RepRapFirmware config files

Unlike Marlin and most other firmwares, RepRap Firmware does not require recompilation for different printers. The changes that you would normally make to configuration.h in Marlin are now all made with gcode. At the most basic level you can type gcode commands into pronterface each time you want to setup the printer - however that would quickly get very tedious. Instead the printer configuration is set within /sys/config.g on the SD card.

This tutorial will walk through the common parts of config.g for a Mendel90 style printer with dual extruders. If you have a single extruder printer then the comments will highlight what to leave out. It is assumed you are using DC42's fork of the RepRap Firmware and was written while version 1.00f was the most current version.

It is helpful if you refer to the gcode page on the reprap wiki as you follow along.

The order of the commands is not always strictly important however in some cases it is, for example you should define your tools before setting their offsets.

Gcode format

in general gcodes are formatted in the following manner:

[gcode_letter][number] [switch][information] [switch][information]

example

G1 X10 F3000

So its a "G" command, number "1", with the first switch being "X" with the information "10", the second switch being "F" with the information "3000". This command moves (G1) 10mm in X (X10) at 3000mm/m (F3000)

Another example is

M550 PMendel90 

Where The command is an "M" command, with the switch "P" and the information "Mendel90". This sets the printer name to "Mendel90".

Name and Networking

Much of this is similar to the RepRap Ormerod at this point as it is the same for most machines:

; Configuration file for Mendel90 Example

; Think3dprint3d.com

;

M111 S0                             ; Debug off

M550 PMendel90                      ; Machine name (can be anything you like)

M551 Preprap                        ; Machine password (currently not used)

M540 PBE:EF:DE:AD:FE:ED             ; MAC Address

M552 P192.168.1.14                  ; IP address

M553 P255.255.255.0                 ; Netmask

M554 P192.168.1.1                   ; Gateway

M555 P2                             ; Set output to look like Marlin

G21                                 ; Work in millimetres

G90                                 ; Send absolute coordinates...

M83                                   ; ...but relative extruder moves

You should set the IP address to be within the same subnet as your network, and not to an address that could be allocated to something else (eg, outside of your DHCP range). The MAC address should not be the same as one already on your network.

M83 sets the extruder to relative extruder moves which is intuitive when sending gcode commands by hand to move the extruder - for example when doing calibration. Cura (and Slic3r by default) expect gcodes to be absolute, rather than relative so I add M82 to the start.gcode to ensure when printing the firmware is in absolute gcode mode.

Set Axis and drives

;axis & drives setup
M906 X800 Y800 Z800 E800:800  ; Motor currents (mA) (Extruder set below)
M92 X80 Y80 Z4000             ; axis steps/mm
M92 E649:639                  ; Set extruder steps/mm
;set axis/drive directions
M569 P0 S1                    ;x axis +'ve
M569 P1 S0                    ;y axis -'ve
M569 P2 S0                    ;z axis -'ve
M569 P3 S0                    ;E0 drive -'ve
M569 P4 S1                    ;E1 drive +'ve
M201 X800 Y800 Z15 E2000            ; Accelerations (mm/s^2)
M203 X15000 Y15000 Z180 E3600       ; Maximum speeds (mm/min)

M566 X600 Y600 Z30 E20              ; Minimum speeds mm/minute

The Duet and Duex4 have digital control of the stepper current - this is set with M906, note the extruder parameter is delimited with a colon ":", this allows for different currents to be set of each extruder drive. This same delimitation is used for M92, allowing different extruder steps/mm to be set for each drive.

M569 sets the axis direction, in this example the printer is wired up in such a manner that X and E0 move in the +'ve direction when a positive movement is send, however Y,Z and E1 move in the negative direction. To correct that the switch "S0" is used, after this command a positive movement to Y,Z or E1 will move them in a positive direction.

