Reference point return

Q: What does Mazak G-code G28 do?

G28 — Reference point return on the MAZATROL SmoothX control (INTEGREX e-670H).  Use a G28 command to perform return to the first reference point (zero point) after rapid positioning (in G00 mode) to the desired intermediate point along the specified axes.  Use a G29 command to perform rapid positioning (in G00 mode) through the intermediate point (of the preceding G28 or G30 command) to the desired point along the specified axes. Second reference point First reference point Starting point Interm. point Machine zero point Starting point The returning to the second, third, or fourth reference point can be programmed by setting “G30 Second reference point First reference point Starting point Interm. point Third reference point Fourth reference point

Q: What is the programming format of G28?

G28 Xx Yy Zz 1 ; (: Additional axis) Automatic return to reference point G29 Xx Yy Zz 2 ; (: Additional axis) Return to start point G30 P2 (P3, P4) Xx Yy Zz 1 ; (: Addition axis.)

Machine-specific. This G-code reference is specific to the Mazak INTEGREX e-670H / e-670H-S with the MAZATROL SmoothX control (EIA/ISO programming manual H747PB0030E). G-code availability depends on fitted options, and groups and behaviour differ between Mazak models and control generations — verify against the manual for your own machine before programming with any code.

What it does

 Use a G28 command to perform return to the first reference point (zero point) after rapid positioning (in G00 mode) to the desired intermediate point along the specified axes.  Use a G29 command to perform rapid positioning (in G00 mode) through the intermediate point (of the preceding G28 or G30 command) to the desired point along the specified axes. Second reference point First reference point Starting point Interm. point Machine zero point Starting point The returning to the second, third, or fourth reference point can be programmed by setting “G30 Second reference point First reference point Starting point Interm. point Third reference point Fourth reference point

G28 is one-shot (group 00) — it is valid only in the block where it is entered.

Programming format

G28 Xx
Yy
Zz
1 ; (: Additional axis) Automatic return to reference point
G29 Xx
Yy
Zz
2 ; (: Additional axis) Return to start point
G30 P2 (P3, P4) Xx
Yy
Zz
1 ; (: Addition axis.)

Source

Mazak PROGRAMMING MANUAL for EIA/ISO PROGRAM, manual H747PB0030E, section 14-10 Automatic Return to Reference Point (Zero Point): G28, G29, p. 3-11, 14-25, 14-26, 14-27, 14-28. Reference and explanation only — not a reproduction of the manual.

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