Repetier Problem

Hi all,

I am trying to use Repetier as the host software but I am experiencing a problem with it.

As soon as Repetier connects, the hot end switches on and heats up to a preset temp. I have not been able to disable this action within Repetier, even setting the temps off and setting machine as cnc router.

The machine will not accept any gcode commands from the manual control until the hot end is at temp.
Once hot end is at temp, I can send a homing command and the machine responds. I have then to have a hot end wired at all times to get over this connection hurdle.

With pronterface there is no problem and the machine moves fine with a cold hot end, indicating that the firmware is
not the cause.

Even a resistor or thermistor makes no difference, although once the machine has gone through the connection/hotend heat/ homing cycle, only then will it work without the hot end heating.

So any ideas how to over-ride or eliminate this requirement. Should I contact Repetier about this instead? I can see that a heated hot end will soften any ooze left over from a previous print and so allow the Z homing without screw jacking the bed to destruction!

My machine uses a Melzi board with Marlin firmware.

I have no experience with a Melzi board, so I can’t help if that is the problem. In marlin there is a safe extrude setting that prevents the extruder from working before it gets up to temp. Maybe you changed that setting some how to work on all axis? Try without end stops as well, people tend to use them wrong initially. I have had several people having issues because of their end stops. I don’t recommend them they can be a hindrance in milling. You can plug them back in after it is working. Maybe there is a setting in repetier but it is not on by default. So maybe uninstall and reinstall.

Thanks for the response.
At the moment I will stick to pronterface as the machine control system as it appears to work well. Can’t find anything in Marlin, so still don’t think its a firmware problem.

Perhaps this 100 ohm resistor is more necessary and needs to be more accurately sized. Will use a spare thermistor to test and establish it. Needs to be set at 200 deg C, since thats the temp the hot end is required to heat to.

I had the Melzi board spare when I decided that I did not need the Tri color conversion on my RepRap Mendel any longer.

Got to get a spindle on it and start cutting! Using a spring loaded pen to make many lines - Interesting.

At present I still have not managed to overcome the hot end problem, but once the temp is reached the warning siren sounds, and I switch the hot end to off, and repetier makes no further call to the hot end.

The machine is performing well with a pen as a plotter, although I did have trouble with Z axis creep, cured by adjusting G2 and G3 settings in EstlCam. Seems like the Melzi just can’t handle them. Curves are generated as a multitude of tiny lines, which slows the progress down somewhat, and sets up a bit of vibration.

Now for a spindle!

Well the melzi board has a smaller processor that the ramps so that might explain the lack of arc commands.

I can’t find any info about the hot end heating on connect.

Hi all, I finished my mpcnc and it works fine if I use postive coordinates. Negative coordinates are simply ignored, so I am not able i.e. to lower the Z-axis

I loaded the firmware present in this site on my sanguino board (I have a good expertise with 3d printers but NOT with Cnc) and using Repetier.

The machine moves correctly but only if I use Gcode with positive values

Any help will be really appreciated

Thanks all


I’m not sure about the sanguino boards, I loaded this in the firmware. - #define min_software_endstops false (needed to machine in the negative direction)
You don’t need negative coordinates though. You can set the table as your zero and just raise the tool above your work piece.

You using estlcam?

Thanks, the parameter (#define min_software_endstops false) is set correctly.

I use Estlcam but the Gcode generated contains negative values. In example, see the Z command G01 Z-1.0000 F10.000 S24000 hereunder

;Project Soldier outside
;Created by Estlcam version 8 build 8,064
;Machining time about 00.04.24 hours

M03 S24000
G00 X0.0000 Y0.0000 Z0.0000
G00 Z210.0000

;No. 1: Part 1
G00 X74.1044 Y1.1912
G00 Z0.5000
G01 Z-1.0000 F10.000 S24000
G01 X73.5951 Y0.2301 F20.000
G01 X73.5405 Y0.0391
G03 X74.0590 Y-0.5000 I0.4993 J-0.0387

I really don’t know how to solve this matter…any suggestion?

Change these three lines in estlcam.

I have no experience with the sanguino, but the ramps sets handle negatives just fine. Are you using end stops, that would stop negative values from working I think?


No, I don’t use endstops at the present moment.

Now with three lines changed the Z problem is solved, but still I have some negatives in X and Y (see above)

;Project Base
;Created by Estlcam version 8 build 8,100
;Machining time about 00.05.27 hours

M03 S24000
G00 X0.0000 Y0.0000 Z10.0000
G00 Z20.0000

;No. 1: Part 1
G00 X18.9782 Y-0.4745
G00 Z10.5000
G01 Z9.0000 F10.000 S24000
G01 X19.9984 Y-0.5000 F20.000
G01 X180.0016
G01 X181.0218 Y-0.4745
G03 X197.9492 Y10.0974 I-1.0228 J20.4754
G03 X200.4984 Y19.7444 I-17.9434 J9.9019
G01 X200.5000 Y280.0016
G01 X200.4602 Y281.2770
G03 X180.0016 Y300.5000 I-20.4602 J-1.2770
G01 X19.9984
G01 X18.9782 Y300.4745
G03 X1.7576 Y289.3523 I1.0228 J-20.4759
G03 X-0.4984 Y280.2556 I18.2424 J-9.3523
G01 Y19.7444
G01 X-0.4602 Y18.7230

move your pattern a little further from 0,0. That is the bit trying to cut around it.

Sorry, now it’s work perfectly! The zero point was set wrongly!

Really many many thanks for your help!!!

I have no way to test this but I think you really should google the sanguino and figure out why it won’t do negative values. From everything I find it should work.

Reading that link you should really look at upgrading to a ramps board.

Thanks Vicious1, you are really kind! I will buy this:

Is it ok for Mpcnc utilization?

I have always recommended the 8825 drivers. that one will work if that’s what you want.

Thanks Vicious1, I have ordered the RAMPS.

Last question : which software I will need to manage RAMPS? Is it sufficient Estlcam directly connected to Arduino/Ramps?

Repetier-host connects to the arduino, and allows moment and control.
estlcam is for milling, cutting, laser ect- gcode generation.
For 3d printing there is a lot of software out there but I use repetier host for that as well.

Dear Vicious, thanks to your precious help, my Mpcnc based on Sanguino board is working perfectly!

I only got a little problem that I think is depending from the belts not so tight : practically running the gcode two times in sequence (using a pen to see the drawing) the result is a little difference only in a little part of the draw, but always in the same place (see photos)

Do you think that the problem depend from the belts?


If the belts were too loose you would get ringing or skipping and the drawing would look much worse.
I’m not sure what would case that. Is anthing touching the belts when they move? Is the table smooth under that spot? When you mover tha gantry by hand do you feel any binding.

Just an update - I wired the X and Y stepper motors to reversed series connection and whatever else I might have done, have cured the Z axis creep that occurred using G2 and G3 arc codes. Still cannot use Repetier without HotEND connected, Pronterface works for my setup. I am going to fit an LCD screen to the Melzi and run the machine as a standalone, somewhere where the noise of the Makita does not bug me.