M566 is the minimum or instantaneous speed change numbers, they are referred to as X,Y or E Jerk in Marlin. In all these cases I have used a single number for E, that sets the same for all extruders. if your extruders have different designs then you may want to set different speeds and accelerations for each one.

Thermal Settings

;Thermal Settings
M305 P1 R1000 B4267.0          ;1K bias resistor, B value  for Semitec 104-GT2
M305 P1 T100000                ;100K thermistor
M305 P2 R1000 B4267.0          ;1K bias resistor, B value  for Semitec 104-GT2
M305 P2 T100000                ;100K thermistor       
M305 P0 R1000 B4540            ;1K bias resistor,B value for Epcos B57861S104F40
M305 P2 T100000                ;100K thermistor  
M140 S0 R0                     ;set the bed to "0,0" at start up

M305 sets the heater thermistor information. P1 = hotend 0, P2= hotend 1, P0 = Heated bed. R1000 = a 1K bias resistor, if you are using a RepRapPro Duet then use R4700 as they use a 4.7k bias resistor. T100000 = 100K @25C thermistor. Finally all heaters are set to -273C by default so the M140 sets the bed to 0 active, 0 standby at startup which helps when using a control panel such as the PanelDue to control the printer. The hotend stat values are set later.

Define Tools

M563 P1 D0 H1                       ; Define tool 1
M563 P2 D1 H2                       ; Define tool 2
M563 P3 D0:1 H1                     ; Define tool 3

RepRap Firmware modifies the concept of a "Tool". No longer does the tool change commands "T0", "T1" etc, select an extruder drive and hotend combination that is designed into the printer with no easy way to change it, other than change the hardware. A tool now consists of any number of extruder drives, and heater combinations. The first line above

M563 P1 D0 H1                       ; Define tool 1

defines a tool (number 1, "P1")  that uses drive 0 (the first extruder drive, E0), and the second heater ("H1"). It is important to remember that the Heated Bed is the first heater configured in firmware, so the extruder 0 heater is H1. In a similar manner the second line

M563 P2 D1 H2                       ; Define tool 2

defines tool number 2 which uses the second drive (D1) and the third heater, which is the E1 heater (H2).

The third tool define is where it gets interesting and shows off the potential power of this method of defining tools.

M563 P3 D0:1 H1                     ; Define tool 3

This defines tool 3 to use both drive 0 and drive 1, but just heater 1. This sort of tool would fit a hotend like e3d's Cyclops.

Set offsets

RepRap Firmware can use G10 to set temperature and position offsets.

G10 P1 S0 R0                        ; Set tool 1 operating and standby temperatures
G10 P2 S0 R0                        ; Set tool 2 operating and standby temperatures
G10 P2 X18                          ; Set tool 2 offset on X axis

The first line sets the active and standby temperature of Tool 1 to 0, the second does the same for tool 2. The third sets the X offset to +18 for Tool 2, the second nozzle on an e3d Chimera is in line on Y but +18 on X, an alternative would be:

G10 P2 X-9                          ; Set tool 2 offset on X axis
G10 P2 X9                          ; Set tool 2 offset on X axis

Which would keep the hotends centered around 0,0 - better for a delta printer.

That concludes the config.g settings required for a standard cartesian printer.

Other files within the /sys/ directory

The concept of using gcodes to perform all printer functions, rather than precompiled routines extends to homing, probing and tool changes. Also within /sys/ on the SD card are the following files as standard

homeall.g
homex.g
homey.g
homez.g
tfree1.g
tfree2.g
tpost1.g
tpost2.g
tpre1.g
tpre2.g

Homing routines are galled in the notmal manner (G28 X for home x for example) however when that command is set, the RepRap Firmware uses the gcode within the relevant "home__.g" file to perform the homing. For example homex.g:

G90                 ; absolute movement
G92 X0              ; set X to 0
G1 X300 F6000 S1    ; move  fast to a large +'ve value, stop when an endstop is hit
G92 X200            ; set X to value of X max
G1 X195 F200        ; move back 5 mm
G1 X205 F200 S1     ; move forward again, slowly stop when endstop hit
G92 X200            ; set X to value of X max

This routine will home quickly until the endstop is reached, the back away and home slowly until its reached again. It makes use of the addition "S1" to the G1 command which stops when an endstop is triggered. Note that our mendel90s home to Max on all axis.

