Siemens SINUMERIK 840D sl Function Manual page 137

Figure 3-12
Contour elements
The following contour elements are permissible:
● G0, G1 for straight contour elements
● G2 for circle segments in the clockwise direction
Permissible only for workpiece-related protection zones.
Not permissible for tool-related protection zones because they must be convex.
● G3 for circular segments in the counterclockwise direction
A protection zone cannot be described by a complete circle. A complete circle must be divided
into two half circles.
The sequence G2, G3 or G3, G2 is not permitted. A short G1 block must be inserted between
the two circular blocks.
Constraints
During the definition of a protection zone, the following functions must not be active or used:
● Tool radius compensation (cutter radius compensation, tool nose radius compensation)
● Transformation
● Reference point approach (G74)
● Fixed point approach (G75)
● Dwell time (G4)
● Block search stop (STOPRE)
● End of program (M17, M30)
● M functions: M0, M1, M2
Programmable frames (TRANS, ROT, SCALE, MIRROR) and configurable frames (G54 to G57)
are ineffective.
Basic Functions
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Examples: convex and concave tool-related protection zones
A3: Axis Monitoring, Protection Zones
3.3 Protection zones
137