Rockwell Automation 1395 Digital DC Drive FRN 5-10.10/9.30 - Manual (Page 234)

Chapter 7
Programming Parameters
7-68
Parameter 741– Desired Current Loop Bandwidth [Cur Desired
BW]
Internal units : None
Programming Terminal units: RAD/Sec.
Minimum Value: 40
Maximum Value: 1000
Default Value: 500
Description: This parameter specifies the armature current loop
bandwidth requested by the user and determines (along with
Parameter 743) the dynamic behavior of the current loop.
The desired bandwidth is limited to the maximum achievable
bandwidth which is calculated by the current processor (CP). The
current loop becomes more responsive and reproduces the current
reference more accurately as the bandwidth is increased. However,
the current may exhibit more noise and overshoot as the current loop
bandwidth is increased. Typically, the bandwidth should be set as
high as possible so that the velocity loop performance is not limited
by the current loop.
Parameter 742 – Maximum Current Loop Bandwidth [Cur Max
BW]
Internal units : None
Programming Terminal units: RAD/Sec
Minimum Value: 40
Maximum Value: 1000
Default Value: 500
Description: This parameter specifies the maximum achievable
armature current loop bandwidth as calculated by the CP. The
maximum bandwidth as calculated by the CP. The maximum
bandwidth is a function of the current loop damping factor (Parameter
743) and the AC line frequency. The CP updates this Parameter
during autotuning and whenever the user reads this parameter. The
maximum current loop bandwidth is not changeable by the user.
Parameter 743 – Current Damping Factor [Cur Damp Factor]
Internal units : None
Programming Terminal units: None
Minimum Value: 0.8
Maximum Value: 3.0
Default Value: 1.0
Description: This parameter (along with Parameter 741) determines
the dynamic behavior of the armature current loop. The damping
factor influences the amount of overshoot the current loop will exhibit
during a transient. The current will typically exhibit more overshoot
and become oscillatory (underdamped) as the damping factor is
reduced below one. For a damping factor above one, armature
current loop should not exhibit much overshoot and have a slower
rise time for a given current loop bandwidth.