"homeall.g" would normally be a combination of homex.g, homey.g and homez.g:

G90                 ; absolute movement
;home X
G92 X0              ; set X to 0
G1 X300 F6000 S1    ; move fast to a large +'ve value, stop when an endstop is hit
G92 X180            ; set X to value of X max
G1 X175 F200        ; move back 5 mm
G1 X185 F200 S1     ; move forward again, slowly stop when endstop hit
G92 X180            ; set X to value of X max

;home Y
G92 Y0              ; set Y to 0
G1 Y300 F6000 S1    ; move fast to a large +'ve value, stop when an endstop is hit
G92 Y190            ; set Y to value of Y max
G1 Y185 F200        ; move back 5 mm
G1 Y195 F200 S1     ; move forward again, slowly stop when endstop hit
G92 Y190            ; set Y to value of Y max

G1 X100 F6000       ; center the X carriage before homing Z to clear the bowden tubes

;home Z
G92 Z0              ; set Z to 0
G1 Z300 F200 S1     ; move fast to a large +'ve value, stop when an endstop is hit
G92 Z200.85         ; set Z to value of Z max
G1 Z195 F200        ; move back 5 mm
G1 Z205 F60 S1     ; move forward again, slowly stop when endstop hit
G92 Z200.85         ; set Z to value of Z max

Note the "G1 X100 F6000 line before the Z home. This means that the X carriage will be centered before homing Z, ensuring that the bowden tubes pass easily out of the enclosure. 

The "Tfree1.g" etc are called on tool change in the following way:

TfreeN.g is run when tool N is freed

TpreN.g is run before tool N is set active

TpostN.g is run after tool N is set active

so for example in Tpost1.g you may have:

M116 P1

to wait for tool 1 to get to temperature before continuing with the print.

Or you may have

G1 X10 Y10 F6000

in Tfree1.g to move the extruder outside of the object being printed before changing tools. 

DC42 is working on further macros, specifically for Delta printers and probing. Examples of these can be seen here.

Web Interface Upload

You can use the web interface to upload all the modified files so changes are very quick and easy to make and save:

You can also view the current config.g contents in the web interface.

Basic Marlin Configuration.h modification

In order to set up Marlin firmware to work with your 3D printer the Configuration.h file needs to be modified to match your hardware. This post will describe the basics of modifying Configuration.h.

The version of Marlin this is based on is the current (as at 15/05/13) Marlin_v1 version, modified slightly to incorporate the Think3dPrint3d Panelolu2. There are various different Marlin versions:

EricZalm master version
Think3DPrint3D version
RepRapPro version
Nophead version

This post is aimed at helping users of RepRapPro Marlin and Nophead's Marlin migrate their configurations to T3P3 Marlin in order to use the Panelolu2; however it may be helpful to others who are setting up their configuration.h for the first time.

Refer to the working/default Configuration.h from your current setup if you have one and use that as a guide to what settings to put at each stage - if in doubt use the default setting from your printer manufacturer as a start point.

Note: I do not cover every setting, just the main ones to get up and printing.

Environment

The T3P3 version of Marlin is only tested on Arduino-0023 and on the following electronics boards:

Sanguinololu 1.2, and 1.3a
Melzi
RAMPS 1.3 and 1.4
Printrboard

First open Configuration.h in your favourite text editor or the Arduino IDE (it is located in <Marlin Folder>\Marlin\Configuration.h)

(from this point on I am not going to use screen shots for each Configuration.h line)

I will refer to the line number in the version of the T3P3 firmware available today. This will change over time and get out of date but it will be a good start and it should be fairly obvious which line I am referring to. You can see the line number on the bottom left of the Arduino IDE screen - in the shot above the cursor is on line 12.

