Im currently building a cnc mill. I've been looking at proximity switches for the limit switches and I can only find 6v to 36v for a reasonable price on eBay. The controller I am using is a uc300 and only accepts 5v logic.
My question is basically is there an easier and cheaper way to use these instead of buying expensive ones for 5v at about £40 a switch? Or does anyone know of a cheap supplier to the UK?
You don't want to connect your limit switches directly to the motion controller, because it has the risk that the cables picking up noise as they are wired in a noisy environment on a machine frame, moving cable carriers etc.
Industrial sensors mostly using higher voltage levels not TTL 5Volts to have a higher noise rejection and again you don't and can't connect those directly to the motion controller.
Get a breakout board with optocoupler inputs and connect that to the motion controller and then you can connect virtually any voltage signals to the inputs of the breakout board.
You could use mechanical switches and wire 5Volts through them and connect those to the motion controller directly, that would technically work, but again you don't want to do that for the above reason first reason.