HICTOP Inductive Sensor Not Working

I have been using my HICTOP for awhile now without issue (other than the normal, sometimes, bed adhesion issue and what not). In my numerous upgrades I decided to include an Inductive Z probe as my endstop. I purchased a LJ18A3-8-Z/BX (8mm sensing distance Orange Tip) from Amazon. I have wired it up, plugging to 12v and the signal to the original Z- endstop signal (or so i think). I have gone through the upgrading firmware process, and before I switch to auto bed leveling I wanted to test to make sure the probe acts as the Z min endstop-however it is not working.

I DO get the light to come on when sensing metalic objects, however it does not trigger the motors to stop. I have the RED MPX-3 board, and there is no markings on this thing which pins, on the endstop connections, are +-S, but i've tried them all with no difference in any case. I've been tinkering with configuration.h and believe i've tried all the combinations i could possibly hit-so now i'm stumped. I'm hoping someone has had a similar experience and can shed some light on what i may be doing wrong. Below is my configuration.h file that I am using right now.


EDIT: Removed pasted configuration-see below comment for bundled firmware i currently use.

Edited 1 time(s). Last edit at 08/07/2016 08:20PM by morris4019.

I have re-checked my wiring. I am getting 4.59v while NOT triggered, 0v while triggered. I have placed the the signal wire on the top pin (of the original 2 wire connection) of the z_min endstop connection. I have tested this also using the other two pins with no change. I currently have the attached firmware. I have followed numerous videos (mainly this one [www.youtube.com] ) as well as many articles-but none have worked. Is there something else that i'm missing to get the inductive sensor to act as the z endstop?

First your part number doesn't work:
NO NPN LJ12A3-4-Z/BX BLUE
NC NPN LJ12A3-4-Z/AX BLUE
NC NPN LJ18A3-8-Z/AX BLUE
NO NPN LJ18A3-8-Z/BX BLUE


NC PNP LJ12A3-4-Z/AY ORANGE
NO PNP LJ12A3-4-Z/BY ORANGE
NC PNP LJ18A3-8-Z/AY ORANGE
NO PNP LJ18A3-8-Z/BY ORANGE
NO+NC PNP LJ18A3-8-Z/CY ORANGE

Post the way you wired the voltage divider, depending on PHP or NPN the wiring is different.

Update on part number: I searched Aliexpress and it is mixed, there is blue and orange along with green now so I have to forget about using tip color to track PHP or NPN.

I broke out the UNO, jumpers, both NPN and PNP sensors, 12 volt supply.
The PHP sensor has 0 volt sitting and 12.47 volt triggered, the NPN sensor has 11.87 volt sitting and 0.685 triggered both are Normally Open BY and BX devices

Using the NO NPN LJ12A3-4-Z/BX Device:
Arduino logic levels are LOW = 1.5 volt and HIGH = 3 volt
TTL Gates in general LOW = 0.8 volt and HIGH = 2 volt
The Triggered voltage of 0.685 volt is below the TTL level and way below the Arduino level
With a voltage divider of 24.4K and 15.5K I should see 4.8 volts to 0.685 triggered
What I do see is 3.7 volts to 0.215 triggered
LJ12A3-4-Z/BX
I tested this with the Arduino DigitalInputPullup example and was able to get measured distance reading from the sensor to a piece of aluminum the same thickness as my bed.
The wiring I used is attached/linked, I think.

Found another post on this forum that reminded me of diodes, voltage blocking diode stops the sensors voltage from reaching the Arduino, one diode with the cathode pointing to the sensor replaced the 24.4K resistor and remove the other resistor.


Edited 4 time(s). Last edit at 08/27/2016 12:02AM by KevinA.

i would try without the diodes the NPN should trigger as a low and pnp as a high level thus a pullup resistor for npn and pulldown pnp and set the true and false on Z axis min for a normally high = open there would be no need for a diode.