Add an Author/Version

Line 12
#define STRING_CONFIG_H_AUTHOR "(<something useful here>)" //Who made the changes.

This is helpful to confirm with a glance which version of your configuration.h is loaded on your hardware:

Baudrate

Line 20
// This determines the communication speed of the printer
#define BAUDRATE 250000
//#define BAUDRATE 115200


Keep this on the faster setting unless you have a need to use a slower setting. Make sure you select the same baudrate in Pronterface (or your control software) as you have set here when you connect.

Motherboard

Line 51
#define MOTHERBOARD 7

As the comment above this line shows there are many supported electronics motherboards. Make sure you chose the right version for your electronics (for example 63 for Melzi, 33 for RAMPS 1.3/1.4 with 1 extruder, 34 for RAMPS 1.3/1.4 with 2 extruders etc).

Temperature Measurement

Line 90
#define TEMP_SENSOR_0 1
#define TEMP_SENSOR_1 0
#define TEMP_SENSOR_2 0
#define TEMP_SENSOR_BED 1

Most printers will use a thermistor, and a common choice is the "EPCOS B57560G104F". The standard table number "1" works fine for this thermistor. I have copied two tables from Nophead's version of Marlin into the T3P3 version - numbers 11 and 12. If you have a Mendel90 kit from Nophead then these will probably be the best choice for you (although they were numbered 8 and 9 in Nophead's version, I had to change the numbering as 8 and 9 were already taken in the master version).

If you have a RepRapPro printer, their custom version of Marlin does not use a pre-calculated thermistor lookup table but computes the values directly. I have incorporated this into the latest T3P3 version on Marlin as described in my previous blog post. My copy is rather untested so use with caution. Even though on-the-fly calculation is now available, I recommend using tables. Nophead's blog describes the theory behind the table calculations and the "createTemperatureLookupMarlin.py" script in the Marlin folder allows for the calculation of an accurate table for your thermistor and temperature range of interest.

If you want to use the calculated thermistor values then:

Line 97
//use RepRapPro Algebraic Temperature calculation rather than
//the tables - still experimental in this version of Marlin.
#define ALGEBRA_TEMP 

Line 104 onwards
Choose the serial resistor for your electronics (4700 is standard)

#define SERIAL_R 4700
//#define SERIAL_R 10000

Choose your thermistor Beta values (from the data sheet, ask your supplier) and value at 25C (100K thermistor is 100000, 10K is 10000)

// EPCOS B57560G104F (the standard 100K one)
#define E_BETA 4036.0
#define E_NTC 100000.0
#define BED_BETA 4036.0
#define BED_NTC 100000.0

Other standard thermistor types that RepRapPro uses are already in configuration.h, commented out. If you change to these types then comment out the lines referring to the EPCOS and uncomment the lines for the thermistor values that match yours. For example to use the latest RepRapPro thermistor values comment out:


// EPCOS B57560G104F (the standard 100K one)
//#define E_BETA 4036.0
//#define E_NTC 100000.0
//#define BED_BETA 4036.0
//#define BED_NTC 100000.0

and uncomment

// RS 198-961

#define E_BETA 3960.0

#define E_NTC 100000.0

// Rapid 61-0446 ; Semitec 103GT-2 All RepRapPRo Mendels and Thermistors shipped after 1/4/13

#define BED_BETA 4126.0

#define BED_NTC 10000.0

Temperature at Print Start

Line 137
#define TEMP_RESIDENCY_TIME 10 // (seconds)
#define TEMP_HYSTERESIS 3       // (degC) range of +/- temperatures considered "close" to the target one
#define TEMP_WINDOW     1 // (degC) Window around target to start the residency timer x degC early.

These allow you to control how close to the exact set temperature the thermistor reading needs to be to begin extruding. The defaults work OK, however to get a quicker start, I change my TEMP_RESIDENCY_TIME to "5" and TEMP_WINDOW to "2".

