Rockwell Automation WebPak 3000 DC Drive Application Workbook Version 1.1 - Manual (Page 70)

12-2 WebPak 3000 DC Drive Application Workbook, Version 1.1
▲ Set TENSION / DANCER GAIN (P.417) to adjust the gain of the analog input signal
if necessary.
▲ If necessary, set TENSION / DANCER ZERO (P.416) to adjust the zero point of the
analog input signal.
TENSION / DANCER FDBK (P.493) is the value of the analog signal used for tension
feedback to the PI block. Note that this is the same analog input that would have been
used for a position feedback signal, if the drive had been configured with a position
outer control loop.
12.1.1 The SCALE Block
The tension feedback signal is conditioned by a SCALE block. Refer to figure A.18 in
Appendix A of the software manual.
þ
To set up the SCALE B lock:
▲ Set TENSION FDBK MIN (P.852) to set IN _ MIN .
▲ Set TENSION FDBK MAX (P.851) to set IN _ MAX .
The output of the SCALE block is TEN / DANCER FDBK SCALED (P.489). See the following
examples for more information on setting up the SCALE block.
Range: 0.750 to 2.250 P.417 =
Range: -3000 to 3000 P.416 =
Range: -4095 to 4095 COUNTS P.852 = COUNTS
Range: -4095 to 4095 COUNTS P.851 = COUNTS
Setting Up the Scale Block
The setting for TENSION FDBK MIN (P.852) and TENSION FDBK MAX (P.851) depend on
the characteristics of the tension feedback signal.
The output of the SCALE block will go from 0 to 4095 counts as the load cell goes
from zero tension to maximum tension. Typically, the tension feedback signal will be
zero at zero tension and maximum at maximum tension.
Example 1
If the tension feedback signal can be set, by external calibration and/or analog input
calibration, so that
TENSION / DANCER FDBK (P.493) is 0 to 10 volts as the tension goes
from minimum to maximum tension, then TENSION FDBK MIN (P.852) would be set to
0, and TENSION FDBK MAX (P.851) would be set to 4095.
Example 2
The tension feedback signal (analog input) goes from 1.0 volts to 8.0 volts as the
tension goes from minimum to maximum, and
TENSION / DANCER FDBK (P.493), which
is the digitized equivalent, goes from 409 to 3276. In this example, TENSION FDBK
MIN (P.852) would be set to 409 and TENSION FDBK MAX (P.851) would be set to
3276.