
Chapter 4 What You Need to Know about Moves
NI-Motion User Manual 4-2 ni.com
Figure 4-1.  Trapezoidal Move Profile
S-CurveThe acceleration and deceleration portions of an s-curve motion profile are 
smooth, resulting in less abrupt transitions, as shown in Figure 4-2. This 
limits the jerk in the motion control system, but increases cycle time. The 
value by which the profile is smoothed is called the maximum jerk or 
s-curve value.
Figure 4-2.  S-Curve Move Profile
Basic MovesThere are four basic move types:
•Reference Move—Initializes the axes to a known physical reference 
such as a home switch or encoder index
•Straight-Line Move—Moves from point A to point B in a straight 
line. The move can be based on position or velocity
•Arc Move—Moves from point A to point B in an arc or helix
Velocity
Time
Velocity
Time