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M78 Alarm if skip signal found
Haas NGC M-code · Mill, Lathe
On mills: Alarm if skip signal found
Used after a G31 move. Alarms if the probe skip signal was found when it should not have been.
Format
M78
How it works
Not modal. Acts once on the line where it is commanded.
Example program
G90 G54 G00 X-1. Y0. (CLEAR OF THE PART)
G31 X1. F10. (PROBE MOVE THAT SHOULD NOT TOUCH)
M78 (ALARM IF THE PROBE TRIPPED)
G31 X1. F10. (PROBE MOVE THAT SHOULD NOT TOUCH)
M78 (ALARM IF THE PROBE TRIPPED)
Example is in inch. Check offsets and clearances first.
Watch out for
- Use it to check that a move did not touch anything.
On lathes: Alarm if skip signal found
Alarms if the last G31 move received a probe signal. Use when no contact is expected, so a hit means a crash or a wrong setup.
Format
M78
How it works
Non-modal.
Example program
G31 Z-.5 F10. (MOVE, NO CONTACT EXPECTED)
M78 (ALARM IF PROBE HIT SOMETHING)
G00 Z.5 (RETRACT)
M78 (ALARM IF PROBE HIT SOMETHING)
G00 Z.5 (RETRACT)
Example is in inch. Check offsets and clearances first.
Watch out for
- Put it on the G31 line or any block after.
Related codes
M78 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Doosan (Fanuc) | Tail stock quill advance |
| Okuma OSP | Steady rest unclamp |
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