Жидкокристаллические Индикаторы Википедия

---

This page tries to describe the flavour of G-codes that the RepRap firmwares use and how they work. The main target is additive fabrication using FFF processes. Codes for print head movements follow the NIST RSNGC G-code standard, so RepRap firmwares are quite usable for CNC milling and similar applications as well. See also on Wikipedia's G-code article.

There are a few different ways to prepare G-code for a printer. One method would be to use a slicing program such as Slic3r, Skeinforge or Cura. These programs import a CAD model, slice it into layers, and output the G-code required to print each layer. Slicers are the easiest way to go from a 3D model to a printed part, however the user sacrifices some flexibility when using them. Another option for G-code generation is to use a lower level library like mecode. Libraries like mecode give you precise control over the tool path, and thus are useful if you have a complex print that is not suitable for naive slicing. The final option is to just write the G-code yourself. This may be the best choice if you just need to run a few test lines while calibrating your printer.

As many different firmwares exist and their developers tend to implement new features without discussing strategies or looking what others did before them, a lot of different sub-flavours for the 3D-Printer specific codes developed over the years. This particular page is the master page for RepRap. Nowhere in here should the same code be used for two different things; there are always more numbers to use The rule is: add your new code here, then implement it.

Unfortunately human nature being what it is, the best procedures aren't always followed, so some multiple uses of the same code exist. The rule which should be followed is that later appearances of a code on this page (later than the original use of a code), are deprecated and should be changed, unless there is a good technical reason (like the general G-Code standard) why a later instance should be preferred. Note that the key date is appearance here, not date of implementation.

Introduction

A typical piece of G-code as sent to a RepRap machine might look like this:

N3 T0*57 N4 G92 E0*67 N5 G28*22 N6 G1 F*82 N7 G1 X Y F*85 N8 G1 X Y*33

G-code can also be stored in files on SD cards. A file containing RepRap G-code usually has the extension , or . Files for BFB/RapMan have the extension . G-code stored in file or produced by a slicer might look like this:

G92 E0 G28 G1 F G1 X Y F G1 X Y

The meaning of all those symbols and numbers (and more) is explained below.

Slicers will (optionally?) add G-code scripts to the beginning and end of their output file to perform specified actions before and/or after a print such as z-probing the build-area, heating/cooling the bed and hotend, performing ooze free "nozzle wipe" startup routine, switching system power on/off, and even "ejecting" parts. More info on the Start GCode routines and End GCode routines pages.

To find out which specific G-code(s) are implemented in any given firmware, there are little tables attached to the command descriptions, like this one:

Here means:

&#;???	Unknown if the firmware supports this G-code. You may want to test this yourself before using it in production.
Yes	The G-code is fully supported by the firmware.
+	The G-code is supported by version and above.
No	The firmware does not support the G-code at all.
Partial	There is only partial support for the full G-code specification. It may be required to rebuild the source code with extra options or flip configuration switches on the mainboard.
Experimental	The G-code is experimental and may change or be removed.
Automatic	The firmware handles this G-code automatically, so there's no need to send the command. An example is power supply on/off G-code (/) in the Teacup firmware.

For the technically-minded, G-code line endings are Unix Line Endings (), but will accept Windows Line Endings (), so you should not need to worry about converting between the two, but it is best practice to use Unix Line Endings where possible.

Fields

A RepRap G-code is a list of fields that are separated by white spaces or line breaks. A field can be interpreted as a command, parameter, or for any other special purpose. It consists of one letter directly followed by a number, or can be only a stand-alone letter (Flag). The letter gives information about the meaning of the field (see the list below in this section). Numbers can be integers () or fractional numbers (), depending on context. For example, an X coordinate can take integers () or fractionals (), but selecting extruder number would make no sense. In this description, the numbers in the fields are represented by as a placeholder.

In RepRapFirmware, some parameters can be followed by more than one number, with colon used to separate them. Typically this is used to specify extruder parameters, with one value provided per extruder. If only one value is provided where a value is needed for each extruder, then that value is applied to all extruders.

