Going a bit forward in my Denford Triac conversion to mach3, I've begun to map the different sensors and switches.
As you may know I got the machine already taken apart with all the electronics in one box.
Nevermind that as I'm going to run it of a CSMIO/IP-S which should be in the mail next week or so

I've come upon the min/max switches and the reference inductive sensors.
I know of NPN/PNP type three wire sensors, but these are only two wire.
From what I can gather they are ohmic, meaning that contact induces high resistance.
Does that mean that they are not semi-conductive and does anyone know what voltage I can safely operate them on?
Regards,
Jens