Absolute data input
Setting of G90 or G91 allows succeeding dimensional data to be processed as absolute data or incremental data. Setting of arc radius (with address R) or arc center position (with addresses I, J, K) for circular interpolation, however, must always refer to incremental data input, irrespective of preceding G90 command. Inch command/metric command selection is possible with G-code commands.
G90 is modal (group 03) — it stays in effect until another code of the same group replaces it.
Initial state: a parameter can select G90 as the initial modal condition — what your machine wakes up in depends on that setting.
G90 (or G91) Xx Yy Zz 1 ( : Additional axis)
- where G90: Absolute data input
- G91: Incremental data input
- G20: Inch command selection
- G21: Metric command selection
- Do not fail to give an F command appropriate to the new unit system after
Mazak PROGRAMMING MANUAL for EIA/ISO PROGRAM, manual H747PB0030E, section 5-1-1 Absolute/Incremental data input: G90/G91, p. 3-11, 5-1, 5-2, 5-3. Reference and explanation only — not a reproduction of the manual.