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Sergunb
Date:
Mon Sep 04 12:04:13 2017 +0000
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Sergunb 0:8f0d870509fe 1 # Grbl v1.1 Commands
Sergunb 0:8f0d870509fe 2
Sergunb 0:8f0d870509fe 3 In general, Grbl assumes all characters and streaming data sent to it is g-code and will parse and try to execute it as soon as it can. However, Grbl also has two separate system command types that are outside of the normal g-code streaming. One system command type is streamed to Grbl like g-code, but starts with a `$` character to tell Grbl it's not g-code. The other is composed of a special set of characters that will immediately command Grbl to do a task in real-time. It's not part of the g-code stream. Grbl's system commands do things like control machine state, report saved parameters or what Grbl is doing, save or print machine settings, run a homing cycle, or make the machine move faster or slower than programmed. This document describes these "internal" system Grbl commands, what they do, how they work, and how to use them.
Sergunb 0:8f0d870509fe 4
Sergunb 0:8f0d870509fe 5 ## Getting Started
Sergunb 0:8f0d870509fe 6
Sergunb 0:8f0d870509fe 7 First, connect to Grbl using the serial terminal of your choice.
Sergunb 0:8f0d870509fe 8
Sergunb 0:8f0d870509fe 9 Set the baud rate to **115200** as 8-N-1 (8-bits, no parity, and 1-stop bit.)
Sergunb 0:8f0d870509fe 10
Sergunb 0:8f0d870509fe 11 Once connected
Sergunb 0:8f0d870509fe 12 you should get the Grbl-prompt, which looks like this:
Sergunb 0:8f0d870509fe 13
Sergunb 0:8f0d870509fe 14 ```
Sergunb 0:8f0d870509fe 15 Grbl 1.1e ['$' for help]
Sergunb 0:8f0d870509fe 16 ```
Sergunb 0:8f0d870509fe 17
Sergunb 0:8f0d870509fe 18 Type $ and press enter to have Grbl print a help message. You should not see any local echo of the $ and enter. Grbl should respond with:
Sergunb 0:8f0d870509fe 19
Sergunb 0:8f0d870509fe 20 ```
Sergunb 0:8f0d870509fe 21 [HLP:$$ $# $G $I $N $x=val $Nx=line $J=line $SLP $C $X $H ~ ! ? ctrl-x]
Sergunb 0:8f0d870509fe 22 ```
Sergunb 0:8f0d870509fe 23
Sergunb 0:8f0d870509fe 24 The ‘$’-commands are Grbl system commands used to tweak the settings, view or change Grbl's states and running modes, and start a homing cycle. The last four **non**-'$' commands are realtime control commands that can be sent at anytime, no matter what Grbl is doing. These either immediately change Grbl's running behavior or immediately print a report of the important realtime data like current position (aka DRO). There are over a dozen more realtime control commands, but they are not user type-able. See realtime command section for details.
Sergunb 0:8f0d870509fe 25
Sergunb 0:8f0d870509fe 26 ***
Sergunb 0:8f0d870509fe 27
Sergunb 0:8f0d870509fe 28 ## Grbl '$' Commands
Sergunb 0:8f0d870509fe 29
Sergunb 0:8f0d870509fe 30 The `$` system commands provide additional controls for the user, such as printing feedback on the current G-code parser modal state or running the homing cycle. This section explains what these commands are and how to use them.
Sergunb 0:8f0d870509fe 31
Sergunb 0:8f0d870509fe 32 #### `$$`and `$x=val` - View and write Grbl settings
Sergunb 0:8f0d870509fe 33 See [Grbl v1.1 Configuration](https://github.com/gnea/grbl/wiki/Grbl-v1.1-Configuration#grbl-settings) for more details on how to view and write setting and learn what they are.
Sergunb 0:8f0d870509fe 34
Sergunb 0:8f0d870509fe 35 #### `$#` - View gcode parameters
Sergunb 0:8f0d870509fe 36
Sergunb 0:8f0d870509fe 37 G-code parameters store the coordinate offset values for G54-G59 work coordinates, G28/G30 pre-defined positions, G92 coordinate offset, tool length offsets, and probing (not officially, but we added here anyway). Most of these parameters are directly written to EEPROM anytime they are changed and are persistent. Meaning that they will remain the same, regardless of power-down, until they are explicitly changed. The non-persistent parameters, which will are not retained when reset or power-cycled, are G92, G43.1 tool length offsets, and the G38.2 probing data.
Sergunb 0:8f0d870509fe 38
Sergunb 0:8f0d870509fe 39 G54-G59 work coordinates can be changed via the `G10 L2 Px` or `G10 L20 Px` command defined by the NIST gcode standard and the EMC2 (linuxcnc.org) standard. G28/G30 pre-defined positions can be changed via the `G28.1` and the `G30.1` commands, respectively.
Sergunb 0:8f0d870509fe 40
Sergunb 0:8f0d870509fe 41 When `$#` is called, Grbl will respond with the stored offsets from machine coordinates for each system as follows. `TLO` denotes tool length offset (for the default z-axis), and `PRB` denotes the coordinates of the last probing cycle, where the suffix `:1` denotes if the last probe was successful and `:0` as not successful.