Max and Min Temperatures

The printer will give an error if the temperatures are outside of these values. I find that in a cold garage in winter the MIN_TEMPs need to be "1" rather than "5". Don't comment out or set to 0 or else the hotend could overheat if the thermistor is disconnected or breaks.

Line 144-155
#define HEATER_0_MINTEMP 1
....
#define HEATER_0_MAXTEMP 275
....

PID Temperature control

In order to get more stable extruder temperature control the use of PID control is recommended. To enable it ensure PIDTEMP is uncommented.

Line 164
#define PIDTEMP

You need to set the PID constants specific to your hotend. See Wikipedia theory on PID control if interested (not required to make this work):-

Line 178 onwards
    #define  DEFAULT_Kp 22.2
    #define  DEFAULT_Ki 1.08  
    #define  DEFAULT_Kd 114 

By far the easiest way to calculate these is to use PID autotune once your firmware is uploaded to your printer. This function experiments with the reaction of your hotend and calculates the best PID values. For more detail of PID autotune check this wiki entry. Once you have the values you can save them to EEPROM (see the section later in this guide about enabling EEPROM) or you can replace the values in the firmware (at line 178 as shown above) and re-upload your firmware.

You can use PID on the heated bed in a similar manner but I don't find it necessary. To do so uncomment PID_TEMP_BED:

Line 203
#define PIDTEMPBED

and define the constants for your bed. It is best to use PID autotune for this as well, choosing a different target temperature, as suggested in the Marlin comment:

"FIND YOUR OWN: "M303 E-1 C8 S90" to run autotune on the bed at 90 degreesC for 8 cycles."

Line 216
    #define  DEFAULT_bedKp 10.00
    #define  DEFAULT_bedKi .023
    #define  DEFAULT_bedKd 305.4

Extruder protection

The following lines prevent extrusion when conditions are not right.

Line 233
#define PREVENT_DANGEROUS_EXTRUDE
#define PREVENT_LENGTHY_EXTRUDE

Only comment them out to override the effect they have if you have a specific reason for doing so.

Endstops

For Sanguinololu, RAMPS, Melzi and most other common electronics all the endstop pullups should be on - ensure line 248 is uncommented:

Line 248
#define ENDSTOPPULLUPS

Generally you want the endstops to trigger when open: this is controlled with the following lines:

Line 270
const bool X_ENDSTOPS_INVERTING = false; // set to true to invert the logic of the endstops. 
const bool Y_ENDSTOPS_INVERTING = false; // set to true to invert the logic of the endstops. 
const bool Z_ENDSTOPS_INVERTING = false; // set to true to invert the logic of the endstops. 

For more information on endstops and why it is generally better to have Normally Closed Endstops have a look at this part of the Reprap wiki and the linked forum post.

Axis direction is controlled by the motor wiring and by these lines:

Line 287
#define INVERT_X_DIR false    // for Mendel set to false, for Orca set to true
#define INVERT_Y_DIR false    // for Mendel set to true, for Orca set to false
#define INVERT_Z_DIR true     // for Mendel set to false, for Orca set to true

Many printers only have 3 endstops, one per axis, so you have to tell the firmware which end to home towards:

Line 296
// Sets direction of endstops when homing; 1=MAX, -1=MIN
#define X_HOME_DIR -1
#define Y_HOME_DIR -1
#define Z_HOME_DIR -1

This combined with the length of the axis sets the dimensions of the printer. It is worth using software endstops to keep the print head within the print area during normal operation:

These need to be set to the correct values for your printer or else you can command the printer to move outside of the area it can cover and potentially cause damage.

