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G74 Reference point approach
Siemens 840D 828D G-code · Mill and lathe
Moves the listed machine axes to their reference point from the program. Used after a power up on machines with incremental encoders or before a measuring routine.
Format
G74 X1=0 Y1=0 Z1=0
Addresses
| Address | What it does |
|---|---|
X1= Y1= Z1= | Machine axis names to reference. The value is not used but must be written. |
How it works
Non modal. Must be in its own block.
Example program
G0 Z50 ; CLEAR THE PART
G74 Z1=0 ; Z TO REFERENCE POINT FIRST
G74 X1=0 Y1=0 ; THEN X AND Y
G74 Z1=0 ; Z TO REFERENCE POINT FIRST
G74 X1=0 Y1=0 ; THEN X AND Y
Example is in inch. Check offsets and clearances first.
Watch out for
- Axis names like X1 and Z1 are machine axis names set by the machine builder, not the work axis names.
- Turn off transformations such as TRAORI before G74.
Related codes
G74 on other controls
The same number can mean something different on another control.
| Control | Meaning |
|---|---|
| Fanuc | Left hand tapping cycle |
| Haas NGC | Reverse tapping cycle |
| Mazak (EIA) | Reverse tapping cycle |
| Okuma OSP | Reverse tapping cycle |
| Mitsubishi M70 M80 | Reverse tapping cycle |
| Brother Speedio | Left hand tapping cycle |
| Fagor 8055 8065 | Home search |
| LinuxCNC Tormach | Left hand tapping cycle |
| Mach3 Mach4 | Left hand tapping, Mach4 |
| Centroid CNC12 Acorn | Left hand tapping cycle |
| Hurco WinMax (NC) | Left hand tap (ISNC) or single quadrant arc (BNC) |
| Fadal | Left hand tap |
| Swiss (Citizen Star) | Face peck drilling and grooving cycle |
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