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How to go to a negative Z
Posted: Wed Apr 27, 2016 4:29 pm
by Johncoffee
In order to do some calibration stuff, I'd like to move the nozzle to a negative Z value. (e.g. when at 0 the head is for example still 1mm above the bed). It seems that I can't move the head lower - the command is simply not executed (G1 Z-0.1 or clicking Z- on the controls). The Z position value however decreases - but the head doesn't move.
I've selected "Allow negative Z" in the Printer settings in MAttercontrol to no avail.
Any help how I can do this?
Thanks - *John*
Re: How to go to a negative Z
Posted: Wed Apr 27, 2016 5:01 pm
by Eaglezsoar
Replying to refresh, can any forum user help Johncoffee with the problem he is having?
Re: How to go to a negative Z
Posted: Wed Apr 27, 2016 6:02 pm
by Nylocke
The Mattercontrol setting likely doesnt do anything. I'd recommend using the LCD interface (set z 0 in config menu)
Re: How to go to a negative Z
Posted: Thu Apr 28, 2016 1:30 am
by Johncoffee
Thanks Eaglezsoar for bumping!:-)
It's not Mattercontrol that doesn't do anything as I can see the command G1 Z-0.1 being sent on Terminal. The Rostock Max V2 or most probably Repetier prevent me from doing this via a Terminal command. Of course the knob would be possible but via the buttons on Mattercontrol / Terminal command would be beneficial. Is there any way of bypassing the limits?
Re: How to go to a negative Z
Posted: Thu Apr 28, 2016 7:05 am
by Johncoffee
It appears that a negative Z probing had been already discussed in 2014 in this forum :
http://forum.seemecnc.com/viewtopic.php?f=57&t=4667
Even there are other suggestion to calibrate with the screws, I think that using the Rostock Max V2 internal Z measuring can be helpful to calibrate it -instead using a additional depth sensor for example. I negative Z-heights would be allow, the calibration can be done without changing the end screw positions at the towers.
By using commands like shown here would be interesting:
https://www.youtube.com/watch?v=tDLbqLve128
Re: How to go to a negative Z
Posted: Thu Apr 28, 2016 9:34 am
by geneb
The firmware won't permit negative Z moves.
g.
Re: How to go to a negative Z
Posted: Thu Apr 28, 2016 3:39 pm
by Johncoffee
...but interestingly it does when using the knob at the front panel...
Re: How to go to a negative Z
Posted: Thu Apr 28, 2016 3:46 pm
by Nylocke
Thats a special feature. Its an illegal move except in a firmware implemented exception.
Re: How to go to a negative Z
Posted: Thu Apr 28, 2016 5:34 pm
by Johncoffee
my firmware is original - no mods made.
Anyway - I think need to find a another way without negative Z playing around
Re: How to go to a negative Z
Posted: Thu Apr 28, 2016 5:49 pm
by Nylocke
No, as in Repetier has that feature implemented through the LCD. Its a stock feature. It can't be accessed outside of that menu.
Re: How to go to a negative Z
Posted: Fri Apr 29, 2016 8:46 am
by geneb
It's designed specifically to allow you to set the Z-zero point from the LCD.
g.