Siemens sinumerik 840D sl Function Manual page 649

Detailed description
2.2 Definition of terms
2.2 Definition of terms
2.2.1 Units and directions
Lengths and angles
In the transformation machine data, all lengths are specified in millimeters or inches and,
unless otherwise stated, all angles in degrees at intervals of [ -180°, 180° ].
Direction of rotation
In the case of angles, arrows in the drawings always indicate the mathematically positive
direction of rotation.
2.2.2 Definition of positions and orientations using frames
In order to make a clear distinction from the term "frame" as it is used in the NC language,
the following description explains the meaning of the term "frame" in relation to the handling
transformation package.
Frame
A frame can be used to translate one coordinate system into another. In this respect, a
distinction must be made between translation and rotation. Translation only effects an offset
between the coordinate system and the reference system, while rotation actually rotates the
coordinate system in relation to the reference. Coordinates X, Y and Z are used to describe
the translation. They are defined so as to result in a legal coordinate system.
Translation
The translation is always specified in relation to the coordinate directions of the initial
system. These directions are assigned to machine data as follows:
• X direction: ..._POS[0]
• Y direction: ..._POS[1]
• Z direction: ..._POS[2]
Rotation
The rotation is described by the RPY angles A, B and C (RPY stands for Roll Pitch Yaw).
The positive direction of rotation is defined by the right hand rule, i.e. if the thumb on the right
hand is pointing in the direction of the axis of rotation, then the fingers are pointing in the
positive angular direction. In this respect, it must be noted that A and C are defined at
intervals [-180; +180] and B at intervals [-90; +90].
The definitions of the RPY angles are as follows:
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Special functions: Handling Transformation Package (TE4)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0