Marlin 2.0 - Re-Arm_Ramps does not see Inductive sensor

Hi There,

My old setup i.e. Arduino Mega + Ramps 1.4 + Inductive sensor SN04-N + 24V + Marlin_2.0_bugfix was running fine. No problem printing. It is a hypercube evolution CoreYX printer


I really have a hard time to get my new setup running i.e. Re-Arm 32-bit + Ramps 1.4 + SN04-N + 24V + Marlin _2.0_bugfix. I have upgraded to the 32-bit board and basically just replaced my Arduino with the Re-Arm board. I was lucky and my optical end stops worked with the 3.3V supply. My SN04-N Inductive sensor was putting out 5V when not triggered and 0V when triggered. The digital pins on the Re-Arm is 5V tolerant and this should have worked as is.


Everything else works except that the SN04-N does not trigger the M119 Command.


I then thought I will setup the divider to have a 3,3V rail to trigger the endstop pin i.e. Z_Minimum inverted no pullups or pulldowns, still no triggering.



I then took the sn04 off and enabled pullup resistor on z_min and when I Ground the pin it triggers M119. So the port is not blown.


I am including my config file so that you can see my configuration.


Configuration.h

What am I missing here?

How are you powering the SN04-N? Many sensors that are specified to run off 6-36V will run OK at 5V supply, but will definitely not run correctly at 3.3V supply. You need to power it from a 5V (or 24V) pin on the board. If you power it from 24V you definitely will need a divider network. Be aware that the Re-ARM adds a 10K pullup resistor to each endstop input so that has to be taken into account in your divider network calculations. It might be a better option to use a Schottky diode instead of a divider network, or do what I did and use an optocoupler.

Hi there,

I came right, I used an optocoupler in the end as you did. Works like a Charm. Thanks a lot for answering my question. Now I am fighting an erratic G29 stepper behavior. G28 works perfectly.
Regards

Edited 1 time(s). Last edit at 05/10/2019 07:44AM by scratchbuild52@gmail.com.