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### Author Topic: A simple G question. How to move to x=4,y=0 when current position is random  (Read 3326 times)

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#### DavidCousins

• 60
##### A simple G question. How to move to x=4,y=0 when current position is random
« on: October 19, 2007, 03:28:27 PM »
I have a move question.

Situation: I'm working a job and my spindle XY is in random space.   I want to type in a manual G command to take my spindle to x=4 y=0 (in the job coordinates).  Just a single command is my desire.   I know the G0x4 is a relative move.  My desire is to find the absolute x=4.

Is there a G command for such an move?

Thanks,
Dave

#### zarzul

• 239
• Wyoming, USA
##### Re: A simple G question. How to move to x=4,y=0 when current position is random
« Reply #1 on: October 19, 2007, 03:42:44 PM »
Dave,

g90 puts you in the absolute mode
g91 puts you in the incremental mode

so g0 x4 can be incremental or absolute depending which mode you are in.

g90
g0 x4 y0
will put you at the absolute position of x4 y0

Arnie

#### DavidCousins

• 60
##### Re: A simple G question. How to move to x=4,y=0 when current position is random
« Reply #2 on: October 19, 2007, 05:30:06 PM »
Arnie,

Next question.
What are the consequences of turning on g90 and forgetting to return it with the g91.     I guess it depends on my CAM post processor.

If the post processor didn't begin the file with a g91, I'd have a mess.  correct?
Dave

#### zarzul

• 239
• Wyoming, USA
##### Re: A simple G question. How to move to x=4,y=0 when current position is random
« Reply #3 on: October 19, 2007, 05:37:04 PM »
It could get ugly indeed.

For the most part, in my limited experience, most moves are done in an absolute mode.  The incremental mode is used mostly in subroutines (not sure if thats what they are called)
where you are machining multiple identical parts out of one piece,  the main program takes you to a start point or offset and then you go into a subroutine that uses the incremetal mode and machines out the part, then returns you to the main program in the absolute mode moves you to the next point and loops back to the subroutine to do it all over again.

#### vmax549

##### Re: A simple G question. How to move to x=4,y=0 when current position is random
« Reply #4 on: October 19, 2007, 08:20:42 PM »
G0 x4y0   works for me (;-) TP

#### DavidCousins

• 60
##### Re: A simple G question. How to move to x=4,y=0 when current position is random
« Reply #5 on: October 19, 2007, 08:43:47 PM »
I just reviewed two of my VcarvePro g code files.   Both files had a G90 in the header, but they didn't have a G91 anywhere.   So now I'm confused as to why when I use the G0x4y0, I get an incremental (relative) movement.   I see that Vmax gets an absolute.

I wonder what triggers Mach3 to return to incremental mode for my case.  When I'm done with cutting file, and I use g0x4, it's always relative.

I appreciate you guys responding.
Dave

#### vmax549

##### Re: A simple G question. How to move to x=4,y=0 when current position is random
« Reply #6 on: October 19, 2007, 11:03:13 PM »
CHeck your config page to see if it is set to incremental instead of absolute. Some programs have a bad habit of NOT leaving mach in the condition it found it in (;-)

YOu can set up an initialization string to run on all resets if needed.

(;-) TP
« Last Edit: October 19, 2007, 11:08:31 PM by vmax549 »