Sergunb 0:8f0d870509fe 42
Sergunb 0:8f0d870509fe 43 ```
Sergunb 0:8f0d870509fe 44 [G54:4.000,0.000,0.000]
Sergunb 0:8f0d870509fe 45 [G55:4.000,6.000,7.000]
Sergunb 0:8f0d870509fe 46 [G56:0.000,0.000,0.000]
Sergunb 0:8f0d870509fe 47 [G57:0.000,0.000,0.000]
Sergunb 0:8f0d870509fe 48 [G58:0.000,0.000,0.000]
Sergunb 0:8f0d870509fe 49 [G59:0.000,0.000,0.000]
Sergunb 0:8f0d870509fe 50 [G28:1.000,2.000,0.000]
Sergunb 0:8f0d870509fe 51 [G30:4.000,6.000,0.000]
Sergunb 0:8f0d870509fe 52 [G92:0.000,0.000,0.000]
Sergunb 0:8f0d870509fe 53 [TLO:0.000]
Sergunb 0:8f0d870509fe 54 [PRB:0.000,0.000,0.000:0]
Sergunb 0:8f0d870509fe 55 ```
Sergunb 0:8f0d870509fe 56
Sergunb 0:8f0d870509fe 57 #### `$G` - View gcode parser state
Sergunb 0:8f0d870509fe 58
Sergunb 0:8f0d870509fe 59 This command prints all of the active gcode modes in Grbl's G-code parser. When sending this command to Grbl, it will reply with a message starting with an `[GC:` indicator like:
Sergunb 0:8f0d870509fe 60
Sergunb 0:8f0d870509fe 61 ```
Sergunb 0:8f0d870509fe 62 [GC:G0 G54 G17 G21 G90 G94 M0 M5 M9 T0 S0.0 F500.0]
Sergunb 0:8f0d870509fe 63 ```
Sergunb 0:8f0d870509fe 64
Sergunb 0:8f0d870509fe 65 These active modes determine how the next G-code block or command will be interpreted by Grbl's G-code parser. For those new to G-code and CNC machining, modes sets the parser into a particular state so you don't have to constantly tell the parser how to parse it. These modes are organized into sets called "modal groups" that cannot be logically active at the same time. For example, the units modal group sets whether your G-code program is interpreted in inches or in millimeters.
Sergunb 0:8f0d870509fe 66
Sergunb 0:8f0d870509fe 67 A short list of the modal groups, supported by Grbl, is shown below, but more complete and detailed descriptions can be found at LinuxCNC's [website](http://www.linuxcnc.org/docs/2.4/html/gcode_overview.html#sec:Modal-Groups). The G-code commands in **bold** indicate the default modes upon powering-up Grbl or resetting it. The commands in _italics_ indicate a special Grbl-only command.
Sergunb 0:8f0d870509fe 68
Sergunb 0:8f0d870509fe 69 | Modal Group Meaning | Member Words |
Sergunb 0:8f0d870509fe 70 |:----:|:----:|
Sergunb 0:8f0d870509fe 71 | Motion Mode | **G0**, G1, G2, G3, G38.2, G38.3, G38.4, G38.5, G80 |
Sergunb 0:8f0d870509fe 72 |Coordinate System Select | **G54**, G55, G56, G57, G58, G59|
Sergunb 0:8f0d870509fe 73 |Plane Select | **G17**, G18, G19|
Sergunb 0:8f0d870509fe 74 |Distance Mode | **G90**, G91|
Sergunb 0:8f0d870509fe 75 |Arc IJK Distance Mode | **G91.1** |
Sergunb 0:8f0d870509fe 76 |Feed Rate Mode | G93, **G94**|
Sergunb 0:8f0d870509fe 77 |Units Mode | G20, **G21**|
Sergunb 0:8f0d870509fe 78 |Cutter Radius Compensation | **G40** |
Sergunb 0:8f0d870509fe 79 |Tool Length Offset |G43.1, **G49**|
Sergunb 0:8f0d870509fe 80 |Program Mode | **M0**, M1, M2, M30|
Sergunb 0:8f0d870509fe 81 |Spindle State |M3, M4, **M5**|
Sergunb 0:8f0d870509fe 82 |Coolant State | M7, M8, **M9** |
Sergunb 0:8f0d870509fe 83 |Override Control | _M56_ |
Sergunb 0:8f0d870509fe 84
Sergunb 0:8f0d870509fe 85 Grbl supports a special _M56_ override control command, where this enables and disables Grbl's parking motion when a `P1` or a `P0` is passed with `M56`, respectively. This command is only available when both parking and this particular option is enabled.
Sergunb 0:8f0d870509fe 86
Sergunb 0:8f0d870509fe 87 In addition to the G-code parser modes, Grbl will report the active `T` tool number, `S` spindle speed, and `F` feed rate, which all default to 0 upon a reset. For those that are curious, these don't quite fit into nice modal groups, but are just as important for determining the parser state.
