Inductive Z-probe not seen by Marlin / RAMPS 1.4

Hi,

I just replaced my microswitch Z-min switch (which was just on there for testing and it works) with a "SN04-N 4mm Inductive Proximity Sensor Detection Switch NPN NO DC 10-30V" from ebay. I wired the power to 24V, put in two resistors to split the signal voltage, I have 4.7V unactivated and 0.2V when activated. So I think that part should work.

Next I commented out "#define ENDSTOPPULLUPS" and re-added them for the X and Y axis and kept the inverting setting to false:



But it just doesn't work. Marlin thinks the endstop is not activated, whether it is or not. If I set the inverting setting to true, Marlin believes the endstop is triggered regardless of whether it is or not. I have not been messing with the auto tramming settings, yet, that would be next on the list but I need this to work, first.

Please let me know what next to try, or just point out my mistake!

Cheers,

Hugo

You did not say of not if you have a metal bed, as the proximity sensor will not work without one.

and
#define Z_MIN_ENDSTOP_INVERTING true // set to true for SN-04N False for TL-W3M.
#define Z_MIN_PROBE_ENDSTOP_INVERTING true // set to same logic as "Z_MIN_ENDSTOP_INVERTING".

Edited 1 time(s). Last edit at 09/10/2017 10:44AM by Roberts_Clif.

Thanks. The bed is an 8 mm. slab of tooling plate, the switch sees it and the LED on the switch reacts.

Whether I set the logic to true or false, it doesn't work. I tried both.

In the meantime I think I might have fried the sensor. It only gives very low sens voltages, now. Maybe I used resistors too low in resistance to split the voltage, I used 1K and 220 ohm. The voltage split was nice, but maybe the current was too high. Looking at other set-ups, they all use values about 10 times as high. To me asking 20mA of the sensor doesn't seem excessive, but maybe it was.

Because of that and because I want a glass plate to print on in the future, I just ordered some bits and bobs for a servo / microswitch set-up. The setup already works with a micro switch on a temporary fixed mount to the printer head, I now just need to make the servo retraction.

Cheers,

Hugo

I plugged my SN04-N into the 5v supply line works fine.

Brown wire to 5V
Black wire to NO contact
Blue wire to Ground

Wired like this

I know I got confused because Black is ground but in this case it is NO contact switch. And blue is ground