The control uses these functions to approach a contour on a circular path with tangential connection. You use APPR CT to define the starting point of the contour with Cartesian coordinates, and APPR PCT for polar coordinates.
Application
Description of function

- The control approaches the contour as follows:
- On a straight line from the starting point PS to an auxiliary point PH
- On a circular path that tangentially transitions to the first contour element, from the auxiliary point PH to the first contour point PA
The circular path from PH to PA is defined by center angle CCA and radius R. The direction of rotation of the circular path depends on the active radius compensation and the algebraic sign of radius R.
The table shows the relationship between the radius compensation, the algebraic sign of the radius R, and the direction of rotation:
Radius compensation | Algebraic sign of R | Direction of rotation |
---|---|---|
RL | Positive | Counterclockwise |
RL | Negative | Clockwise |
RR | Positive | Clockwise |
RR | Negative | Counterclockwise |
- The following applies regarding the center angle CCA:
- Only positive input values
- Maximum input value 360°
Programming APPR CT and APPR PCT
If you want to program this path shape with polar coordinates, then you must first define a pole CC.
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Notes
- If you enter a negative value for the radius R, the position of the auxiliary point PH changes.
- If you program R0, the control stops the machining/simulation with an error message. This behavior differs from the iTNC 530 control.
Example APPR CT
11 L X+40 Y+10 R0 FMAX M3 | ; Approach PS without radius compensation |
12 APPR CT X+10 Y+20 Z-10 CCA180 R+10 RR F100 | ; PA with radius compensation RR, radius of the circular path: R 10 |
13 L X+20 Y+35 | ; End point of first contour element |
14 L ... | ; Next contour element |