Chapter 6 Arc Moves
NI-Motion User Manual 6-2 ni.com
To move axes in a circular arc, the motion controller needs the following
information:
•Radius—Specifies the distance from the center of the arc to its edge
•Start Angle—Orients the arc on its plane using the starting point as an
axis to spin around. Because the starting point for a new arc is fixed
based on the current position, moving its center around the starting
point alters the orientation of a new arc. For example, Figure6-2 shows
the effect of changing the start angle from 0° to 180°.
Figure 6-2. Rotating Start Angle
•Travel Angle—Indicates how far the arc travels in a 360°circle. For
example, a travel angle of 90° executes a quarter-circle, a travel angle
of 360° creates a full circle, and a travel angle of 720° creates two full
circles. A positive travel angle always creates counterclockwise
circular motion. A negative travel angle reverses the direction to create
clockwise circular motion, as shown in Figure6-3.
1 Original Arc 2 Arc with 180° Start Angle
0°180°
1
2