Chapter 6
Arc Moves
6-2
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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, Figure 6-2 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 Figure 6-3.
1
Original Arc
2
Arc with 180° Start Angle
0
°
180
°
1
2
