Absolute Programming (G90)

Definition

Coordinate values are referenced to the zero point. Use it when dimensions are referenced from the active work offset instead of the last point.

Formula / Rule

• G90 means each commanded X, Y, and Z value is interpreted from the active datum such as G54.
• Reissue G90 after macros, subprograms, or transferred code if positioning state is uncertain.

Typical Range

• Best for setup-critical moves, restarts, and dimension-driven verification.

Shop-floor Scenarios

• Restart after a tool change with G90 in the safety line before moving near the part.
• Use it when inspection values are reported directly against the work offset.

Common Errors / Troubleshooting

• If the tool jumps after restart, confirm whether G91 was left active earlier.
• If size error repeats, verify work offset and probing results before editing coordinates.

Related Tools

• G/M Code Reference
• G-code Viewer