Zeroing a non - end stop MPCMC

Mostly Printed CNC - MPCNC Advice
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Hardware is standard MPCNC, 2’ x 2’. Controller is MKS Gen L v1. 0 with RepRap Discount Full Graphics Display. Firmware is download standard for RAMPS 1.4, no dual end stops. Only change necessary was the correct board name

Manual control from RepRap smart controller works.

Manual control from Repetier works

Have not tried SD card.

Crown gcode runs successfully from Repetier

My question is about the optimal zeroing/homing procedure for using Repetier

From reading the forum it appears that the home position for this setup is arbitrary. However it’s not clear how to set the home position in Repetier, aside from resetting the firmware with the button on the smart controller. Is it possible?

Right now, the process that I have determined to work is

  1. Move the gantry to the desired home position using either Repetier in manual mode or using the RepRap smart controller. (or, manually if all power is off)

  2. Reset the firmware by pushing reset button This sets the coordinates of the present location in Repetier to (0,0,0). Probably could reset by other means as well?

  3. It appears that Repetier will retain this value for “home” until there is another reset or power cycle, correct? Is it possible to set “home” in some other way?

One thing that is not clear is what the various “home” buttons in Repetier and on the smart controller are supposed to do. In particular, pressing the “Home X” (or, Y, or Z) on the controller results in an error saying that “homing failed” but I don’t know what is supposed happen instead.

So, is there another method to set “home”? Or is resetting Marlin the only way for this setup?

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You don’t really need to. When you start it it assumes it is at home.

 

If you are having some sort of issue you can use G92 X0 Y0Zo as the first line in your gcode to set it all to zero (I do this).

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I move my gantry against a set of emt hangers while it’s off so I know it’s square and have added the g92 line to Estlcam so I don’t have to do anything except move to wherever I want to start before running gcode.

4

A lot of us have also set one of the macro buttons to send the G92 command. I have one of the others send G92 Z0 so I can just rezero Z by itself. This keep you from having to power cycle the machine, potentially causing the Z to drop.

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This is interesting. If I understand correctly, this would also be useful after a tool change to establish the new zero for Z without changing X and Y. Right? I have not tried to do this, but is it possible to send a gcode command while the machine is paused (e.g. in Repetier)?

Understand that while I have everything running, I have not yet done anything beside draw because I need to fabricate a tool mount. However, I have been able to control through Repetier, including running the crown image, as well as from the SD card (RepRap smart controller). I see a button to pause the “print”. Is this how one does tool changes? (I do NOT have dual end stops at this time.)

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Yes, you can manually send gcode while it is paused. If you search the forum for tool change, there are a couple of threads. SomeOldGuyCoding made a youtube video of how he does tool changes without endstops.

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