Sergunb 0:8f0d870509fe 88
Sergunb 0:8f0d870509fe 89 #### `$I` - View build info
Sergunb 0:8f0d870509fe 90 This prints feedback to the user the Grbl version and source code build date. Optionally, `$I` can also store a short string to help identify which CNC machine you are communicating with, if you have more than machine using Grbl. To set this string, send Grbl `$I=xxx`, where `xxx` is your customization string that is less than 80 characters. The next time you query Grbl with a `$I` view build info, Grbl will print this string after the version and build date.
Sergunb 0:8f0d870509fe 91
Sergunb 0:8f0d870509fe 92 NOTE: Some OEMs may block access to over-writing the build info string so they can store product information and codes there.
Sergunb 0:8f0d870509fe 93
Sergunb 0:8f0d870509fe 94 #### $N - View startup blocks
Sergunb 0:8f0d870509fe 95
Sergunb 0:8f0d870509fe 96 `$Nx` are the startup blocks that Grbl runs every time you power on Grbl or reset Grbl. In other words, a startup block is a line of G-code that you can have Grbl auto-magically run to set your G-code modal defaults, or anything else you need Grbl to do everytime you start up your machine. Grbl can store two blocks of G-code as a system default.
Sergunb 0:8f0d870509fe 97
Sergunb 0:8f0d870509fe 98 So, when connected to Grbl, type `$N` and then enter. Grbl should respond with something short like:
Sergunb 0:8f0d870509fe 99 ```
Sergunb 0:8f0d870509fe 100 $N0=
Sergunb 0:8f0d870509fe 101 $N1=
Sergunb 0:8f0d870509fe 102 ok
Sergunb 0:8f0d870509fe 103 ```
Sergunb 0:8f0d870509fe 104 Not much to go on, but this just means that there is no G-code block stored in line `$N0` for Grbl to run upon startup. `$N1` is the next line to be run.
Sergunb 0:8f0d870509fe 105
Sergunb 0:8f0d870509fe 106 #### $Nx=line - Save startup block
Sergunb 0:8f0d870509fe 107
Sergunb 0:8f0d870509fe 108 **IMPORTANT: Be very careful when storing any motion (G0/1,G2/3,G28/30) commands in the startup blocks. These motion commands will run everytime you reset or power up Grbl, so if you have an emergency situation and have to e-stop and reset, a startup block move can and will likely make things worse quickly. Also, do not place any commands that save data to EEPROM, such as G10/G28.1/G30.1. This will cause Grbl to constantly re-write this data upon every startup and reset, which will eventually wear out your Arduino's EEPROM.**
Sergunb 0:8f0d870509fe 109
Sergunb 0:8f0d870509fe 110 **Typical usage for a startup block is simply to set your preferred modal states, such as G20 inches mode, always default to a different work coordinate system, or, to provide a way for a user to run some user-written unique feature that they need for their crazy project.**
Sergunb 0:8f0d870509fe 111
Sergunb 0:8f0d870509fe 112 To set a startup block, type `$N0=` followed by a valid G-code block and an enter. Grbl will run the block to check if it's valid and then reply with an `ok` or an `error:` to tell you if it's successful or something went wrong. If there is an error, Grbl will not save it.
Sergunb 0:8f0d870509fe 113
Sergunb 0:8f0d870509fe 114 For example, say that you want to use your first startup block `$N0` to set your G-code parser modes like G54 work coordinate, G20 inches mode, G17 XY-plane. You would type `$N0=G20 G54 G17` with an enter and you should see an `ok` response. You can then check if it got stored by typing `$N` and you should now see a response like `$N0=G20G54G17`.
Sergunb 0:8f0d870509fe 115
Sergunb 0:8f0d870509fe 116 Once you have a startup block stored in Grbl's EEPROM, everytime you startup or reset you will see your startup block printed back to you, starting with an open-chevron `>`, and a `:ok` response from Grbl to indicate if it ran okay. So for the previous example, you'll see:
Sergunb 0:8f0d870509fe 117
Sergunb 0:8f0d870509fe 118 ```
Sergunb 0:8f0d870509fe 119 Grbl 1.1d ['$' for help]
Sergunb 0:8f0d870509fe 120 >G20G54G17:ok
Sergunb 0:8f0d870509fe 121
Sergunb 0:8f0d870509fe 122 ```
Sergunb 0:8f0d870509fe 123 If you have multiple G-code startup blocks, they will print back to you in order upon every startup. And if you'd like to clear one of the startup blocks, (e.g., block 0) type `$N0=` without anything following the equal sign.
Sergunb 0:8f0d870509fe 124
Sergunb 0:8f0d870509fe 125 NOTE: There are two variations on when startup blocks with run. First, it will not run if Grbl initializes up in an ALARM state or exits an ALARM state via an `$X` unlock for safety reasons. Always address and cancel the ALARM and then finish by a reset, where the startup blocks will run at initialization. Second, if you have homing enabled, the startup blocks will execute immediately after a successful homing cycle, not at startup.
