied to a brake or a clutch as the
roll diameter changes. As a result, a constant tension is
maintained on the web. This example is only one of the
many potential control systems that can be built around
the TCD 600.

The TCD 600 will work with three different sensor configu-
rations: Ultrasonic Sensor, Proximity Switch, and Proximity
Switch - Optical Encoder combination. The Ultrasonic Sensor
configuration measures roll diameter directly (See Figure 2).
The Proximity Sensor configuration counts the number of roll
revolutions. This value, plus the web thickness, enables the
TCD 600 to estimate the roll diameter (See Figure 3). The
Proximity Switch - Optical Encoder combination accurately
calculates the roll diameter by measuring the amount of web
paid out for each revolution of the roll.

The TCD 600 provides three output signals: two for control,
4-20 mA and 0-10 VDC, and one for monitoring, 0-5 VDC. The
4-20 mA output signal is typically used with Nexen Electro-
Pneumatic Converters to vary the air pressure applied to air
actuated tension brakes and clutches. The 0-10 VDC output
signal is often used as a speed or torque reference voltage
for motor drive controllers or is used with power supplies
for electric brakes or clutches. The 0-5 VDC output signal
provides a way to remotely monitor roll diameter; 0 VDC
corresponds to the roll core, and 5 VDC corresponds to a
maximum diameter roll. In addition, two contact outputs are
available for use as user specified minimum and maximum
roll diameter alarm outputs.

TCD 600

FIGURE 2

FIGURE 3

FIGURE 4

SENSOR

BRAKE

OR CLUTCH

PROXIMITY

SWITCH

TARGET

PROXIMITY

SWITCH

TARGET

OPTICAL

ENCODER

ULTRASONIC

SENSOR

Output to brake for Unwind

applications, or to clutch for

Wind applications.

INTRODUCTION

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