Grbl has a set of configurable machine settings that define how your CNC controller operates. You can view and edit these settings by sending $$ over the serial interface. Each setting is identified with a $ followed by a number, like $0, $100, etc.
Below is a full list of Grbl v1.1 settings with explanations of what each setting controls.
Motion Settings
| Setting | Description |
$0 |
Step pulse time – Sets the duration of the step pulse sent to the stepper driver. |
$1 |
Step idle delay – Sets the delay before the motors are disabled after motion is complete. |
$2 |
Step pulse invert – Inverts the direction of the step pulses if needed by your driver. |
$3 |
Direction port invert – Reverses the direction of motion for individual axes. |
$4 |
Step enable invert – Inverts the enable signal sent to motor drivers. |
$5 |
Limit pins invert – Inverts the logic level for limit switches. |
$6 |
Probe pin invert – Inverts the logic level for the probe pin. |
Status Report and Units
| Setting | Description |
$10 |
Status report mask – Controls what information is shown in the status report (? command). |
$11 |
Junction deviation – Controls the cornering speed between path segments. |
$12 |
Arc tolerance – Defines the accuracy of arc generation. |
$13 |
Report inches – Enables status reporting in inches instead of millimeters. |
Safety and Limit Features
| Setting | Description |
$20 |
Soft limits enable – Enables software-enforced travel limits. |
$21 |
Hard limits enable – Enables physical limit switch enforcement. |
$22 |
Homing cycle enable – Enables the homing cycle using limit switches. |
$23 |
Homing direction invert – Controls homing direction for each axis. |
$24 |
Homing locate feed rate – Speed of the final homing move toward the switch. |
$25 |
Homing search seek rate – Speed of the initial homing move. |
$26 |
Homing switch debounce delay – Debounce time to filter out switch noise. |
$27 |
Homing switch pull-off distance – Distance to back off the switch after triggering. |
Spindle & Laser Control
| Setting | Description |
$30 |
Maximum spindle speed – Sets the max spindle RPM corresponding to full PWM duty cycle. |
$31 |
Minimum spindle speed – Sets the min spindle RPM corresponding to minimum PWM duty. |
$32 |
Laser mode enable – Enables laser mode for smoother laser engraving performance. |
Steps and Travel Calibration
| Setting | Description |
$100 |
X-axis steps/mm – Number of steps required to move the X axis by one millimeter. |
$101 |
Y-axis steps/mm – Number of steps required to move the Y axis by one millimeter. |
$102 |
Z-axis steps/mm – Number of steps required to move the Z axis by one millimeter. |
$110 |
X-axis max rate – Maximum movement speed for the X axis. |
$111 |
Y-axis max rate – Maximum movement speed for the Y axis. |
$112 |
Z-axis max rate – Maximum movement speed for the Z axis. |
$120 |
X-axis acceleration – Acceleration value for the X axis. |
$121 |
Y-axis acceleration – Acceleration value for the Y axis. |
$122 |
Z-axis acceleration – Acceleration value for the Z axis. |
$130 |
X-axis max travel – Maximum travel distance allowed on the X axis. |
$131 |
Y-axis max travel – Maximum travel distance allowed on the Y axis. |
$132 |
Z-axis max travel – Maximum travel distance allowed on the Z axis. |
Notes:
-
To change a setting, send a command like
$21=0via the Easel Machine Inspector. -
Use
$$to view all current settings. -
Always double-check units and values to avoid unexpected machine behavior.