When the axis is in Closed Loop Mode, the Target Position is the calculated instantaneous ideal position for the axis. The Target Position is calculated every loop by the target generator state machine of the on-board motion control program. The PID routine uses the difference between the Target Position and the Actual Position as its input to compute any required corrective drive.
During a move the path of the Target Position toward the Command Position will be the perfect profile for the Actual Position to follow.
Note: When an axis is stopped, the Target Position should be the same as the Command Position unless an error or HALT has occurred (see Status).
Note: When an axis is not in position Closed Loop Mode, Target Position is set to the Actual Position.
Why Bother?
Knowing the relationship between the Target Position and Actual Position is key to tuning the axis. The main goal in tuning the axis is to minimize the error between the Target and Actual Positions. The plot function is a very useful visual aid in tuning the axis.
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