Keeping zero position

[Festdewalkita]

@Aiph5u

Buildbotics is not based on LinuxCNC, as Buildbotics is the own work of its creator, but its g-code syntax is patterned after the LinuxCNC g-code syntax

Tomatoe/tomato. The distinction might be pedantically pure, but it doesn’t do much to add to the conversation.

@Aiph5u

G2 (Clockwise Arc Move) is identical to G02

As I suspected. So

@dtbiz

G02 X0 Y0
Copy G01 line and paste in the MDI window, click the run arrow.
Copy the G02 line and paste, click the run arrow. This sets the offsets. Alternate click the X set and Y set buttons (not the home buttons).

makes no sense to me.

@Aiph5u

The numbered parameters #5161 – #5169 store the machine coordinates of the home position for the axes X, Y, Z, A, B, C, U, V & W, therefore after homing, G28 moves to machine origin (aka ‘home’)

G28.1 sets these parameters to the values of the current position, but the position is in absolute machine coordinates.

You can check the values at any time with the g-code command:

M0 (debug, G28 settings: X=#5161, Y=#5162, Z=#5163)

I don’t know if you rather are interested in the G52 and G92 commands. After probing your workpiece in XYZ, the G92 command sets the new workpiece zero as the X,Y,Z zero position of the workpiece coordinate system. Any subsequent G0, G1, G2 and G3 motion commands will then take the workpiece zero as coordinate system zero. E.g. G0 X0 Y0 Z0 will then move to the workpiece zero. You can still move to machine zero (‘home’) with G53 G0 X0 Y0 Z0 when a workpiece coordinate system is in effect.

This is the confirmation I was seeking. It seems to me that getting the gantries really close to snug (rather than letting the 1F BB do its stall thing) is much more likely to result in a larger machine working area, and should be a more reliable machine zero to boot.