This topic describes incremental and absolute axes. The feedback type of most axes determines whether it is incremental or absolute. Only position axes with SSI or Resolver feedback can be either.
Absolute Axes
An absolute axis has a feedback type that provides absolute information. That is, it always knows its exact position. When the RMC powers up, the position is known. For example, the voltage or current from an analog input will always tell exactly where the axis is located.
Incremental Axes
An incremental axis has a feedback type that provides only information about how much it has incremented. When the RMC powers up, it has no information about where the axis is, but it can keep track of how much the position changes. Incremental axes typically need to be homed so the position is known.
Quadrature inputs are always incremental.
By Axes Type
The following feedback types are always absolute:
Position with MDT or analog feedback
Velocity
Acceleration
Pressure
Force
The following feedback types can be either incremental or absolute:
Position with SSI or Resolver feedback
To define these axis types as incremental or absolute, use the Absolute/Incremental axis parameter.
The following feedback types are always incremental:
Position with Quadrature feedback
See Also
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