1.9 L-A4 Default GRBL Parameters

This table lists the default GRBL parameters of the YUMI L-A4.

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1.9.1 Stepper Settings

Code	Parameter	Default	Unit	Description
$0	Step pulse time	10	µs	Duration of a step pulse. Min 3 µs.
$1	Step idle delay	5	ms	Short hold before disabling motors (255 = always enabled).
$2	Step pulse invert	0	mask	Invert STEP signal. Set axis bit (00000ZYX).
$3	Step direction invert	0	mask	Invert DIR signal. Set axis bit (00000ZYX).
$4	Invert step enable pin	0	boolean	Inverts the stepper driver enable pin logic level.
$5	Invert limit pins	0	boolean	Inverts all limit switch inputs.
$6	Invert probe pin	0	boolean	Inverts the probe input.

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1.9.2 Status / Tolerances

Code	Parameter	Default	Unit	Description
$10	Status report options	1	mask	Selects which fields are included in status reports.
$11	Junction deviation	0.010	mm	Cornering tolerance (smaller = smoother/slower).
$12	Arc tolerance	0.002	mm	G2/G3 arc tracing radial error tolerance.
$13	Report in inches	0	boolean	Report positions in inches when enabled.

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1.9.3 Limits / Homing

Code	Parameter	Default	Unit	Description
$20	Soft limits enable	0	boolean	Enable software limits (requires homing).
$21	Hard limits enable	1	boolean	Enable hardware limits (immediate stop on trigger).
$22	Homing cycle enable	1	boolean	Enable homing sequence.
$23	Homing direction invert	3	mask	Invert homing search direction per axis (00000ZYX).
$24	Homing locate feed rate	300	mm/min	Slow feed for precise switch contact.
$25	Homing search seek rate	3000	mm/min	Fast seek to find the limit switch.
$26	Homing switch debounce delay	250	ms	Debounce delay between homing phases.
$27	Homing switch pull-off distance	1	mm	Retract distance after switch triggers.

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1.9.4 Spindle / Laser

Code	Parameter	Default	Unit	Description
$28	—	1000	—	Reserved / firmware-specific.
$30	Maximum spindle speed	1000	RPM	Max spindle speed (PWM = 100%).
$31	Minimum spindle speed	0	RPM	Min spindle speed (PWM ~0.4% or lowest).
$32	Laser-mode enable	1	boolean	No dwell between G1/G2/G3 when S changes.
$37	—	1	—	Reserved / firmware-specific.
$38	—	1	—	Reserved / firmware-specific.
$40	—	1	—	Reserved / firmware-specific.

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1.9.5 Axis Travel Resolution

Code	Parameter	Default	Unit	Description
$100	X-axis travel resolution	80	steps/mm	Steps per millimeter on X.
$101	Y-axis travel resolution	80	steps/mm	Steps per millimeter on Y.
$102	Z-axis travel resolution	80	steps/mm	Steps per millimeter on Z.
$103	A-axis travel resolution	100	steps/mm	Steps per millimeter on A.
$104	B-axis travel resolution	100	steps/mm	Steps per millimeter on B.
$105	C-axis travel resolution	100	steps/mm	Steps per millimeter on C.

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1.9.6 Maximum Rate

Code	Parameter	Default	Unit	Description
$110	X-axis maximum rate	6000	mm/min	Maximum rapid (G0) on X.
$111	Y-axis maximum rate	6000	mm/min	Maximum rapid (G0) on Y.
$112	Z-axis maximum rate	6000	mm/min	Maximum rapid (G0) on Z.
$113	A-axis maximum rate	1000	mm/min	Maximum rapid (G0) on A.
$114	B-axis maximum rate	1000	mm/min	Maximum rapid (G0) on B.
$115	C-axis maximum rate	1000	mm/min	Maximum rapid (G0) on C.

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1.9.7 Acceleration

Code	Parameter	Default	Unit	Description
$120	X-axis acceleration	500	mm/sec²	Planner acceleration for X.
$121	Y-axis acceleration	500	mm/sec²	Planner acceleration for Y.
$122	Z-axis acceleration	500	mm/sec²	Planner acceleration for Z.
$123	A-axis acceleration	200	mm/sec²	Planner acceleration for A.
$124	B-axis acceleration	200	mm/sec²	Planner acceleration for B.
$125	C-axis acceleration	200	mm/sec²	Planner acceleration for C.

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1.9.8 Maximum Travel

Code	Parameter	Default	Unit	Description
$130	X-axis maximum travel	210	mm	Usable X travel (soft-limits & homing).
$131	Y-axis maximum travel	297	mm	Usable Y travel (soft-limits & homing).
$132	Z-axis maximum travel	80	mm	Usable Z travel (soft-limits & homing).
$133	A-axis maximum travel	300	mm	Usable A travel.
$134	B-axis maximum travel	300	mm	Usable B travel.
$135	C-axis maximum travel	300	mm	Usable C travel.