MES 7I96 and NPN probes.

Hello! I bought a bunch of 3 wire NPN probes off EBAY ( these ones) an d I was planning on using them to set all my limits. As far as I understand it (and I'm most likely wrong. The Wiring goes as such...

 

I'm a bit confused with the whole (Pull down Resistor). Do I need it with the 3 wire units? As far as I understand I run power + from my 12V power supply to the Common on the board. BROWN also goes to the 12V+ The BLACK to the INPUT # and the BLUE of the sensor goes to the 12V power supply GROUND.



The manual for the 7I96 states:

ISOLATED INPUT CHARACTERISTICS
For NPN type sensors or switches with a common ground, the input common is
connected to +5 to +36V and the input pins are grounded to activate an input.

The manual says nothing about pull down resistors.  Just don't wanna blow anything up. But from what I'm seeing I don't need a resistor.

I wired up a NPN sensor to a little peice of LED strip and grabbed a milwaukee 12v battery. Low and behold it works 12v on sense. I'm thinking the whole pull down resistor is useful for a 4-20ma type circuit where you care to know that the circuit is alive and health just in a low power state, when it trips it is a high power state. But.... in the case where I'm using it as a simple digital switch and these are 3 wires. it is super cool.

I'm also thinking that this has a pull down resistor in it via the circuit diagram.
 

You don't need any external resistors with 7I96 inputs
as long as all inputs are NPN or PNP type. If you mix input types
you will need external pullup or pulldown resistors.