Error:Z-probe failed

furynick

Hello, I think there's a problem when Z-probe is defined on same pin than min Z end-stop.
I have Z-probe failed error from time to time when nozzle hit bed without any clue on what happened and I can't achieve Bed Height map creation. The Z motors wires are far from endstop wires, I doubt it can be caused by EMF.

Hardware used : RAMPS 1.4 on Mega2560, cartesian printer, optical endstop with electronic pullup (10k to Vcc), pullup diabled on both Z-probe and end stop in Configuration.h.
Firmware : 0.92.3

I guess the endstop code occur just before Z-probe one and conduct to a missed step so stepsRemainingAtZHit remains negative. Perhaps endstop detection could be disabled when unsing Z-probe commands.

Feel free to ask me any other details.

Regards,
Nicolas.

UniversalRemonster

I am having a similar Z-Stop issue with firmware 0.92.4 and 0.92.5. Delta Configuration. Mechanical normally closed z-probe on effector. Verified working with ohm meter. Bed leveling works with RC Marlin.

The issue is my Z-Probe always reports back High with an M119. Doesn't matter which pin location I move the endstop too, even unplugged.

Here are some configuration settings that I think may be relevant:

Enable Z-Correction: Yes

Store Correction Data in eeprom: Yes

Always Check Endstops: Yes (confident in no cross talk)

X Min Endstop: Not Installed, Pin: Disabled

Y Min Endstop: Not Installed, Pin: Disabled

Z Min Endstop: Not Installed, Pin: Disabled

X Max Endstop: Yes, Pin: X Max Endstop

Y Max Endstop: Yes, Pin: Y Max Endstop

Z Max Endstop: Yes, Pin: Z Max Endstop

Enable Z-Probing: Yes

Enable Automatic Bed Leveling: Yes

Enable Pullup Resistor for probe pin: Not checked

Z Probe Pin: Z min endstop

I kind of think it's a bug, since everything works in Marlin and it all Ohms out working. M119 is useful, but never sees a low state Z-Probe, no matter what.

UniversalRemonster

I figured it out.

in Configuration.h #define Z_PROBE_PULLUP is set to 0 by default, which is disabled. I switched it to 1 and my state now toggles correctly with M119.

This is tied to the "Enable pullup resistor for probe pin (Z_PROBE_PULLUP)", which needs to be checked.