@donkjr . I’m installing my grbl controller and would like to replace the upper left (Y-AXIS) Optocoupler with a NC limit switch in the bottom left so that I don’t have to invert the image due to inability of inkscape to give an origin at upper left.
I think I can remove the resistor that effectively would protect and disable the Y-opto, and then wire the NC limit switch to pins 7 and 9 of C10. Can you please confirm.
Of course, I’m referring to “the middleman” schematics on your site.