Hi,
the cheap USB external controllers supplied typically have the equivalent of 'one ports' worth of IO,
that is the same number of inputs and outputs as Machs parallel port......12 outputs and 5 inputs.
You are pretty much required to have one input as an Estop. that leaves just four inputs for limit switches,
home switches and a probe. As you can see inputs are at a premium.
Over the years many people have used different wiring schemes to combine as many limit and home switches together
to conserve inputs.
You will have to identify the inputs on your board and use those. Support and documentation for those cheap USB
boards is atrocious. Good luck.
I bought an Ethernet SmoothStepper (ESS) and it has 'three ports' worth of IO, 51 inputs and outputs....plenty!
It means I don't have to combine limit and home switches. My current setup has three home switches (x,y,z), each
on there own input and all six limit switches wired in series on another input and one input for a probe.
I could, and in fact should, have all six limit switches on individual inputs, it lessens confusion and improves
the safety and security when recovering from a limit event. The ESS has plenty of spare inputs so why not use them?
Craig