Rockwell Automation WebPak 3000 DC Drive Application Workbook Version 1.1 - Manual (Page 59)

Configuring the Current Major Outer Control Loop 10-3
Three of the inputs to the tension-to-current scaling block are calculated by the
system:
•
NORM FIELD REF (P.130) is the normalized field reference input to the field shaping
task.
•
NORM ROLL DIAMETER (P.131) is the normalized roll diameter output of the diameter
calculator table.
• Normalized full roll diameter, which is the calculated value of roll buildup.
The remaining input is user configurable:
▲
Set MAXIMUM CURRENT (P.007) to specify the value of the drive current limit
setting in % of motor full load amps. This parameter was set during Quick
Start.
10.3 The Tension PI Input
The reference to the tension PI block is the rate-limited value of TENSION DEMAND
(P.844). The output of this block is TEN RAMP OUTPUT (P.842). Refer to figure A.19 in
Appendix A of the software manual (D2-3444). The PI block feedback is the value of
SPD LOOP OUTPUT (P.299), which is the reference to the current minor loop; therefore, it
is directly proportional to motor current.
The PI block proportional gain is set by the value of TEN PI KP OUT (P.879) as described
in section 10.1.
TEN LOOP ERROR (P.834) reads the difference between P.842 and P.299.
TEN PI LEAD FREQ (P.840) is the PI block integral gain.
þ
To configure the tension PI input:
▲
Set TEN RAMP TIME (P.833) to set the reference rate of change.
▲
Set TEN PI LEAD FREQ (P.840) initially to 40 rad/s.
10.4 The Tension PI Output
The output of the PI block is TENSION VERNIER (P.856), which is used as a trim signal on
the speed loop. Refer to figure A.19 in Appendix A of the software manual (D2-3444).
The amount of speed loop trim is set by the HI and LO limits of the PI block, which
would nominally be configured at 10%. However, product characteristics, such as
modulus of elasticity, can require more or less than 10% trim.
Range: 25 to 200% FLA P.007 = % FLA
Range: 0.1 to 60.0 SECONDS P.833 = SECONDS
Range: 0.00 to 141.37 RAD / S P.840 =
5$'6