Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual - Manual (Page 141)

Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011 141
Detailed Drive Operation Chapter 1
Parameter 72 [Scaled Spd Fdbk] provides a user scalable speed feedback. It is
multiplied by the value in parameter 73 [Spd Fdbk Scale].
Position Feedback
Parameter 777 [PositionFdbk Sel] selects the position feedback device for the
position control loop. The feedback device used for position control may be an
independent selection from the motor speed control feedback device in Par 222
[Mtr Fdbk Sel Pri]. If the position feedback will be the same as the Motor
feedback, select option 3 “Mtr Fdbk Pri” (default value) in [PositionFdbk Sel].
This selection will set the selected feedback of Par 222 [Mtr Fdbk Sel Pri] as the
Position regulator’s position feedback. The following options are available:
Note: Options 5 and 6 are only available when compatible feedback option card
is installed.
Speed Feedback Loss Ride Through
The speed feedback loss ride through function provides an automatic switch over
from the primary motor speed feedback device to the alternate motor speed
feedback device when a primary motor speed feedback device fault is sensed.
When this feature is not active, the drive will automatically switch from an
encoder to sensorless operation in the event of a primary encoder failure. When
an alternate speed feedback device other than “Sensorless” has been selected and
has failed, the switching will not be allowed and the drive will fault. The active
device can be monitored and manual switching between the primary and
alternate devices is available. This function is also referred to as “tach loss switch
over” and “encoder loss ride through.”
0 = “Encoder 0”
1 = “Encoder 1”
3 = “Mtr Fdbk Pri”
4 = “Motor Sim”
5 = “FB Opt Port0”
6 = “FB Opt Port1”
LPass
Filter X
300
73
72
Motor Spd Fdbk
Scaled Spd Fdbk
to Speed Control
To HIM Display
Spd Fdbk Scale