Eurotherm 590SP, Product Manual

Page: 240 / 259

590SP Digital Product Manual
App. M - 19
Appendix M Special Blocks and Application Notes
M
CLOSED-LOOP SPEED PROGRAMMED WINDER (SPW)
A speed programmed winder, SPW, provides closed-loop center winder control. It programs the motor speed using
either loadcell or dancer feedback for tension control.
This configuration provides standard features used in center winder applications including: diameter calculation with
memory and preset, tension and taper, PID for loadcell tension or dancer position control, and over/under winding. It
can control unwinds or rewinds for single-spindle and turret winders. The configuration uses four function blocks in
the SPECIAL BLOCKS; DIAMETER CALC., TAPER CALC., SETPOINT SUM 2, and PID.
Description
Figures M.15 and M.16 show typical SPW applications. SPW applications use closed-loop trim to modify the winder
speed. Line speed is conditioned in RAMPS before being combined with the tension trim in SETPOINT SUM 2. The
result, SPT. SUM OUTPUT, is scaled by DIAMETER and MIN DIAMETER in SETPOINT SUM 1 to produce the
speed demand.
TAPER CALC.:: TOT. TENS DEMAND uses inputs to terminals A5, TENSION SETPOINT, and A6, TAPER SET-
POINT, to produce a diameter compensated tension demand. It produces either the tension setpoint for loadcell appli-
cations or dancer loading signal for dancer applications. TAPER SETPOINT is not used in unwind applications.
Terminal C6, OVERWIND, switches the speed demand sign for overwinding or underwinding. The winder can change
directions by changing the LINE SPEED signal at terminal A4 to the opposite sign.
Loadcell Applications
In loadcell applications, the controller attempts to keep the tension at the loadcell constant by varying the winder
speed. The setting at terminal A5, TENSION SETPOINT, sets the desired loadcell tension. In TAPER CALC., the ten-
sion setpoint is compensated for diameter and taper. The output, TOT. TENS DEMAND, is the PID setpoint signal at
PID:: INPUT 1.
PID compares the setpoint, PID:: INPUT 1, with TENSION FEEDBACK from terminal A3. The output, PID OUT-
PUT, is the tension loop trim used in SETPOINT SUM 2.
Figure M.14 - Unwind SPW Application with Loadcell Feedback