HEIDENHAIN IK 5494-2D - Manual (Page 170)

148 QC5200 Series User’s Guide
Arcs
A minimum of three probed points is required
to measure an arc. There is no practical limit
to the number of points that can be probed,
and in general accuracy is increased by prob-
ing more points.
When the arc is less than 185 degrees, Mea-
sure Magic will correctly recognize the arc
feature. However, when the arc is 185 degrees
or more, it is likely that Measure Magic will
assign the circle fea-
ture type to the data.
If the wrong feature
type is assigned, it can easily be changed by right-clicking the Results window and
selecting the arc feature alternative.
Measurement results are shown in the Features template, Part View window and Results window. The
Results window shows the feature identification number, the number of points used in the measurement,
the radius, diameter and length of the arc, the coordinate location of the center of the arc and the form error.
When only the three required points are probed, the form error is zero. When more than three points are
probed, the form error is the sum of the two greatest opposing error magnitudes.
Click the feature stamp icon
in the left corner of the Re-
sults window to display the
Feature Stamp window. The
arc will be shown with data
point form errors in blue, fil-
tered points in yellow and the
greatest two opposing form
errors in red.
Eighty five points are probed using the Circle probe to
measure an arc feature