GRBL Settings Pocket Guide Rev B

User Manual:

Open the PDF directly: View PDF .
Page Count: 2

Command

$0=10

$1=25

$2=0

Setting Value Reverse X Reverse Y Reverse Z Setting Value Reverse X Reverse Y

0NO NO NO 4NO NO

1YES NO NO 5YES NO

2NO YES NO 6NO YES

3YES YES NO 7YES YES

$3=6

$4=0

$5=0

$6=0

Value

$11=0.020

$12=0.002

$13=0

$20=0

$21=0

$22=0

$23=1

This refers to the probe pins which by default are set to high using the Arduino's internal

pull up resistors. Grounding the pin tells GRBL the probe is tripped. For the opposite

behavior use the setting $6=1 which tells the system that a high is the probe trigger. You

must also install external pull down resistor with the $6=1 setting.

Think of this as cornering speed. A high values allows for fast motion around corners but

increases the risk of missed steps resulting in decreased accuracy. Conversely, lower

values reduce the speed around a corner decreasing the risk of missing steps while

potentially improving accuracy.

GRBL treats curves as a collection of small straight lines. This setting defines how smooth

the curves will be. The default is .002mm and will not likely need to be changed as this

value is below the accuracy of most machines.

YES

DIY Machining - GRBL Settings - Pocket Guide

The following settings are specific to GRBL v0.9 - For more information visit www.DiyMachining.com/GRBL

Explanation

Displays current GRBL settings stored in EEPROM (memory) of the Arduino

Step Pulse Configuration

Axis Direction

Step Enable Invert

Limit Pins Invert

Probe Pin Invert

Definition

View Settings

Step Pulse Length (µsec)

Step Idle Delay (msec)

Axis

Config.

Table

$10=3

Status Report

Junction Deviation (mm)

Arc Tolerance (mm)

This sets the length of the step pulse delivered to the stepper motors. The goal is to have

the shortest step pulse your motors can reliably recognize. The data is available on some

stepper motor data sheets otherwise 10 is a good default.

Sets the time delay in milliseconds that GRBL will power the stepper motors after a

motion command is complete. A setting of 255 tells the motors to stay powered on to

hold position.

Defines the step signal sent to the stepper motor drivers. By default the step signal starts

low and goes high to denote a step pulse event. See Axis Config. Table below.

Changes axis motion direction without changing wiring. See Axis Config. Table above.

Controls the signal sent to the enable pin of your stepper drivers. $4=1 sets the enable

pin to high. (Invert)

This refers to the limit switch pins which by default are set to high using the Arduino's

internal pull up resistors. Grounding the pin tells GRBL the limit switch is tripped. For the

opposite behavior use the setting $5=1 which tells the system that a high is the limit

switch trigger. You must also install external pull down resistor with the $5=1 setting.

Reverse Z

YES

Allows the user to change the direction of the homing cycle us the values from the Axis

Config. Table on page 1.

Feedback Units

Soft Limits (Enable/Disable)

Hard Limits (Enable/Disable)

Homing Cycle

(Enable/Disable)

Homing Cycle Direction

Defines the real time data sent to the user. By default

GRBL reports running state which cannot be turned off,

machine position & work position. The table to the right

details the settings. Note to send a combination of status

reports, simply add the values of the desired report types

and send this value to GRBL. For Example, say I want Work

Position (2) & Limits (16), I would send $10=18.

Report Type

Machine Position

Work Position

Planner Buffer

Sets position feedback units from mm to inches. $13=1 for inches or $13=0 for mm

Requires "Homing" be enabled and checks to see if gCode commands will exceed the

travel limits of the machine. $20=1 Enable $20=0 Disable

Requires limit switches be installed and looks for one of the limit switches to be

activated which triggers "Alarm" mode. In this mode, all machine motion, the spindle

and coolant are shutdown.

Requires limit switches be installed. Enabling this will lock out all gCode commands until

a "Homing" cycle is run.