Letter	Meaning
Gnnn	Standard G-code command, such as move to a point
Mnnn	RepRap-defined command, such as turn on a cooling fan
Tnnn	Select tool nnn. In RepRap, a tool is typically associated with a nozzle, which may be fed by one or more extruders.
Snnn	Command parameter, such as time in seconds; temperatures; voltage to send to a motor
Pnnn	Command parameter, such as time in milliseconds; proportional (Kp) in PID Tuning
Xnnn	A X coordinate, usually to move to. This can be an Integer or Fractional number.
Ynnn	A Y coordinate, usually to move to. This can be an Integer or Fractional number.
Znnn	A Z coordinate, usually to move to. This can be an Integer or Fractional number.
U,V,W	Additional axis coordinates (RepRapFirmware)
Innn	Parameter - X-offset in arc move; integral (Ki) in PID Tuning
Jnnn	Parameter - Y-offset in arc move
Dnnn	Parameter - used for diameter; derivative (Kd) in PID Tuning
Hnnn	Parameter - used for heater number in PID Tuning
Fnnn	Feedrate in mm per minute. (Speed of print head movement)
Rnnn	Parameter - used for temperatures
Qnnn	Parameter - not currently used
Ennn	Length of extrudate. This is exactly like X, Y and Z, but for the length of filament to consume.
Nnnn	Line number. Used to request repeat transmission in the case of communications errors.
*nnn	Checksum. Used to check for communications errors.

Case sensitivity

The original NIST G-code standard requires gcode interpreters to be case-insensitive, except for characters in comments. However, not all 3D printer firmwares conform to this and some recognise uppercase command letters and parameters only.

Firmwares that are known to be case-insensitive

RepRapFirmware version and later (except within quoted strings)

Druid Firmware version by default is case-insensitive: ( M S0 = case-sensitive / M S1 = case-insensitive )

Firmwares that are known to be case-sensitive

RepRapFirmware version and earlier

Druid Firmware version for case-sensitive: M S0 = case-sensitive

Quoted strings

In RepRapFirmware, some commands support quoted strings when providing file names and other string parameters. This allows file names, WiFi passwords etc. to contain spaces, semicolons and other characters that would otherwise not be permitted. Double-quote characters are used to delimit the string, and any double-quote character within the string must be repeated.

Unfortunately, some gcode sender programs convert all characters to uppercase and don't provide any means to disable this feature. Therefore, within a quoted-string, the single-quote character is used as a flag to force the following character to lowercase. If you want to include a single quote character in the string, use two single quote characters to represent one single quote character.

Example: to add SSID MYROUTER with password to the WiFi network list, use command:

or if you can't send lowercase characters:

Using expressions in parameters

RepRapFirmware and later allow parameter values to be computed from an expression enclosed in { }. Such an expression may include constants, values from the machine object model, operators and functions. Example:

See eunic-brussels.eu#Section_Use_of_expressions_within_GCode_commands for more details.

G-code comments begin at a semicolon, and end at the end of the line:

N3 T0*57&#;; This is a comment N4 G92 E0*67 ; So is this N5 G28*22

Some firmwares also obey the CNC G-code standard, which is to enclose comments in round brackets. Comments of this form must start and end on the same line:

(Home some axes) G28 (here come the axes to be homed) X Y

Comments and white space will be ignored by your RepRap Printer. It's better to strip these out on the host computer before sending the G-code to your printer, as this saves bandwidth.

Special fields

N: Line number

Example

N

If present, the line number should be the first field in a line. For G-code stored in files on SD cards the line number is usually omitted.

If checking is supported, the RepRap firmware expects line numbers to increase by 1 each line, and if that doesn't happen it is flagged as an error. But you can reset the count using (see below).

Although supported, usage of N in Machinekit is discouraged as it serves no purpose.

*: Checksum

Example:

If present, the checksum should be the last field in a line, but before a comment. For G-code stored in files on SD cards the checksum is usually omitted.

The firmware compares the checksum against a locally-computed value. If they differ, it requests a repeat transmission of the line.

