I am making my first foray into CNC machining with an old Amdek plotter and running GRBL on an Arduino Uno. So far everything works great and I can plot perfectly! The last bug is getting the plotter to go through the homing cycle. If I click the "Home Machine" on the Universal GCode sender, the plotter barely blips and just sits there. I suspect it is looking for the Z limit switch which I don't have and don't need. (I do a raise and lower pen with a solenoid). I have run the setup wizard and it does recognize the +/- X and +/- Y switches. Should I just put a jumper across the +/-Z pins on the control board (protoneer CNC shield) to fool GRBL? My switches are wired Normally Open.
What you need to do is read the GRBL wiki which tells you how to do this. You have to recompile GRBL to tell it to ignore Z homing, jumpering will just cause trouble and will not work. gnea/grbl So you need to read the config.h file carefully and make changes to ignore Z homing. instructions for 2 axis homing are in this page gnea/grbl
