306 Rockwell Automation Publication MOTION-RM003I-EN-P - February 2018
Usage Access Data
Type
Default Min Max Semantics of Values
* Ind
icates the attribute cannot be set while the drive power structure is enabled (Power Structure Enable bit in CIP Axis Status
is true).
The Feedback Mode attribute determines how the various available feedback
channels are used to implement the selected Control Mode. This attribute is
transferred to the device as part of the Cyclic data block. Currently only bits 0-3
are used to enumerate the Feedback Mode configuration.
Feedback Mode enumerations provide support for multi-feedback device control
functionality for the various active device Control Modes, for example, where the
device is actively controlling the motor based on feedback. In these active device
Control Modes it is assumed that logical channel, Feedback 1, is attached directly
to the motor while Feedback 2 is attached to the load side of the mechanical
transmission. Commutation signals for a PM motor are always derived from the
Feedback 1, except in the case of an active redundant feedback source.
Bit Usage Name Description
0 R/S No Feedback
No
Feedback is selected when sensorless open loop or closed loop control
is desired. When performing open loop control, no feedback signal is
required. In closed loop control, the required feedback signal is
estimated by a sensorless control algorithm based on motor phase
voltage and current signals.
1 R/N Master Feedback
Master Feedback assigns an uncommitted feedback channel to this
device axis instance to serve as a master feedback source when the
device is configured for No Control mode.
2 R/C Motor Feedback
When Motor Feedback is selected, then commutation, acceleration,
velocity, and position feedback signals are all derived from motor
mounted Feedback 1.
3 O/C Load Feedback
When Load Feedback is selected, then motor-mounted Feedback 1 is
only used for PM motor commutation while load-side Feedback 2 is used
for position, velocity, and acceleration.
4 O/P Dual Feedback
When Dual Feedback is selected, then motor mounted Feedback 1 is
used for commutation, acceleration, and velocity, and load-side
Feedback 2 is used strictly for position.
5-7 - Reserved -
8 O/P Dual Integrator Feedback
Dual Integral Feedback means that motor-mounted Feedback 1 is used
for commutation, acceleration, velocity, and position proportional
control, and load-side Feedback 2 is used only for integral position
control. This optimizes the stiffness of the control loop at low frequency.
9-15 - Reserved -
When modified programmatically, using SSV, the Feedback Mode value cannot be
set to an enumeration that the Feedback Configuration cannot support. For
example if the Feedback Configuration is set for Motor Feedback, the Feedback
Mode cannot be changed to Load Feedback since that feedback channel has not
been configured.
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