HEIDENHAIN ND 1300 VED and Crosshair Systems - Manual (Page 108)

88 QC-300 Series User’s Guide
Probing lines
A minimum of two probed points is required to measure a line. There is no practical limit to the number of
points that can be probed, and in general accuracy is increased by probing more points.
When only two points are probed, Measure Magic will correctly recognize a line and assign the correct
feature. However, when more than two points are probed, it is possible that the wrong feature type will
be assigned. If the wrong feature type is assigned, it can easily be changed by selecting the correct feature
from a menu of alternatives in the DRO window.
Best-fit algorithms are used to define lines when more than two points are probed. The line fit to the probed
data can also be changed by selecting the desired fitting algorithm from a menu in the DRO window.
Please refer to Chapter 13: Reference Materials for details regarding the fitting algorithms.
Measurement results are shown in the Features list, View window and DRO window. Results are also
shown in the DRO overlay. The feature graphic in the View window shows the feature and the points used
to define it. Errors are shown as whiskers connecting the probed points to the feature. The maximum errors
are shown in red and are used in the calculation of form. The DRO window shows the number of points
used, the angular orientation of the line, the coordinate location of the center of the line and the form error.
When only two points are probed, the form error is zero. When more than two points are probed, the form
error is the sum of the two greatest opposing error magnitudes.
Three points are probed to measure a line
Touch the feature type... to display the menu of alternative
types
Probed points are shown in the
View window