National Instruments NI-Motion User Manual page 57

Chapter 5 Straight-Line Moves
You must load the move constraints only if they are different from what was
Tip
previously loaded.
NI-Motion User Manual
The start position is always the current position of the axis or axes. You can
load the end position as either an absolute position to move to or as a
position relative to the starting position. Although you can update any
parameter while the move is in progress, the new parameter is used only
after a subsequent Start or Blend Move.
Figure 5-1. Position-Based Straight-Line Move Algorithm
5-2 ni.com