PNP proximity sensors as home switches?

[DanielCA92563]

Hello,
I'm tackling my switch over to acorn today.
I currently have PNP proximity switches on X-,X+, Y-,Y+, and Z+ as home/limit switches for my G0704/Hicon motion controller. 24 volts is put across the blue-brown wires of my 3 wire sensor. when the switch is activated, the third (black wire) sends a 24 volt signal. How can I connect this set up to the Acorn board? Any help is appreciated.
- Daniel

[frijoli]

I don't believe that will work without a relay. If I am reading the Acorn schematic correctly the limit switches use the negative side of the power to activate. Meaning the switches are "on" when they are shorted to COM.
You would want to use an NPN sensor in this case.

You could add a relay to reverse the polarity. There is a way to do it with resistors, but I wouldn't recommend it in the case of the Acorn.

Some of the Acorn gurus may have a differing opinion, but I would get new sensors.

Clay

[DanielCA92563]

Clay, thank you for your help.

I was hoping not to have to replace the sensors but it was quick and painless. NPN sensors worked great.
Thanks again.

[frijoli]

Clay, thank you for your help.

I was hoping not to have to replace the sensors but it was quick and painless. NPN sensors worked great.
Thanks again.

Awesome! Glad it worked out. What are you working on?

[martyscncgarage]

Clay, thank you for your help.

I was hoping not to have to replace the sensors but it was quick and painless. NPN sensors worked great.
Thanks again.

Glad you pointed that out, need NPN relay boards on the outputs a well. There are two built on to Acorn but I expect many users will want more.
The ebay relay boards are attractive because the are small, but be sure to look for NPN type. Acorn grounds the output. If you have a single relay it doesn't matter.