*: CRC

Example:

The 8-bit checksum provides insufficient protection against noise on the received data connection in some situations, for example where the cable from a display device runs close to an extruder cable. Therefore RepRapFirmware allows a CRC to be used in place of a checksum. If present, the CRC should be the last field in a line, but before a comment. RepRapFirmware assumes that * followed by 5 digits is a CRC, whereas * followed by 1, 2 or 3 digits is a checksum. The polynomial used is 0x as for CCITT CRC

Checking

Example

N [G Code in here] *71

The RepRap firmware checks the line number and the checksum (or CRC if supported). You can leave both of these out - RepRap will still work, but it won't do checking. You have to have both or neither though. If only one appears, it produces an error.

The checksum "cs" for a G-code string "cmd" (including its line number) is computed by exor-ing the bytes in the string up to and not including the * character as follows:

int cs = 0; for(i = 0; cmd[i]&#;!= '*' && cmd[i]&#;!= NULL; i++) cs = cs ^ cmd[i]; cs &= 0xff; // Defensive programming

and the value is appended as a decimal integer to the command after the * character.

Conditional Execution and Loops

RepRapFirmware and later supports conditions and loops in GCode. Properties from the firmware object model (e.g. current position, current tool) can be included in controlling expressions. See eunic-brussels.eu for details.

Buffering

If buffering is supported, the RepRap firmware stores some commands in a ring buffer internally for execution. This means that there is no (appreciable) delay while a command is acknowledged and the next transmitted. In turn, this means that sequences of line segments can be plotted without a dwell between one and the next. As soon as one of these buffered commands is received it is acknowledged and stored locally. If the local buffer is full, then the acknowledgment is delayed until space for storage in the buffer is available. This is how flow control is achieved.

Typically, the following moving commands are buffered: - and -. The Teacup Firmware buffers also some setting commands: , , and . All other , or commands are not buffered.

RepRapFirmware also implements an internal queue to ensure that certain codes (like M) are executed in the right order and not when the last move has been added to the look-ahead queue.

When an unbuffered command is received it is stored, but it is not acknowledged to the host until the buffer is exhausted and then the command has been executed. Thus the host will pause at one of these commands until it has been done. Short pauses between these commands and any that might follow them do not affect the performance of the machine.

G-commands

G0 & G1: Move

• &#;: Rapid Move
• &#;: Linear Move

Usage

Parameters

Not all parameters need to be used, but at least one has to be used

The position to move to on the X axis

The position to move to on the Y axis

The position to move to on the Z axis

The amount to extrude between the starting point and ending point

The feedrate per minute of the move between the starting point and ending point (if supplied)

(RepRapFirmware) Flag to check if an endstop was hit ( to check, to ignore, other see note, default is )¹

(RepRapFirmware) Restore point number ⁴

Laser cutter/engraver power. In RepRapFirmware, when not in laser mode S in interpreted the same as H.

Examples

G0 X12 &#;; move to 12mm on the X axis G0 F &#;; Set the feedrate to mm/min G1 X Y E&#;; Move to mm on the X axis and mm on the Y axis while extruding mm of material

The RepRap firmware spec treats and as the same command, since it's just as efficient as not doing so.²

Most RepRap firmwares do subtle things with feedrates.

G1 F &#;; Set feedrate to mm/min G1 X50 Y E&#;; Move and extrude

In the above example, we first set the feedrate to mm/min, then move to 50mm on X and mm on Y while extruding mm of filament between the two points.

G1 F &#;; Feedrate mm/min G1 X50 Y E F&#;; Accelerate to mm/min

However, in the above example, we set a feedrate of mm/min, then do the same move, but accelerating to mm/min. Everything stays synchronized, so extrusion accelerates right along with X and Y movement.

The RepRap spec treats the feedrate as simply another variable (like X, Y, Z, and E) to be linearly interpolated. This gives complete control over the acceleration and deceleration of the printer head in a way that ensures everything moves smoothly together and the right volume of material is extruded at all points.³

To reverse the extruder by a given amount (for example to reduce its internal pressure while it does an in-air movement so that it doesn't dribble) simply use or to send an value that is less than the currently extruded length.

