Nexen RSD250 964260 - Manual (Page 10)

FORM NO. L-21179-D-1108 10
NEw ROLL ADAPTATION
New Roll Adaptation is adjusted by rotating a potentiometer, R20, on the RSD250 printed circuit board (See Figure 6).
To increase, turn clockwise; to decrease, turn counterclockwise. Adjust New Roll adaptation one turn at a time.
NEW ROLL ADAPTATION is the beginning adaptation value that the RSD250 will adapt from after receiving a Splice
signal. The closer this value is to the actual adaptation value the shorter the time required for the RSD250 to adjust itself
to actual roll conditions; so NEW ROLL ADAPTATION needs to be set for a new roll.
NOTE: If a machine is started with a new roll smaller than the roll used to set NEw ROLL ADAPTATION, the con-
troller gain could be too high, causing the dancer arm to become unstable.
Unwind applications begin with new rolls and run them down to their core diameter. Some unwind applications start with
the same diameter roll every time; others start with rolls of various diameters. NEW ROLL ADAPTATION should be set
to the smallest diameter new roll run under minimum tension conditions.
1. Load the smallest diameter new roll on the machine and set the web tension to minimum.
2. Momentarily apply the splice signal.
3. Start the machine and note if dancer arm stabilizes quickly about its operating position.
4. If arm is unstable or takes an excessive amount of time to settle down, then decrease NEW ROLL ADAPTATION.
If arm is very sluggish to start, then increase NEW ROLL ADAPTATION. Repeat steps 2 and 4.
5. Unwind the roll and check periodically that dancer arm quickly returns to its operating position after each start up
as the roll becomes smaller.
GAIN
Note: Gain must be adjusted first, because it affects all tuning parameters and controls how the dancer arm
responds to errors.
Gain is adjusted by rotating a potentiometer, R19, on the RSD250 printed circuit board (See Figure 6). To increase, turn
clockwise; to decrease, turn counterclockwise. Adjust Gain one half turn at a time.
Figure 6
1. Operate the machine at a slow run speed with a
nearly full roll.
2. When the machine is at a constant speed, allow
about ten seconds for the RSD250 to adapt.
Rotary
Switch
Indicator
R19
R20
I4
I3
I2
I7
I1
1
W2
2
U13
a) Change the machine speed to introduce a
dancer arm disturbance. The dancer arm
will move and return to its operating position
quickly with little or no overshoot.
b) If the arm is slow to reach it operating position,
increase Gain and repeat the test.
c) If dancer arm becomes unstable after a speed
change, decrease Gain and test again.
New Roll Adaptation
Gain