Sergunb 0:8f0d870509fe 126
Sergunb 0:8f0d870509fe 127 #### `$C` - Check gcode mode
Sergunb 0:8f0d870509fe 128 This toggles the Grbl's gcode parser to take all incoming blocks and process them completely, as it would in normal operation, but it does not move any of the axes, ignores dwells, and powers off the spindle and coolant. This is intended as a way to provide the user a way to check how their new G-code program fares with Grbl's parser and monitor for any errors (and checks for soft limit violations, if enabled).
Sergunb 0:8f0d870509fe 129
Sergunb 0:8f0d870509fe 130 When toggled off, Grbl will perform an automatic soft-reset (^X). This is for two purposes. It simplifies the code management a bit. But, it also prevents users from starting a job when their G-code modes are not what they think they are. A system reset always gives the user a fresh, consistent start.
Sergunb 0:8f0d870509fe 131
Sergunb 0:8f0d870509fe 132 #### `$X` - Kill alarm lock
Sergunb 0:8f0d870509fe 133 Grbl's alarm mode is a state when something has gone critically wrong, such as a hard limit or an abort during a cycle, or if Grbl doesn't know its position. By default, if you have homing enabled and power-up the Arduino, Grbl enters the alarm state, because it does not know its position. The alarm mode will lock all G-code commands until the '$H' homing cycle has been performed. Or if a user needs to override the alarm lock to move their axes off their limit switches, for example, '$X' kill alarm lock will override the locks and allow G-code functions to work again.
Sergunb 0:8f0d870509fe 134
Sergunb 0:8f0d870509fe 135 But, tread carefully!! This should only be used in emergency situations. The position has likely been lost, and Grbl may not be where you think it is. So, it's advised to use G91 incremental mode to make short moves. Then, perform a homing cycle or reset immediately afterwards.
Sergunb 0:8f0d870509fe 136
Sergunb 0:8f0d870509fe 137 As noted earlier, startup lines do not execute after a `$X` command. Always reset when you have cleared the alarm and fixed the scenario that caused it. When Grbl resets to idle, the startup lines will then run as normal.
Sergunb 0:8f0d870509fe 138
Sergunb 0:8f0d870509fe 139 #### `$H` - Run homing cycle
Sergunb 0:8f0d870509fe 140 This command is the only way to perform the homing cycle in Grbl. Some other motion controllers designate a special G-code command to run a homing cycle, but this is incorrect according to the G-code standards. Homing is a completely separate command handled by the controller.
Sergunb 0:8f0d870509fe 141
Sergunb 0:8f0d870509fe 142 TIP: After running a homing cycle, rather jogging manually all the time to a position in the middle of your workspace volume. You can set a G28 or G30 pre-defined position to be your post-homing position, closer to where you'll be machining. To set these, you'll first need to jog your machine to where you would want it to move to after homing. Type G28.1 (or G30.1) to have Grbl store that position. So then after '$H' homing, you could just enter 'G28' (or 'G30') and it'll move there auto-magically. In general, I would just move the XY axis to the center and leave the Z-axis up. This ensures that there isn't a chance the tool in the spindle will interfere and that it doesn't catch on anything.
Sergunb 0:8f0d870509fe 143
Sergunb 0:8f0d870509fe 144 #### `$Jx=line` - Run jogging motion
Sergunb 0:8f0d870509fe 145
Sergunb 0:8f0d870509fe 146 New to Grbl v1.1, this command will execute a special jogging motion. There are three main differences between a jogging motion and a motion commanded by a g-code line.
Sergunb 0:8f0d870509fe 147
Sergunb 0:8f0d870509fe 148 - Like normal g-code commands, several jog motions may be queued into the planner buffer, but the jogging can be easily canceled by a jog-cancel or feed-hold real-time command. Grbl will immediately hold the current jog and then automatically purge the buffers of any remaining commands.
Sergunb 0:8f0d870509fe 149 - Jog commands are completely independent of the g-code parser state. It will not change any modes like `G91` incremental distance mode. So, you no longer have to make sure that you change it back to `G90` absolute distance mode afterwards. This helps reduce the chance of starting with the wrong g-code modes enabled.
Sergunb 0:8f0d870509fe 150 - If soft-limits are enabled, any jog command that exceeds a soft-limit will simply return an error. It will not throw an alarm as it would with a normal g-code command. This allows for a much more enjoyable and fluid GUI or joystick interaction.
Sergunb 0:8f0d870509fe 151
Sergunb 0:8f0d870509fe 152 Executing a jog requires a specific command structure, as described below:
Sergunb 0:8f0d870509fe 153
Sergunb 0:8f0d870509fe 154 - The first three characters must be '$J=' to indicate the jog.
Sergunb 0:8f0d870509fe 155 - The jog command follows immediate after the '=' and works like a normal G1 command.
Sergunb 0:8f0d870509fe 156 - Feed rate is only interpreted in G94 units per minute. A prior G93 state is ignored during jog.
Sergunb 0:8f0d870509fe 157 - Required words:
Sergunb 0:8f0d870509fe 158 - XYZ: One or more axis words with target value.
