Siemens SINUMERIK 802D sl Programming And Operating Manual page 230

Programming
10.3 Axis movements
Input tolerances for the circle
Circles are only accepted by the control system with a certain dimensional tolerance. The
circle radius at the starting and end points are compared here. If the difference is within the
tolerance, the center point is exactly set internally. Otherwise, an alarm message is issued.
The tolerance value can be set via machine data (see "Operating Instructions" 802Dsl).
Information
Full circles in a block are only possible if the center point and the end point are specified.
For circles with radius specification, the arithmetic sign of CR=... is used to select the correct
circle. It is possible to program two circles with the same starting and end points, as well as
with the same radius and the same direction. The negative sign in front of CR=-...
determines the circle whose circle segment is greater than a semi-circle; otherwise, the circle
with the circle segment is less than or equal to the semi-circle and determined as follows:
Figure 10-17 Selection of the circle from two possible circles with radius specification using the sign of
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CR=
Programming and Operating Manual, 11/2012, 6FC5398-5CP10-3BA0
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