Notes

¹Some firmwares allow for the RepRap to enable or disable the "sensing" of endstops during a move. Please check with whatever firmware you are using to see if they support the parameter in this way, as damage may occur if you assume incorrectly. In RepRapFirmware, using the or parameter on a delta printer causes the parameters to refer to the individual tower motor positions instead of the head position, and to enable endstop detection as well if the parameter is H1. H3 may be used to measure axis lengths and H4 can be used to stop when an endstop is hit while updating the position only (H4 is supported in b4 and later).

²In the RSNGC Spec, is Rapid Move, which was used to move between the current point in space and the new point as quickly and efficiently as possible, and is Controlled Move, which was used to move between the current point in space and the new point as precise as possible. In RepRapFirmware, G1 is always a linear move but G0 may not be linear (e.g. on a SCARA machine); however a G0 move will never go below the lower of the initial and final Z height of the move.

³Some firmwares may not support setting the feedrate inline with a move.

⁴RepRapFirmware provides an additional 'R' parameter to tell the machine to add the coordinates of the specified restore point to all axis coordinates mentioned in the G0 or G1 command. Axes that are not mentioned in the G0 or G1 command are not moved. When a print is paused, the coordinates are saved in restore point #1. When a tool change is commenced, the coordinates are saved in restore point #2. Coordinates can also be saved in restore points explicity using the G60 command.

Some older machines, CNC or otherwise, used to move faster if they did not move in a straight line. This is also true for some non-Cartesian printers, like delta or polar printers, which move easier and faster in a curve.

G2 & G3: Controlled Arc Move

Usage

(Clockwise Arc)

(Counter-Clockwise Arc)

Parameters

The position to move to on the X axis

The position to move to on the Y axis

The point in X space from the current X position to maintain a constant distance from

The point in Y space from the current Y position to maintain a constant distance from

The amount to extrude between the starting point and ending point

The feedrate per minute of the move between the starting point and ending point (if supplied)

Examples

G2 X Y I5 J10 E

(Move in a Clockwise arc from the current point to point (X=,Y=), with a center point at (X=current_X+5, Y=current_Y+10), extruding mm of material between starting and stopping)

G3 X Y I5 J10 E

(Move in a Counter-Clockwise arc from the current point to point (X=,Y=), with a center point at (X=current_X+5, Y=current_Y+10), extruding mm of material between starting and stopping)

Notes

¹In Marlin Firmware not implemented for DELTA printers.

²Prusa Firmware implements arcs only in Cartesian XY.

³On Klipper, a section must be enabled in the configuration file.

G4: Dwell

Pause the machine for a period of time.

Parameters

Time to wait, in milliseconds (In Teacup, P0, wait until all previous moves are finished)

Time to wait, in seconds (Only on Repetier, Marlin, Prusa, Smoothieware, and RepRapFirmware and later)

Example

G4 P

In this case sit still doing nothing for milliseconds. During delays the state of the machine (for example the temperatures of its extruders) will still be preserved and controlled.

On Marlin, Smoothie and RepRapFirmware, the "S" parameter will wait for seconds, while the "P" parameter will wait for milliseconds. "G4 S2" and "G4 P" are equivalent.

G6: Direct Stepper Move

Perform a direct, uninterpolated, and non-kinematic synchronized move of one or more steppers directly. Units may be linear (e.g., mm or inches on ) or specified in degrees (SCARA). This command is useful for initialization, diagnostics, and calibration, and should be disabled on production equipment. This type of move can be potentially dangerous, especially for deltabots, so implementations should do their best to limit movement to prevent twerking and damaging the carriage assembly.

