Hello I’m having a strange issue maybe someone can help me. For Some reason when I go to Home my Z with my touch plate it all works fine touches the plate once then again slowly then after that its supposed to raise the Z up 5mm and then pause to allow me to remove the touch plate. Instead it seems to be going down 5mm into my touch plate. Using EstlCam and the Rambo 1.4 Board. All bought off V1 store and was preflashed ect. (I just got around to assembling my MPCNC 5 years later) Here is my start Gcode. It does do the second line without issues (G00 Z5.0000 F500 ; Raise Z 5mm at 8.3mm/s to clear clamps and screws) so im confused as to why after it successfully probes it lowers instead of raises. I have tried changing that Raise Z probe off surface to Z-5 and that doesnt change anything either.
G92 X0 Y0 Z0 ; Set Current position to 0, all axes
G00 Z5.0000 F500 ; Raise Z 5mm at 8.3mm/s to clear clamps and screws
G28 Z ; Home Z touchplate
G92 Z14 ; Account for probe thickness (set your thickness)
G00 Z5.000 F500 ; Raise Z probe off of surface
M00 ; Pause for LCD button press so you can remove the touchplate
I figured out my issue. As it turns out I need to add the touch plate height to the G00 Z5.000 F500 ; Raise Z probe off of surface So instead of 5 it would be 19 in my case.
it seems your code is running in absolute mode (G90). To raise the tool 5mm after touching the plate with your initial gcode, you need to switch to incremental mode (G91) first.
This isnt correct. That would set it to relative mode and yes it would move the tool up 5mm. But when he started the cut it would be way wrong. Stay in G90 absolute and set the touch plate thickness correctly and all will be good to go as @OhmMyGod has already reported.
Actually after looking at this again, This needs to be set at Z24.000 to move 5mm above the touch plate, if your touch plate is 19mm and you want it to move up 5mm
I agree with @Jonathjon. That said, it WOULD be possible to use G91, as long as you always remembered to switch back to G90 immediately after. The possibility of not remembering, however, is great.
You COULD include the return to G90 in the startup probing gcode, but if you are going to the trouble to edit your starting code, it would be simpler to just set the lift-off thickness correctly (desired travel plus probe thickness) in the first place (IMO).
I agree with both of you. It is just the way I think about stuff like this. In my head I switch to relative for that singe operation and back to absolute, so that I do not have to do calculations when setting up gcode.