Problem Issue with geo correction


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    Default Issue with geo correction

    Hi, Tom

    I decided to use the geo correction to improve the flatness and encountered a problem in measuring the length when changing the tool. When changing a tool, I use the MoveAtVel function in machine coordinates. Depending on the initial position on the table, I get a different length of the tool. Looks like lost geo correction offset. How can I get geo correction offset from code?

    Updated to version 4.34j, nothing changed.

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    Default Re: Issue with geo correction

    I tried to move spindle in the same position before tool change with MDI command, it works from KMotion, but dont work from KMotionCNC, nothing happening on MDI command!



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    Default Re: Issue with geo correction

    Since we are on different sides of the planet, just in case, I will clarify.

    When using Move commands, correction does not occur and the coordinate is lost. If I could get the geo correction Z offset from the code, I would bypass this problem.

    Second. I tried to use MDI command like MDI("G0 Z100") to move spindle to the same position before Move commands. All works from KMotion C-code editor, but when I call this same file from KMotionCNC M-code nothing happened.



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    Default Re: Issue with geo correction

    Addition - MDI does not work only in exec/wait and exec/wait/sync modes, it works in the "execute prog" mode, but such use is not possible.



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    Default Re: Issue with geo correction

    Hi mk00,

    Sorry I'm very confused. But yes with Geo Correction the KFLOP raw Coordinates will be a distorted transformation of the GCode CAD Coordinates.

    It isn't clear to me how you are measuring the tool.

    KFLOP MDI commands can't be used from an M Code called from GCode (The Interpreter is not re-entrant).

    There is a function to return the currently commanded position in Geo Corrected CAD Space. I would think that might work for you.

    Regards


    Code:
    int GetMachine(double *Machinex, double *Machiney, double *Machinez, double *Machinea, double *Machineb, double *Machinec)
    {
    	if (DoPCInt(PC_COMM_GET_MACHINE_COORDS,TMP)) return 1;       // Var index and Cmd
    	*Machinex=GetUserDataDouble(TMP);
    	*Machiney=GetUserDataDouble(TMP+1);
    	*Machinez=GetUserDataDouble(TMP+2);
    	*Machinea=GetUserDataDouble(TMP+3);
    	*Machineb=GetUserDataDouble(TMP+4);
    	*Machinec=GetUserDataDouble(TMP+5);
    }


    TK
    http://dynomotion.com


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    Default Re: Issue with geo correction

    I measure tool length after each change. The spindle moves down at MoveAtVel command to the measurement device until the contact closes.
    I would like to get the geo offset directly as OriginOffset and AxisOffset.
    Machine = DRO + OriginOffset + AxisOffset + ToolOffset all this I can get but where the Geo Correction offset?



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    Default Re: Issue with geo correction

    Like I solved the problem. When measuring the length of the tool, sometimes the geo offset turned out to be different, although the measurement always occurs at one point. I was not able to find out in what situations this is happening, like this is due to the launch of the G-code program, possibly with its stop (Feed hold then Stop).

    I subtract the geo offset at the measurement point from the length of the tool and now I always get the same tool length. I got geo offset as MashineZ-Ch2->Dest/Steps_per_mm



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    Gold Member TomKerekes's Avatar
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    Default Re: Issue with geo correction

    Hi mk00,

    Thanks for taking the time to post back.

    If I understand correctly, you are correct in that wherever the Job ends (in XY) will alter the actual Z position in raw KFLOP Z counts, depending on the Geocorrection at that location.

    Your formula compares the last commanded height in CAD Space with what should be the height in CAD space if there was no correction.

    Regards

    TK
    http://dynomotion.com


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    Default Re: Issue with geo correction

    At first I thought that when moving around the axes with the Move command, the Z geo correction is lost, but this is not the case - Z changes accordingly when moving. The assumption that the length of the tool depends on the initial position on the table was not true. But sometimes something happened and I get different geo offsets at measurement point. I checked the offset in the center of the table - it's always the same. When I call the tool change manually through the drop-down menu or command like M06 T02 G43 H02 this does not happen.



  10. #10
    Gold Member TomKerekes's Avatar
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    Default Re: Issue with geo correction

    Hi mk00,

    At first I thought that when moving around the axes with the Move command, the Z geo correction is lost, but this is not the case - Z changes accordingly when moving
    I don't think that is the case. The Geocorrection is performed in the PC. When you move XY in raw KFLOP coordinates the Z axis will not move. However the reported Z position in the DRO's (CAD Space) will change to reflect the true Z Position in CAD Space.

    Its not clear to me all the steps you are performing.

    Regards

    TK
    http://dynomotion.com


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