Sergunb 0:8f0d870509fe 159 - F - Feed rate value. NOTE: Each jog requires this value and is not treated as modal.
Sergunb 0:8f0d870509fe 160 - Optional words: Jog executes based on current G20/G21 and G90/G91 g-code parser state. If one of the following optional words is passed, that state is overridden for one command only.
Sergunb 0:8f0d870509fe 161 - G20 or G21 - Inch and millimeter mode
Sergunb 0:8f0d870509fe 162 - G90 or G91 - Absolute and incremental distances
Sergunb 0:8f0d870509fe 163 - G53 - Move in machine coordinates
Sergunb 0:8f0d870509fe 164 - All other g-codes, m-codes, and value words are not accepted in the jog command.
Sergunb 0:8f0d870509fe 165 - Spaces and comments are allowed in the command. These are removed by the pre-parser.
Sergunb 0:8f0d870509fe 166
Sergunb 0:8f0d870509fe 167 - Example: G21 and G90 are active modal states prior to jogging. These are sequential commands.
Sergunb 0:8f0d870509fe 168 - `$J=X10.0 Y-1.5` will move to X=10.0mm and Y=-1.5mm in work coordinate frame (WPos).
Sergunb 0:8f0d870509fe 169 - `$J=G91 G20 X0.5` will move +0.5 inches (12.7mm) to X=22.7mm (WPos). Note that G91 and G20 are only applied to this jog command.
Sergunb 0:8f0d870509fe 170 - `$J=G53 Y5.0` will move the machine to Y=5.0mm in the machine coordinate frame (MPos). If the work coordinate offset for the y-axis is 2.0mm, then Y is 3.0mm in (WPos).
Sergunb 0:8f0d870509fe 171
Sergunb 0:8f0d870509fe 172 Jog commands behave almost identically to normal g-code streaming. Every jog command will
Sergunb 0:8f0d870509fe 173 return an 'ok' when the jogging motion has been parsed and is setup for execution. If a
Sergunb 0:8f0d870509fe 174 command is not valid or exceeds a soft-limit, Grbl will return an 'error:'. Multiple jogging commands may be queued in sequence.
Sergunb 0:8f0d870509fe 175
Sergunb 0:8f0d870509fe 176 NOTE: See additional jogging documentation for details on using this command to create a low-latency joystick or rotary dial interface.
Sergunb 0:8f0d870509fe 177
Sergunb 0:8f0d870509fe 178
Sergunb 0:8f0d870509fe 179 #### `$RST=$`, `$RST=#`, and `$RST=*`- Restore Grbl settings and data to defaults
Sergunb 0:8f0d870509fe 180 These commands are not listed in the main Grbl `$` help message, but are available to allow users to restore parts of or all of Grbl's EEPROM data. Note: Grbl will automatically reset after executing one of these commands to ensure the system is initialized correctly.
Sergunb 0:8f0d870509fe 181
Sergunb 0:8f0d870509fe 182 - `$RST=$` : Erases and restores the `$$` Grbl settings back to defaults, which is defined by the default settings file used when compiling Grbl. Often OEMs will build their Grbl firmwares with their machine-specific recommended settings. This provides users and OEMs a quick way to get back to square-one, if something went awry or if a user wants to start over.
Sergunb 0:8f0d870509fe 183 - `$RST=#` : Erases and zeros all G54-G59 work coordinate offsets and G28/30 positions stored in EEPROM. These are generally the values seen in the `$#` parameters printout. This provides an easy way to clear these without having to do it manually for each set with a `G20 L2/20` or `G28.1/30.1` command.
Sergunb 0:8f0d870509fe 184 - `$RST=*` : This clears and restores all of the EEPROM data used by Grbl. This includes `$$` settings, `$#` parameters, `$N` startup lines, and `$I` build info string. Note that this doesn't wipe the entire EEPROM, only the data areas Grbl uses. To do a complete wipe, please use the Arduino IDE's EEPROM clear example project.
Sergunb 0:8f0d870509fe 185
Sergunb 0:8f0d870509fe 186 NOTE: Some OEMs may restrict some or all of these commands to prevent certain data they use from being wiped.
Sergunb 0:8f0d870509fe 187
Sergunb 0:8f0d870509fe 188 #### `$SLP` - Enable Sleep Mode
Sergunb 0:8f0d870509fe 189
Sergunb 0:8f0d870509fe 190 This command will place Grbl into a de-powered sleep state, shutting down the spindle, coolant, and stepper enable pins and block any commands. It may only be exited by a soft-reset or power-cycle. Once re-initialized, Grbl will automatically enter an ALARM state, because it's not sure where it is due to the steppers being disabled.
Sergunb 0:8f0d870509fe 191
Sergunb 0:8f0d870509fe 192 This feature is useful if you need to automatically de-power everything at the end of a job by adding this command at the end of your g-code program, BUT, it is highly recommended that you add commands to first move your machine to a safe parking location prior to this sleep command. It also should be emphasized that you should have a reliable CNC machine that will disable everything when its supposed to, like your spindle. Grbl is not responsible for any damage it may cause. It's never a good idea to leave your machine unattended. So, use this command with the utmost caution!
