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M91 Coordinates in machine datum
Heidenhain TNC (ISO) M-code · Mill
In this block the coordinates refer to the machine datum, not the workpiece datum. Klartext: L Z+0 R0 FMAX M91.
Format
G00 G40 Z M91
Addresses
| Address | What it does |
|---|---|
Z | Position in machine coordinates |
How it works
Non-modal. Acts only in its block.
Example program
N150 G00 G40 Z-20 M91 *
N160 X+500 Y+400 M91 *
N170 M30 *
N160 X+500 Y+400 M91 *
N170 M30 *
Example is in inch. Check offsets and clearances first.
Watch out for
- Values depend on the machine. Check the machine datum before using M91 for a safe retract.
- Radius compensation must be off.
Related codes
M91 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Haas NGC | Fixture clamp input off |
| Doosan (Fanuc) | External m-code m91 |
| DMG Mori MAPPS (Fanuc) | Tool-spindle or turning spindle simultaneous operation mode OFF |
| Centroid CNC12 Acorn | Move to minus home switch |
| Hurco WinMax (NC) | Z retract on power loss, disable |
| Fadal | Normal servo gain |
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