FeedbackFault

FeedbackFault

Applies to: Servo and Servo Drive axes.
FeedbackFault is a Boolean attribute. Its cause and significance depends upon the axis type.
For Servo axes:
FeedbackFault is set for a specific feedback source if one of the following events occur:
  • The differential electrical signals for one or more of the feedback channels (e.g., A+ and A-, B+ and B-, or Z+ and Z-) are at the same level (both high or both low).
    Tip:
    Under normal operation, the differential signals are always at opposite levels. The most common cause of this situation is a broken wire between the feedback transducer and the servo module or drive.
  • Feedback "power" or feedback "common" electrical connection has been lost between the servo module or drive and the feedback device.
FeedbackFault is a recoverable condition. To clear a FeedbackFault for a Servo axis be sure your program or fault handling routine contains either an MAFR (Motion Axis Fault Reset) or MASR (Motion Axis Shutdown Reset) instruction.
The occurrence of a FeedbackFault on a Servo axis sets bit #4 of the ServoFault attribute, the PhysicalAxisFault attribute and bit #0 of the AxisFault attribute.
For Servo Drive axes:
FeedbackFault is a higher-level fault that is set if either the MotFeedbackNoiseFault or AuxFeedbackFault attribute is set.
FeedbackFault is a recoverable condition.
To clear a FeedbackFault for a Servo Drive axis:
  1. Fix the motor or auxiliary feedback connection or device.
  2. Be sure your program or fault handling routine contains either a:
    • Fault Reset (MAFR) instruction, to clear all motion faults for an axis, or
    • Shutdown Reset (MASR or MGSR) instruction to return to the axis ready operating state.
The occurrence of a FeedbackFault on a Servo Drive axis sets bit #21 of the DriveFault attribute, the PhysicalAxisFault attribute and bit #0 of the AxisFault attribute.
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