Rockwell Automation Publication MOTION-RM003I-EN-P - February 2018 309
In the case of a motor mounted feedback device, if Motor Data Source is Motor
NV or Drive NV, the Feedback 1 Type may not be known to the controller but is
known by the drive, so the drive can operate in this case without specifying the
Feedback 1 Type.
In the case of a motor mounted feedback device, if the Motor Data Source is
Datasheet or Database, an unspecified Feedback 1 Type, when received by the
drive device during configuration, indicates that the motor feedback configuration
has not been defined and therefore results in a Configuration Fault indicating an
Invalid Attribute Value.
Feedback n Polarity
Usage Access Data
Type
Default Min Max Semantics of Values
Optional - E Set/SSV
*
USINT 0 - - Enumeration
0 = Normal Polarity
1 = Inverted Polarity
2...225 = Reserved
* Indicates the attribute cannot be
set while the drive power structure is enabled (Power Structure Enable bit in CIP Axis Status is
true).
The Feedback n Polarity attribute is an enumerated value used to establish the
direction of change in the feedback counter in response to positive motion of the
associated feedback device. Normal polarity is defined as that which results in
increasing feedback counts when the feedback device is hooked up and moved in
the positive direction according to the devices published specifications.
Inverted polarity internally switches the polarity of the feedback accumulator so
that the feedback counts decrease when the feedback device moves in the positive
direction. This attribute can be used to make the direction of travel agree with the
user's definition of positive travel and can be used in conjunction with the Motor
Polarity bit to provide negative feedback, when this feedback channel is used for
closed loop control.
Feedback n Startup Method
Usage Access Data
Type
Default Min Max Semantics of Values
Required - E Set/GSV USINT
Default
Startup
Method
DB
- - Enumeration
0 = Incremental (R)
1 = Absolute (O)
2...255 = Reserved
The Feedback n Startup Method attribute determines how the device applies the
feedback count value during drive startup. When configured for Incremental
mode, the device zeros the feedback count accumulator at power-up. The first
Actual Position value sent to the controller in the Cyclic Data Block of the
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