Ok, so by a master latching relay, how can I mechanize it? I assume your talking about the AC power that powers the motors, spindle, and coolant being physically cut by a relay, when e-stop or fault conditions are detected and staying latched, but how can I achieve this using fault signal - like you say without software?

Neale - the relays on my PDMX perform all the functions of your latching safety relay, except they are not latched ( Unless activated by pressing the latching E-stop switch )