Line 300
#define min_software_endstops true //If true, axis won't move to coordinates less than HOME_POS.
#define max_software_endstops true  //If true, axis won't move to coordinates greater than the defined lengths below.
// Travel limits after homing
#define X_MAX_POS 205
#define X_MIN_POS 0
#define Y_MAX_POS 205
#define Y_MIN_POS 0
#define Z_MAX_POS 200
#define Z_MIN_POS 0

I find that it is safest with a new printer to set the MAX_POS values to less than the maximum theoretical sizes, then physically check how much more travel is possible and adjust the values upwards if appropriate.

Movement Settings

These settings define how fast your printer's axis move and set the accuracy of moves. In most cases there will be a direct copy from the configuration.h file of your printer supplier. First is the speed the axes move during homing; this is in mm/s and the format X,Y,Z,E. E is 0 because the extruder is not homed.

Line 325
#define HOMING_FEEDRATE {50*60, 50*60, 4*60, 0}  // set the homing speeds (mm/min)


The next line defines how many steps of the stepper motor are required to move an axis by 1mm. Getting this wrong means the printer axis will not move the right distance. You MUST change the settings from the defaults (unless you actually have an Ultimaker!). Once again the format is  X, Y, Z, E. Prusa's calculator is very helpful for calculating the appropriate X, Y and Z values for your stepper motors, belt pitch and pulley teeth. For E, because hobbed bolts all vary slightly, the only way to get the correct value is to start with a reasonable value (e.g. 700 for a Wade's) and calibrate your extruder: RichRap's Slic3r blog provides detailed instructions for doing this.

Line 329
#define DEFAULT_AXIS_STEPS_PER_UNIT   {78.7402,78.7402,200.0*8/3,760*1.1}  // default steps per unit for ultimaker

The following lines set the speed and acceleration of your printer. Often the quality of prints can be improved by using slower acceleration values and smaller XYJERK values. They definitely need setting down for less-rigid machines with threaded-rod frames. Check the default values in the Marlin as supplied with your machine and use these to start with.

Line 330 Onwards

#define DEFAULT_MAX_FEEDRATE          {500, 500, 5, 25}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {9000,9000,100,10000}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION          3000    // X, Y, Z and E max acceleration in mm/s^2 for printing moves 
#define DEFAULT_RETRACT_ACCELERATION  3000   // X, Y, Z and E max acceleration in mm/s^2 for r retracts

// The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously)
#define DEFAULT_XYJERK                20.0    // (mm/sec)
#define DEFAULT_ZJERK                 0.4     // (mm/sec)
#define DEFAULT_EJERK                 5.0    // (mm/sec)

EEPROM - Saving Settings without recompiling firmware

When EEPROM is enabled there are three locations where versions of the printer settings are stored.

1. Hard-coded in Firmware in Configuration.h.
2. In the running RAM of the microcontroller - not saved on power down or reset.
3. In EEPROM

If EEPROM is enabled the settings are loaded from EEPROM, not from the hard-coded values in Configuration.h. EEPROM settings can be updated using a series of "M" commands. See the G-Code page on the RepRap wiki for a description of all the G and M codes including those for saving and reading from EEPROM.

I recommend enabling EEPROM_SETTINGS and EEPROM_CHITCHAT
Line 356
//define this to enable eeprom support
#define EEPROM_SETTINGS
//to disable EEPROM Serial responses and decrease program space by ~1700 byte: comment this out:
// please keep turned on if you can.
#define EEPROM_CHITCHAT

Display Screens - Panelolu2

There are an increasing number of LCD screens supported by Marlin, but this post only covers the Panelolu2. To enable the Panelolu2 uncomment the following line:

Line 381

#define PANELOLU2

If you don't like the buzzer making a beep sound then comment out the PAN_BEEP

Line 386
 #define PAN_BEEP //comment out to disable buzzer

I recommend that you get your printer working without enabling the Panelolu2 first and then uncomment the #define PANELOLU2 line afterwards. Note that Marlin will hang if the PANELOLU2 is enabled but not connected.

Thats it!

Please feel free to leave useful links to further information in the comments to this blog post.