Sergunb 0:8f0d870509fe 193
Sergunb 0:8f0d870509fe 194
Sergunb 0:8f0d870509fe 195 ***
Sergunb 0:8f0d870509fe 196
Sergunb 0:8f0d870509fe 197 ## Grbl v1.1 Realtime commands
Sergunb 0:8f0d870509fe 198
Sergunb 0:8f0d870509fe 199 Realtime commands are single control characters that may be sent to Grbl to command and perform an action in real-time. This means that they can be sent at anytime, anywhere, and Grbl will immediately respond, regardless of what it is doing at the time. These commands include a reset, feed hold, resume, status report query, and overrides (in v1.1).
Sergunb 0:8f0d870509fe 200
Sergunb 0:8f0d870509fe 201 A realtime command:
Sergunb 0:8f0d870509fe 202
Sergunb 0:8f0d870509fe 203 - Will execute within tens of milliseconds.
Sergunb 0:8f0d870509fe 204
Sergunb 0:8f0d870509fe 205 - Is a single character that may be sent to Grbl at any time.
Sergunb 0:8f0d870509fe 206
Sergunb 0:8f0d870509fe 207 - Does not require a line feed or carriage return after them.
Sergunb 0:8f0d870509fe 208
Sergunb 0:8f0d870509fe 209 - Is not considered a part of the streaming protocol.
Sergunb 0:8f0d870509fe 210
Sergunb 0:8f0d870509fe 211 - Are intercepted when they are received and never placed in a buffer to be parsed by Grbl.
Sergunb 0:8f0d870509fe 212
Sergunb 0:8f0d870509fe 213 - Will ignore multiple commands until it has executed the first received command.
Sergunb 0:8f0d870509fe 214
Sergunb 0:8f0d870509fe 215 - May be tied to an input pin and may be operated with a button or switch.
Sergunb 0:8f0d870509fe 216
Sergunb 0:8f0d870509fe 217 - Actions depends on state or what Grbl is doing. It may not do anything.
Sergunb 0:8f0d870509fe 218
Sergunb 0:8f0d870509fe 219 - Descriptions explain how they work and what to expect.
Sergunb 0:8f0d870509fe 220
Sergunb 0:8f0d870509fe 221 #### ASCII Realtime Command Descriptions
Sergunb 0:8f0d870509fe 222 Four realtime commands are type-able by users on a keyboard and shown in the `$` Grbl help message. These realtime command characters control some of Grbl's basic functions.
Sergunb 0:8f0d870509fe 223
Sergunb 0:8f0d870509fe 224 - `0x18` (ctrl-x) : Soft-Reset
Sergunb 0:8f0d870509fe 225
Sergunb 0:8f0d870509fe 226 - Immediately halts and safely resets Grbl without a power-cycle.
Sergunb 0:8f0d870509fe 227 - Accepts and executes this command at any time.
Sergunb 0:8f0d870509fe 228 - If reset while in motion, Grbl will throw an alarm to indicate position may be lost from the motion halt.
Sergunb 0:8f0d870509fe 229 - If reset while in not motion, position is retained and re-homing is not required.
Sergunb 0:8f0d870509fe 230 - An input pin is available to connect a button or switch.
Sergunb 0:8f0d870509fe 231
Sergunb 0:8f0d870509fe 232
Sergunb 0:8f0d870509fe 233 - `?` : Status Report Query
Sergunb 0:8f0d870509fe 234
Sergunb 0:8f0d870509fe 235 - Immediately generates and sends back runtime data with a status report.
Sergunb 0:8f0d870509fe 236 - Accepts and executes this command at any time, except during a homing cycle and when critical alarm (hard/soft limit error) is thrown.
Sergunb 0:8f0d870509fe 237
Sergunb 0:8f0d870509fe 238
Sergunb 0:8f0d870509fe 239 - `~` : Cycle Start / Resume
Sergunb 0:8f0d870509fe 240
Sergunb 0:8f0d870509fe 241 - Resumes a feed hold, a safety door/parking state when the door is closed, and the M0 program pause states.
Sergunb 0:8f0d870509fe 242 - Command is otherwise ignored.
Sergunb 0:8f0d870509fe 243 - If the parking compile-time option is enabled and the safety door state is ready to resume, Grbl will re-enable the spindle and coolant, move back into position, and then resume.
Sergunb 0:8f0d870509fe 244 - An input pin is available to connect a button or switch.
Sergunb 0:8f0d870509fe 245
Sergunb 0:8f0d870509fe 246
Sergunb 0:8f0d870509fe 247 - `!` : Feed Hold
Sergunb 0:8f0d870509fe 248
Sergunb 0:8f0d870509fe 249 - Places Grbl into a suspend or HOLD state. If in motion, the machine will decelerate to a stop and then be suspended.
Sergunb 0:8f0d870509fe 250 - Command executes when Grbl is in an IDLE, RUN, or JOG state. It is otherwise ignored.
