I'm just finishing a design for a control board to interface Mach3 to my CNC project.(impression of the pcb design if anyone's interested).
I notice that Mach3 allows for output signals for CW/CCW rotation of spindle and Flood/Mist on the coolant front.
I have implemented three relays and I was idly pondering on how this will go.
I can forsee one spindle relay (CW) and one coolant relay for a mill and two spindle relays (CW/CCW) and one coolant relay for a lathe.
Do mills go backwards?
Now I can't envisage a situation where I would want to program Mach3 to switch between Flood and Mist on the coolant front, so I'm not too worried about only having three relays. I'm thinking that I will set the coolant up before I run the G-code and it will be sufficient to use Mach3 to merely switch it on and off.
The fourth axis could (if not required as an axis) be re-purposed to give a further 3 relay outputs (or indeed speed control of the spindle but I haven't investigated this further).
I would appreciate any comments or observations the group may have.