Eurotherm 590SP, Product Manual

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590SP Digital Product Manual
App. M - 20
Appendix M Special Blocks and Application Notes
M
Dancer Position Applications
In dancer position applications, the controller attempts to keep the dancer stationary by varying the winder speed.
TAPER CALC. uses signals from terminals A5, TENSION SETPOINT, and A6, TAPER SETPOINT, to produce the
dancer loading. Dancer loading affects web tension by setting the force the dancer exerts on the web.
The PID setpoint, PID:: INPUT 1, is a fixed value set in the MMI representing the desired position of the dancer. The
user must remove the connection to PID:: INPUT 1 to manually set the dancer position. PID compares PID:: INPUT 1
with the actual dancer position, TENSION FEEDBACK at terminal A3. The output, PID OUTPUT, is the position
loop trim used in SETPOINT SUM 2.
Turret Winder Applications
Turret winders use two spindles to transfer the web from one spindle to the other without stopping the line. Each
spindle requires its own drive. An unwind splices from the emptying roll to a new, full roll. A rewind transfers the web
from the full roll to a new core.
To achieve this, the winders must operate in two modes, speed mode and tension mode. Speed mode is required to
match the surface speed of the new core or new, full roll to the line speed for the splice. Tension mode is required after
the splice or transfer.
Before starting in speed mode, the operator sets the diameter to core for a rewind or to the diameter of the new roll for
an unwind by inputting the correct value in terminal A2, EXTERNAL DIAMETER PRESET. Setting C7, PRESET
ENABLE, to ON keeps the diameter at the preset diameter until the transfer is completed.
Then the spindle is started using terminal C3, RUN. The drive ramps up to the correct speed so the roll’s surface speed
matches the line speed. The splice or transfer can occur at that point. When the web is transferred to the new roll or
core, tension mode is enabled by setting terminal C8, TENSION ENABLE, to ON and the old roll is stopped. At this
point, C7 is set OFF to allow the diameter calculator to calculate the correct diameter. The new roll continues in ten-
sion mode until the next roll change.
Figure M.15 - Rewind SPW Application with Dancer Position Feedback