Sergunb 0:8f0d870509fe 251 - If jogging, a feed hold will cancel the jog motion and flush all remaining jog motions in the planner buffer. The state will return from JOG to IDLE or DOOR, if was detected as ajar during the active hold.
Sergunb 0:8f0d870509fe 252 - By machine control definition, a feed hold does not disable the spindle or coolant. Only motion.
Sergunb 0:8f0d870509fe 253 - An input pin is available to connect a button or switch.
Sergunb 0:8f0d870509fe 254
Sergunb 0:8f0d870509fe 255
Sergunb 0:8f0d870509fe 256 #### Extended-ASCII Realtime Command Descriptions
Sergunb 0:8f0d870509fe 257
Sergunb 0:8f0d870509fe 258 Grbl v1.1 installed more than a dozen new realtime commands to control feed, rapid, and spindle overrides. To help prevent users from inadvertently altering overrides with a keystroke and allow for more commands later on, all of the new control characters have been moved to the extended ASCII character set. These are not easily type-able on a keyboard, but, depending on the OS, they may be entered using specific keystroke and code. GUI developers will need to be able to send extended ASCII characters, values `128 (0x80)` to `255 (0xFF)`, to Grbl to take advantage of these new features.
Sergunb 0:8f0d870509fe 259
Sergunb 0:8f0d870509fe 260 - `0x84` : Safety Door
Sergunb 0:8f0d870509fe 261
Sergunb 0:8f0d870509fe 262 - Although typically connected to an input pin to detect the opening of a safety door, this command allows a GUI to enact the safety door behavior with this command.
Sergunb 0:8f0d870509fe 263 - Immediately suspends into a DOOR state and disables the spindle and coolant. If in motion, the machine will decelerate to a stop and then be suspended.
Sergunb 0:8f0d870509fe 264 - If executed during homing, Grbl will instead halt motion and throw a homing alarm.
Sergunb 0:8f0d870509fe 265 - If already in a suspend state or HOLD, the DOOR state supersedes it.
Sergunb 0:8f0d870509fe 266 - If the parking compile-time option is enabled, Grbl will park the spindle to a specified location.
Sergunb 0:8f0d870509fe 267 - Command executes when Grbl is in an IDLE, HOLD, RUN, HOMING, or JOG state. It is otherwise ignored.
Sergunb 0:8f0d870509fe 268 - If jogging, a safety door will cancel the jog and all queued motions in the planner buffer. When the safety door is closed and resumed, Grbl will return to an IDLE state.
Sergunb 0:8f0d870509fe 269 - An input pin is available to connect a button or switch, if enabled with a compile-time option.
Sergunb 0:8f0d870509fe 270 - Some builds of Grbl v0.9 used the `@` character for this command, but it was undocumented. Moved to extended-ASCII to prevent accidental commanding.
Sergunb 0:8f0d870509fe 271
Sergunb 0:8f0d870509fe 272
Sergunb 0:8f0d870509fe 273 - `0x85` : Jog Cancel
Sergunb 0:8f0d870509fe 274
Sergunb 0:8f0d870509fe 275 - Immediately cancels the current jog state by a feed hold and automatically flushing any remaining jog commands in the buffer.
Sergunb 0:8f0d870509fe 276 - Command is ignored, if not in a JOG state or if jog cancel is already invoked and in-process.
Sergunb 0:8f0d870509fe 277 - Grbl will return to the IDLE state or the DOOR state, if the safety door was detected as ajar during the cancel.
Sergunb 0:8f0d870509fe 278
Sergunb 0:8f0d870509fe 279
Sergunb 0:8f0d870509fe 280 - Feed Overrides
Sergunb 0:8f0d870509fe 281
Sergunb 0:8f0d870509fe 282 - Immediately alters the feed override value. An active feed motion is altered within tens of milliseconds.
Sergunb 0:8f0d870509fe 283 - Does not alter rapid rates, which include G0, G28, and G30, or jog motions.
Sergunb 0:8f0d870509fe 284 - Feed override value can not be 10% or greater than 200%.
Sergunb 0:8f0d870509fe 285 - If feed override value does not change, the command is ignored.
Sergunb 0:8f0d870509fe 286 - Feed override range and increments may be changed in config.h.
Sergunb 0:8f0d870509fe 287 - The commands are:
Sergunb 0:8f0d870509fe 288 - `0x90` : Set 100% of programmed rate.
Sergunb 0:8f0d870509fe 289 - `0x91` : Increase 10%
Sergunb 0:8f0d870509fe 290 - `0x92` : Decrease 10%
Sergunb 0:8f0d870509fe 291 - `0x93` : Increase 1%
Sergunb 0:8f0d870509fe 292 - `0x94` : Decrease 1%
Sergunb 0:8f0d870509fe 293
Sergunb 0:8f0d870509fe 294
Sergunb 0:8f0d870509fe 295 - Rapid Overrides
Sergunb 0:8f0d870509fe 296
Sergunb 0:8f0d870509fe 297 - Immediately alters the rapid override value. An active rapid motion is altered within tens of milliseconds.