Parameters

Stepper A position or angle

Stepper B position or angle

Stepper C position or angle

Relative move flag

SCARA Examples

G6 A45 &#;; Move SCARA A stepper to the 45° position G6 B20 R &#;; Move SCARA B stepper 20° counter-clockwise

DELTA Example

G6 C10 R &#;; Move DELTA C carriage up by 10mm

G Set tool Offset and/or workplace coordinates and/or tool temperatures

Usage

¹

Parameters

Tool number

Offset mode ⁵

X offset

Y offset

Z offset²

other axis offsets⁴

Standby temperature(s) (RepRapFirmware)

Active temperature(s) (RepRapFirmware)

Examples

G10 L1 P2 X Y Z

(sets the offset for tool 2 to the X, Y, and Z values specified)

G10 P1 R S

(RepRapFirmware only - set standby and active temperatures³ for tool 1)

Remember that any parameter that you don't specify will automatically be set to the last value for that parameter. That usually means that you want explicitly to set Z RepRapFirmware will report the tool parameters if only the tool number is specified.

The precise meaning of the X, Y (and other offset) values is: with no offset this tool is at this position relative to where a tool with offset (0, 0, 0) would be. So if the tool is 10mm to the left of a zero-offset tool the X value would be , and so on.

The value is the standby temperature in ^oC that will be used for the tool, and the value is its operating temperature. If you don't want the tool to be at a different temperature when not in use, set both values the same. See the T code (select tool) below. In tools with multiple heaters the temperatures for them all are specified thus: R S .

See also .

Notes

¹Marlin uses G10/G11 for executing a retraction/unretraction move. Smoothie uses for retract and for setting workspace coordinates. RepRapFirmware interprets a G10 command with no P or L parameter as a retraction command.

²It's usually a bad idea to put a non-zero value in as well unless the tools are loaded and unloaded by some sort of tool changer or are on indepedent carriages. When all the tools are in the machine at once they should all be set to the same Z height.

³If the absolute zero temperature () is passed as active and standby temperatures, RepRapFirmware will only switch off the tool heater(s) without changing their preset active or standby temperatures. RepRapFirmware-dc42 does not support this setting.

⁴Tool offsets are applied after any X axis mapping has been performed. Therefore if for example you map X to U in your command to create the tool, you should specify a U offset not an X offset. If you map X to both X and U, you can specify both offsets. (Not supported on all firmwares).

⁵L1 sets the offsets of the specified tool relative to the head reference point to the specified values. L2 sets the current workplace coordinate offsets to the specified values. L20 adjusts the current workplace coordinate offsets so that the current tool head position has the specified coordinates. NOTE on some firmwares L is required (and is required by NIST standard). P is also required to specify either the tool to update or the WCS to update.

G Retract

Parameters

retract length (S1 = long retract, S0 = short retract = default) (Repetier only)

Example

G10

Retracts filament according to settings of (Marlin, RepRapFirmware) or according to the value (Repetier).

RepRapFirmware recognizes as a command to set tool offsets and/or temperatures if the parameter is present, and as a retraction command if it is absent.

G Unretract

Parameters

retract length (S1 = long retract, S0 = short retract = default) (Repetier only)

Example

G11

Unretracts/recovers filament according to settings of (Marlin, RepRapFirmware) or according to the value (Repetier).

G Clean Tool

Usage

[P<0 1>] [S<count>] [T<count>]

Parameters

¹ Pattern style selection

Number of strokes (i.e. back-and-forth movements)

Number of repetitions

0=Never 1=Always apply software endstops (Marlin +)

Examples

G12&#;; stroke pattern (default)

To generate a three triangle zig-zag pattern which will be stroked three times time use the following command. G12 P1 S3 T2&#;; zig-zag pattern with 2 triangles

Notes

¹In Marlin firmware and Derivatives Mk4duo this is implemented by hard-coded firmware behaviours As defined for variables NOZZLE_CLEAN_STROKES, NOZZLE_CLEAN_START_POINT, NOZZLE_CLEAN_END_POINT and NOZZLE_CLEAN_PARK.

With NOZZLE_CLEAN_PARK enabled, the nozzle will automatically return to the XYZ position after G12 is run.

More on this behaviour is documented inside of the code base.

The use of G12 for tool cleaning clashes with the established use of G12 for circular pocket milling on CNC machines. For this reason, RepRapFirmware does not support G

G Plane Selection (CNC specific)