Siemens SINUMERIK 840Di sl Programming Manual page 26

Fundamental Geometrical Principles
1.3 Position of coordinate systems
Right-hand rule
The orientation of the coordinate system relative to the machine depends on the machine
type. The axis directions follow the so-called "three-finger rule" of the right hand (in
accordance with DIN 66217).
Seen from in front of the machine, the middle finger of the right hand points in the opposite
direction to the infeed of the main spindle. Therefore:
• the thumb points in the +X direction
• the index finger points in the +Y direction
• the middle finger points in the +Z direction
Determination from the right hand rule for different machine types
With different machine types the determination from the right hand rule can look different in
each case. The following are examples of machine coordinate systems for various
machines.
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Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
Fundamentals