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M79 Alarm if skip signal not found
Haas NGC M-code · Mill, Lathe
On mills: Alarm if skip signal not found
Used after a G31 move. Alarms if the probe skip signal was not found, which means the probe missed the part.
Format
M79
How it works
Not modal. Acts once on the line where it is commanded.
Example program
G90 G54 G00 X-1. Y0. (LEFT OF THE PART)
G31 X0. F10. (PROBE TOWARD THE PART)
M79 (ALARM IF THE PROBE DID NOT TRIP)
G31 X0. F10. (PROBE TOWARD THE PART)
M79 (ALARM IF THE PROBE DID NOT TRIP)
Example is in inch. Check offsets and clearances first.
Watch out for
- Always follow a probe G31 with M79 so a missing part stops the program.
On lathes: Alarm if skip signal not found
Alarms if the last G31 move did not receive a probe signal. Use when contact is expected, so no hit means a missing part or bad position.
Format
M79
How it works
Non-modal.
Example program
G31 Z-1. F10. (PROBE THE FACE)
M79 (ALARM IF NO CONTACT)
G00 Z.5 (RETRACT)
M79 (ALARM IF NO CONTACT)
G00 Z.5 (RETRACT)
Example is in inch. Check offsets and clearances first.
Watch out for
- Use M79 after every probing move that should touch.
Related codes
M79 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Doosan (Fanuc) | Tail stock quill retract |
| Okuma OSP | Steady rest clamp |
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