Speed/Torque Select - Allen-Bradley PowerFlex 70 Reference Manual

Speed/Torque Select

Speed/Torque Select
172
value of zero. Units are (per unit torque) / (per unit speed). For example, when
[Kp Speed Loop] is 20, the proportional gain block will output 20% motor rated
torque for every 1% error of motor rated speed.
Feed Forward Gain
FV
Vector
The first section of the PI regulator is the feed forward block. [Kf Speed Loop]
allows the speed regulator to be dampened during speed changes. To reduce
speed overshoot, reduce the value of [Kf Speed Loop]. During auto-tune, the
feed forward is left open (no dampening).
Speed Desired BW
Vector FV
[Speed Desired BW] sets the speed loop bandwidth and determines the dynamic
behavior of the speed loop. As bandwidth increases, the speed loop becomes
more responsive and can track a faster changing speed reference. Adjusting this
parameter will cause the drive to calculate and change [Ki Speed Loop] and [Kp
Speed Loop] gains.
Total Inertia
FV
Vector
[Total Inertia] represents the time in seconds, for a motor coupled to a load to
accelerate from zero to base speed, at rated motor torque. The drive calculates
Total Inertia during the autotune inertia procedure. Adjusting this parameter will
cause the drive to calculate and change [Ki Speed Loop] and [Kp Speed Loop]
gains.
[Speed/Torque Mod] is used to choose the operating mode for the
Vector FV
drive. The drive can be programmed to operate as a velocity regulator, a torque
regulator, or a combination of the two. Refer to
Figure 37
Scale
Torque Ref A Sel
427
Scale
Torque Ref B Sel 431
Torq Ref B Mult
Rockwell Automation Publication PFLEX-RM001H-EN-P - June 2013
Figure
Spd Reg PI Out
Ref A Hi
428
Ref A Lo
429
/
Torq Ref A Div 430
Ref B Hi
432
x
433 Ref B Lo
434
37.
Speed/Torque Mod
88
0
0
1
2
Min
3
4
Max
5
+
+ 6
abs
Min