This config is a simulated stepper machine with the addition of
ClassicLadder connections to some of the LinuxCNC IO.  The initial ladder
program includes several possible estop arrangements and a timed lube
coil.  The lube ladder includes a sense run that watches lube level or
lube pressure and warns of a lube condition failure.

This ladder integration with the HAL will allow you to expand the IO
interface to a minimill with spindle and tool changer controls.