Sergunb 0:8f0d870509fe 298 - Only effects rapid motions, which include G0, G28, and G30.
Sergunb 0:8f0d870509fe 299 - If rapid override value does not change, the command is ignored.
Sergunb 0:8f0d870509fe 300 - Rapid override set values may be changed in config.h.
Sergunb 0:8f0d870509fe 301 - The commands are:
Sergunb 0:8f0d870509fe 302 - `0x95` : Set to 100% full rapid rate.
Sergunb 0:8f0d870509fe 303 - `0x96` : Set to 50% of rapid rate.
Sergunb 0:8f0d870509fe 304 - `0x97` : Set to 25% of rapid rate.
Sergunb 0:8f0d870509fe 305
Sergunb 0:8f0d870509fe 306
Sergunb 0:8f0d870509fe 307 - Spindle Speed Overrides
Sergunb 0:8f0d870509fe 308
Sergunb 0:8f0d870509fe 309 - Immediately alters the spindle speed override value. An active spindle speed is altered within tens of milliseconds.
Sergunb 0:8f0d870509fe 310 - Override values may be changed at any time, regardless of if the spindle is enabled or disabled.
Sergunb 0:8f0d870509fe 311 - Spindle override value can not be 10% or greater than 200%
Sergunb 0:8f0d870509fe 312 - If spindle override value does not change, the command is ignored.
Sergunb 0:8f0d870509fe 313 - Spindle override range and increments may be altered in config.h.
Sergunb 0:8f0d870509fe 314 - The commands are:
Sergunb 0:8f0d870509fe 315 - `0x99` : Set 100% of programmed spindle speed
Sergunb 0:8f0d870509fe 316 - `0x9A` : Increase 10%
Sergunb 0:8f0d870509fe 317 - `0x9B` : Decrease 10%
Sergunb 0:8f0d870509fe 318 - `0x9C` : Increase 1%
Sergunb 0:8f0d870509fe 319 - `0x9D` : Decrease 1%
Sergunb 0:8f0d870509fe 320
Sergunb 0:8f0d870509fe 321
Sergunb 0:8f0d870509fe 322 - `0x9E` : Toggle Spindle Stop
Sergunb 0:8f0d870509fe 323
Sergunb 0:8f0d870509fe 324 - Toggles spindle enable or disable state immediately, but only while in the HOLD state.
Sergunb 0:8f0d870509fe 325 - The command is otherwise ignored, especially while in motion. This prevents accidental disabling during a job that can either destroy the part/machine or cause personal injury. Industrial machines handle the spindle stop override similarly.
Sergunb 0:8f0d870509fe 326 - When motion restarts via cycle start, the last spindle state will be restored and wait 4.0 seconds (configurable) before resuming the tool path. This ensures the user doesn't forget to turn it back on.
Sergunb 0:8f0d870509fe 327 - While disabled, spindle speed override values may still be altered and will be in effect once the spindle is re-enabled.
Sergunb 0:8f0d870509fe 328 - If a safety door is opened, the DOOR state will supersede the spindle stop override, where it will manage the spindle re-energizing itself upon closing the door and resuming. The prior spindle stop override state is cleared and reset.
Sergunb 0:8f0d870509fe 329
Sergunb 0:8f0d870509fe 330
Sergunb 0:8f0d870509fe 331 - `0xA0` : Toggle Flood Coolant
Sergunb 0:8f0d870509fe 332
Sergunb 0:8f0d870509fe 333 - Toggles flood coolant state and output pin until the next toggle or g-code command alters it.
Sergunb 0:8f0d870509fe 334 - May be commanded at any time while in IDLE, RUN, or HOLD states. It is otherwise ignored.
Sergunb 0:8f0d870509fe 335 - This override directly changes the coolant modal state in the g-code parser. Grbl will continue to operate normally like it received and executed an `M8` or `M9` g-code command.
Sergunb 0:8f0d870509fe 336 - When `$G` g-code parser state is queried, the toggle override change will be reflected by an `M8` enabled or disabled with an `M9` or not appearing when `M7` is present.
Sergunb 0:8f0d870509fe 337
Sergunb 0:8f0d870509fe 338
Sergunb 0:8f0d870509fe 339 - `0xA1` : Toggle Mist Coolant
Sergunb 0:8f0d870509fe 340
Sergunb 0:8f0d870509fe 341 - Enabled by `ENABLE_M7` compile-time option. Default is disabled.
Sergunb 0:8f0d870509fe 342 - Toggles mist coolant state and output pin until the next toggle or g-code command alters it.
Sergunb 0:8f0d870509fe 343 - May be commanded at any time while in IDLE, RUN, or HOLD states. It is otherwise ignored.
Sergunb 0:8f0d870509fe 344 - This override directly changes the coolant modal state in the g-code parser. Grbl will continue to operate normally like it received and executed an `M7` or `M9` g-code command.
Sergunb 0:8f0d870509fe 345 - When `$G` g-code parser state is queried, the toggle override change will be reflected by an `M7` enabled or disabled with an `M9` or not appearing when `M8` is present.