Originally Posted by
Raycocnc555
I recently bought a Chinese 4x8 CNC machine that had 12 volt proximity sensors installed. Over the years they had been hacked and were not hooked up. I researched installing 12 volt sensors and understand the need for the resistors. But recently I bought 5 vdc NPN NO proximity sensors, which I thought would make life easy. I connected them to a C25 BOB and get a triggered signal without activating, and then they do not work at all if I switch input settings to active low. I have tried to contact CNC4PC about this since they sell NPN 5vdc proximity sensors, the small square ones, and they said it a very short way, that it was easy to wire them, but did not elaborate. Another question is why aren't the cylinder shaped proximity sensors working on 5 volts used and more common? All I can find on the web is info on using 12 volt ones and having to install a pull down or up resistor to the output lead. Any help on this would be great. How would you wire them to a C25 BOB. Do I still need a resistor?