RX Buffer

Limit Pins

For more information visit www.DIYMachining.com/GRBL

Command

Explanation

Definition

$24=50.000

$25=635.000

$26=250

$27=1.000

$100=314.961

$101=314.961

$102=314.961

$110=635.000

$111=635.000

$112=635.000

$120=50.000

$121=50.000

$122=50.000

$130=225.000

$131=125.000

$132=170.000

$N0=line

$N1=line

$x=value

ctrl-x

Feed rate used in the "Homing" cycle once the limit switches are located. The lower the

value the more repeatable the zero position.

Z - Max Acceleration

(mm/sec2)

X - Max Travel (mm)

Y - Max Travel (mm)

Y (steps/mm)

Z (steps/mm)

X - Max Rate (mm/min)

Y - Max Rate (mm/min)

X - Max Acceleration

(mm/sec2)

Y - Max Acceleration

(mm/sec2)

Homing Feed (mm/min)

Homing Seek (mm/min)

Homing Debounce (msec)

Homing Pull-off (mm)

X (steps/mm)

Save GRBL Setting

Save Startup Block

Check gCode Mode

Z - Max Travel (mm)

Z - Max Rate (mm/min)

View gCode Parameter

View Parser State

View Build Info

Tells the machine how far to move away from the limit switches after finding the "Home"

position so as not to trigger the hard limits.

Tells GRBL how many steps are required to move the machine a given distance.

Steps/mm = (Steps per Revolution)*(Microsteps) / (mm per Revolution)

1) Steps per Revolution = 200 Typical - This is the number of steps required

for your stepper motor to make 1 complete revolution.

2) Microsteps - 1,2,4,8,16 - Is a setting on your stepper motor driver. A higher

value means lower torque but higher accuracy.

3) mm per Revolution - Determined by your machine setup. (lead screw pitch)

Defines the maximum speed for a given axis. This is found experimentally for each axis by

incrementally increasing the value and then sending a test gCode command to move the

axis. Be sure the command allows the axis to move enough to reach the maximum rate.

You will know the maximum speed when the stepper motors stalls. Reduce the value by

10-20% These values may be different for each axis.

Defines the maximum acceleration for a given axis. This is found experimentally for each

axis by incrementally increasing the value and then sending a test gCode command to

move the axis. Be sure the command allows the axis to move enough to reach constant

motion. If you decide to use a jog command make sure the jog increment is several

inches. You will know the maximum value when the stepper motors stalls. Reduce the

value by 10-20% These values may be different for each axis.

Used when soft limits are enable to tell GRBL the maximum travel for each axis. This also

requires the use of a homing cycle.

Feed rate used in the "Homing" cycle to locate the limit switches. Set this to the highest

value that does not cause the machine to crash into the limit switches.

Length of the software delay in milliseconds that minimizes switch noise. A value

between 5 an 25 is typical.

Starts buffered gCode commands. Used to resume cutting after a "Feed Hold."

Stops active cycle by controlled deceleration preventing position lose from missed steps.

Returns the active GRBL state & current machine & work positions.

Soft reset command retains machine position without powering down the Arduino.

GRBL Commands

Real Time GRBL Commands

Displays the startup blocks run each time GRBL is powered on or reset.

Command used to save a GRBL setting. Replace the "X" with a number from the list

above and the "value" with the corresponding setting.

Command used to save startup blocks. Substitute valid gCode commands for the "line"

portion and these will executed each time GRBL is powered on or reset.

Processes all incoming gCode commands but does not move the axis, spindle or coolant

so the user can check a gCode program.

Overrides the alarm lock to allow for axis movement.

Executes the homing cycle.

Cycle Start

Feed Hold

Current Status

Reset GRBL

Kill Alarm Lock

Run Homing Cycle

Lists work coordinate offsets (G54-G59), Predefined positions (G28 & G30), Coordinate

offset (G92), Tool Length Offset (TLO) & Probing cycle (PRB).

Displays the active gCode modes in the GRBL parser.

Example - [G0 G54 G17 G21 G90 G94 M0 M5 M9 T0 S0.0 F500.0]

Shows the GRBL version and source code build date.

View Startup Blocks

For more information visit www.DIYMachining.com/GRBL

GRBL Settings Pocket Guide Rev B

Navigation menu

Versions of this User Manual:

Views

Navigation