Homing and touch-off are not at all the the same thing. It sounds like you are using the machine coordinate system (homing) as your work coordinate system (touch-off). This works but it it isn't very flexible. When I start my linuxcnc milling machine, I run the homing routine to establish the machine boundaries. This prevents the machine from crashing into its own end-stops regardless of what the gcode says.herbk wrote:Hi sliptonic,
in that time path WB produces gcode with a G00 X-1.0 Y1.0 comand in the postamble.
If i not change the X-1.0 to 0 (or higher), linuxcnc gives me a warning about a path over the limits.
You are right, i can ignore that. But if i do so, and have a machine setup like mine, where the mechanical limit is realy close to the softlimit i run in problems.
My machine (a router) works like that:
I switch it on and make a calibration run. This run sets the 0 pionts for X, Y, Z by runing on the limit switches. The way from touching the limit switch to the mechanicel "touch" is 1mm.
After changing the tool ( on my own machine i have to do manuell) i run the Z axis down to the table to set the touch off and back to 0.
The sheet of material is always placed on X0, Y0. So it's easy to place a new sheet of material and after changing the tool i have only to adjust the touchoff new.
Around me the most people working with router setups like this
Then I touch-off to establish o the X=0 Y=0 coordinates for the work piece. In linuxcnc, this has the effect of moving the gcode plot within the machine boundaries. When this is done correctly, negative XYZ coordinates won't give any warning at all.