Rockwell Automation 9329 Drive Application Software Tension Control Gen. Units - Manual (Page 45)

FM – Tension Control
Drive Application Software – page 45 of 52
6.4 Dancer Regulation
6.4.1 Trimming Speed:
The TrimLimSpd_Pct is the maximum output of the trim regulator when the line
speed is at maximum. This value should typically be ten percent. When the line
speed is zero the TrimLimSpdZero_Pct is the maximum output of the trim regulator.
This value is typically set to one percent. This allows the trim regulator to operate
even though the line velocity is at zero.
When the Trim Regulator is trimming speed, the following calculations will give the
user a starting point for the various gains. The output of the trim regulator should be
limited to about ten percent.
There are some specific starting points for dancer regulation. To calculate these
gains there are some specific information that is required. The first piece of
information required is the amount of material that the dancer can store. The user
can usually determine this information from the mechanical drawings. An empirical
method, is to measure the distance traveled by the "swing roll" and multiply by two.
All data for the following calculations must be entered in like units (Imperial or Metric).
A. Amount of material stored in linear measurement:-______________
Units must be the same as the linear measurement in line “B”
Convert the tag value of LineSpeedMax_EU into the units of linear
measurement/second. Example: If the tag units are feet/min then divide by 60 to get
feet/second.
B. Linear Speed/Second:_________________________
C. Dived line “A” by “B”, Pbar = _____________ in seconds
D. Enter the desired Bandwidth for the Dancer Regulator, BW = _________rad/sec
This is typically 1/5 th the bandwidth of the speed regulator.
E. Multiply line “C” by “D” (Pbar*BW) to Solve for TrimKP = ___________
F. Trim_wld=TrimKP/zeta
(zeta) is typically set for 1, a setting less than 1 will cause more overshoot, and a
value greater than 1 will have less overshoot (increased dampening).
G. TrimFB_wld=p97 system bandwidth from the PowerFlex 700S
H. TrimFB_wlg=5*TrimFB_wld
After the initial values are set, the user may have to adjust (tune) these initial values
for desired performance.
6.4.2 Trimming Torque
When the regulator is trimming torque, the TrimTorqueLimit is typically set to 10%.
The user will need to begin by setting the TrimFB_wld and TrimFB_lag to 10. The
Trim_wld term is set to zero. The user should increase the TrimKP term until the
system appears to oscillate and then reduce the TrimKP by 50%. At this point, there
will be a steady state error. Adjust Trim_wld to decrease the steady state error.
Begin decreasing the TrimFB_wld from 10 to 5 to 1 until the desired response is
achieved.