Hi all,

I've got my CNC setup with a 48v PSU powering he controller board with steppers and a 12v PSU powering my 3 proximity sensors (NPN Inductive). What I'm doing at the moment (which is working) is connecting all the + and - leads of the sensors together with the + and - of the 12v power supply respectively. I then plug the output line from NPN sensor to the breakout board (Gecko 540). I was then told I had to connect the ground of the 12v to the ground of the 48v PSU. That's all working fine but having two power supplies hooked up like that is bothering me.

I had 3 other ides which I'm not quite sure how to implement:

1.) Connect the 3 sensors in series. Not their output lines... just the power lines. If I understand that correctly, 3 sensors (rates at 10v-30v) connected in series with 48v supplies should supply 16v to each sensor. Will that work? It would eliminate the 12V PSU which would be advantageous.

2.) Remove the 12V power supply and buy/create a circuit that steps the 48V down to something in the 30v-10v range. I would keep the common wiring as is and just connect the + lead from all sensors to this circuit. I've got a bunch of small time components on me, I think most of the voltage regulators are 12v/5v but I have plenty of resistors, capacitors and diodes that I hope I can whip something up with. I'm not quite sure how to do that though.

3.) Buy a relay for each sensor. This option is the most confusing for me. I have a 12VDC relay lying around with 4 pins. It doesn't have a second voltage on it like some of the others I've seen so I'm guessing it takes 12VCD as input and can only switch 12VDC. I'm guessing I need something that takes 12VDC and switches on 48VDC? This is the option I'm most sketchy on.


I'm really hoping option one works but I don't want to try it in case I blow something up. Which do you think is a good option?


Thanks.