User's Manual

PMAC User Manual
190 Writing Programs for PMAC
Programmed
Path
Tool Center
Path
Short
Arc
Executed
Compensated
Circle
“Skipped”
Programmed
Full Circle
1
1
2
3
2
Failure When Compensation Extends Full Circle
r
r
r
Figure 44 Failure When Compensation Extends Full Circle
Speed of Compensated Moves
Tool center speed for the compensated path remains the same as that programmed by the F parameter.
On an arc move, this means that the tool edge speed (the part of the tool in contact with the part) will be
different from that programmed by the fraction R
tool
/R
arc
.
Changes in Compensation
PMAC permits changes both to the radius of compensation and the direction of compensation while the
compensation is active. It is important to understand exactly how PMAC changes the compensated path
in these cases.
Radius Magnitude Changes
Changes in the magnitude of compensation (new CCR values) made while compensation is active are
introduced linearly over the next move. When this change is introduced over the course of a LINEAR-
mode move, the compensated tool path will be at a diagonal to the programmed move path. When this
change is introduced over the course of a CIRCLE-mode move, the compensated tool path will be a
spiral.
Compensation Direction Changes
Changes in the direction of compensation (between CC1 and CC2) made while compensation are
generally introduced at the boundary between the two moves.