Negative Coordinate Machine Setup

grbl

(Rick James) #1

Negative Coordinate Machines

If your machine uses negative coordinate space, we need to offset the origin.

LightBurn wants positive workspace numbers, like this:

This image shows the origin at the front-left, with positive X values moving to the right, and positive Y values heading to the rear of the machine.

A negative workspace system looks like this:

In this image, the origin is at the rear-right of the machine. The X and Y directions are the same as before, but now, to move into the work area, you would need to use negative numbers. Instead, we’re going to set up a work offset.

You’ll need to know the total distance your machine can travel in both axis. For a Shapeoko XXL, for example, it’s 812mm in X and Y. For a 500x500 X-Carve, it’s 250mm in X and Y. By applying a workspace offset that is the size of your machine area, we can shift the offset to the opposite corner, like this:

Enter the following command:

​ G10 L2 P1 X-250 Y-250

in the console, and hit enter. Note that the ‘250’ above should be replaced with the total travel width and height of your machine. If your machine had a 600mm width and 400mm height, you would use:

​ G10 L2 P1 X-600 Y-400

This command offsets the origin by the given amounts. If the origin used to be in the rear-right of the machine, and you offset it in the negative direction by the width and height of the work area, you’ve moved the origin to the front-left.

If you enable a workspace offset, you will also need to make GRBL report its location relative to this shifted origin, instead of in “machine space” by setting $10=0. Some systems, like Easel or Carbide Motion, may need a different value, so it is good to remember the existing setting.


Shapeoko - XXL Can't set negative coordinates
(Rick James) closed #2

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