Fuction of GCodes in RepRap host software

Hi
I am trying to make another RepStrap machine based on EMC and i need to know the function of Gcodes that produced from the RepRap host software. I have study a few firmawares and i see that there are variations, so i am a bit confused of compatibility between Reprap host software and different firmwares. I will be glad if somebody can clarify which firmware is made for communication with RepRap host software.
In specific i need to know what are the units of E value (mm,steps,volume, something else), the functon of T codes and the function of M codes.
I found this page : [reprap.org]
But there is no M113 in here while there is in the code produced by RepRap host software and there is no mention to T codes.

Thank you in advance
Charalampos Alexopoulos

I generally use this as my reference: [reprap.org]
E codes are usually in mm of filament input into the extruder. The slicing program works out the volumes, and simply tells the extruder how many mm to extrude.
T codes are usually for different tools, not used in reprap afaik.
Some firmware does have different gcode uses, for example Marlin's are listed down the page here: [github.com]
However, Slic3r [slic3r.org] can slice objects and output code for Mach3/EMC. Why not use that?

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E codes are usually in mm of filament input into the extruder.

True for some slicers, others measure the output. So a G-code interpreter has to support both, usually by supporting variable STEPS_PER_MM_E.

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Thank you

Quote

I generally use this as my reference: [reprap.org]

This looks like what i was looking for.

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E codes are usually in mm of filament input into the extruder

Are you sure? In the following is a part of a test object. You can see E values like G1 E1250.0 without any move in the XY axes. I think that is too much for mm.

; GCode generated by RepRap Java Host Software
; Created: 2012-04-29:20-52-30
;#!RECTANGLE:
M110
G21
G90
M140 S66.0
T0
M113
G92 E0
G28 X0
G28 Y0
G28 Z0
M109 S205.0
G1 F2500.0
G1 E1250.0
G1 F1500.0
G1 F18000.0
G1 E1190.0
G1 F1500.0
G92 E0
;#!LAYER: 1/20
G92 E0
G92 E0
G92 E0
G92 E0
T1
M113
G92 E0
T0
M113
G1 F15.0
G1 Z0.0 F31.2
G1 F1500.0
G1 X0.4 Y0.4 F1899.4
G1 X0.8 Y0.8 F1500.0

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However, Slic3r [slic3r.org] can slice objects and output code for Mach3/EMC. Why not use that?

I was thinking about to use the official gcode generator. But i will investigate the Slic3 option.

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True for some slicers, others measure the output. So a G-code interpreter has to support both, usually by supporting variable STEPS_PER_MM_E.

My plan is to use as litle firmware as posible. The extruder motor will be controlled by EMC so i need to know what the E values represent to calibrate the fourth axle of EMC. This is one of the reasons that i prefer to use just one gcode generator.

Almost no one uses the RepRap java host. If you want prints that look anything like the high quality prints that have drawn you to build a reprap you will need to use slic3r or skeinforge and both of them have E as the input length of filament in mm's .

The RepRap host and old old versions of skeinforge used output length in mm's but it is almost impossible to calibrate and takes a year of tuning to get to the point you will be at after a day of using slic3r.

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The last couple of hours i am testing (playing) with slic3r. It produce a nice gcode that run in EMC2 with no modifications. Excelent slicer !!!

Thank you all

You can also check out Kisslicer, it's not open source but it is free (and FAST)

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www.Fablicator.com