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1.2.3 Definition of Travels and Origins
The NC processor computes all movements with respect to the measurement origin or zero point of the machine.
When the system is turned on, it does not know the measurement origin. The mechanical travel on each machine axis
is limited by maximum and minimum limit switches.
OM :
The system establishes the measurement origin (OM) via a homing procedure (MOS).
Om :
The home switch is set in a specific physical location: the machine zero point (Om) may or may not be the
same as the measurement origin (OM).
The homing procedure is completed for each of the axes when:
- the origin limit switch is actuated in the direction of movement specified by the m/c manufacturer (MOS direction),
- the encoder which measures axis movement outputs its marker pulse.
MOS direction
Om
Min. limit
switch
Max. limit
switch
Contact closed Contact open
One encoder revolution
Encoder marker pulse