HEIDENHAIN TNC 620, User Manual

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Testing and running | Miscellaneous functions for coordinate entries
6.17 Miscellaneous functions for coordinate
entries
Programming machine-referenced coordinates: M91/
M92
Scale datum
On the scale, a reference mark indicates the position of the scale
datum.
Machine datum
The machine datum is required for the following tasks:
Define the axis traverse limits (software limit switches)
Approach machine-referenced positions (such as tool change
positions)
Set a workpiece preset
The distance in each axis from the scale datum to the machine
datum is defined by the machine tool builder in a machine
parameter.
Standard behavior
The control references the coordinates to the workpiece datum.
Further information: "Presetting without a 3D touch probe",
Page 201
Behavior with M91—Machine datum
If you want the coordinates in a positioning block to be referenced to
the machine datum, enter M91 into these NC blocks.
If you program incremental coordinates in an NC block
with the miscellaneous function
M91
, then these
coordinates are relative to the last position programmed
with
M91
. If the active NC program does not contain
a position programmed with
M91
, the coordinates
reference the current tool position.
The coordinate values on the control's screen are referenced to
the machine datum. Switch the display of coordinates in the status
display to REF.
Further information: "Status displays", Page 68
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HEIDENHAIN | TNC 620 | User's Manual for Setup, Testing and Running NC Programs | 01/2022
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