Rockwell Automation 20P PowerFlex Digital DC Drive - Manual (Page 265)

Rockwell Automation Publication 20P-UM001I-EN-P - February 2013 265
Application Notes Appendix C
• Enable the current/speed curve function by setting parameter 750 [TrqTpr
Enable] to 1 “Enabled”.
• Set the current limit (for both directions of rotation in four quadrant
drives) in parameter 751 [TrqTpr Lim0]. The value specified in this
parameter overrides the value of parameters 8 [Current Lim Pos] and 9
[Current Lim Neg].
• Set the threshold speed at which current (torque) reduction begins in
parameter 756 [TrqTpr Spd].
• Set the first reduced current limit in parameter 752 [TrqTpr Lim1]. The
value defined in this parameter must be less than the value in parameter
751 [TrqTpr Lim0] and greater than the values in parameters 753 [TrqTpr
Lim2], 754 [TrqTpr Lim3] and 755 [TrqTpr Lim4].
• Set the second, third and final reduced current limits in parameters 753
[TrqTpr Lim2], 754 [TrqTpr Lim3] and 755 [TrqTpr Lim4], respectively.
The value of each subsequent parameter must be less than the previous
parameter’s value. The drive will maintain the value specified in parameter
755 [TrqTpr Lim4] up to the value set in parameter 162 [Max Feedback
Spd].
Drive Reference and
Feedback Scaling With firmware version 3.001, external reference and feedback speed values are
each normalized to 25,000 counts (for firmware version 2.005 and lower, external
reference and feedback speed values are scaled to “rpm x 4” counts).
The value of parameter 45 [Max Ref Speed] (rpm) will determine the correlation
(scaling) between DPI speed reference counts and rpm as well as the analog input
reference values (10V = Par 45 rpm). All speed reference values are based on the
value of [Max Ref Speed]. The value of [Max Ref Speed] represents the
maximum speed the motor can attain (also known as Gear-in Speed). If field
weakening is used, [Max Ref Speed] would be set to the field weakened speed.
Otherwise, the motor base speed is typically used.
The value of parameter 162 [Max Feedback Spd] (rpm) will determine the
correlation (scaling) between DPI speed feedback counts and rpm as well as the
DC tachometer values (if configured). All speed feedback values are based on
[Max Feedback Spd]. Typically, [Max Feedback Spd] is set to the same value as
parameter 45 [Max Ref Speed], but this is not required (because each is
separately scaled to 25000 counts). See Speed Feedback on page
269 for
limitations for parameter 162 [Max Feedback Spd] and 169 [Encoder PPR].