Z-Probe Woes: G30 Error: Z-Probe Failed.

Hello again, I am running Repetier firmware .93 on a Ramps 1.4 board (the red one) Arduino 2560, Windows 8.1, with a Reprap discount LCD Controller. 

I am working on calibrating my Z-probe, I have the probe wired per Tom's youtube explanation  with a 100k resistor and 150k resistor all of my meter measurements are correct. the power is connected to the Aux 12V pin near the molex connector on the Ramps and the other 2 wires are connected to the Z-Min endstop headers (top two pins of the second to last column if the row of endstop pins is on the top right)  I'll post my firmware settings below if I can

The probe is about 40mm to the right of the extruder. when I run G31 in manual controls the log reads "Z-probe state: H" when the probe light is on and off. if I switch Z-Min inverted to False it will read "Z-Probe state: L" obviously the probe isn't registering, The LED does turn off when I raise the probe high enough over the bed, so the probe seems good. If I run G30 the printer moves to its first position and the log reads "Error: Z-Probe Failed." on my LCD controller the Zmin reads as off. 

Sometimes the G30 command randomly sets my Z height to +- 2000mm if that means anything to anyone. 

thanks for any help 



  • 1. Make sure hardware z-min is false since you are only using the pin.
    2. Make sure z probe pin is set to right z min pin
    3. Maybe play with pullup. With electronics it is normally off.

    The high z values are during probing where it sets target z to 2*z height to make sure it reaches the bottom in any case.
  • 1. Z-min is false (I found that info in another post) [discovered software endstops as well, A+ feature i like it] 
    2. The Z-probe pin is set to #define Z_PROBE_PIN ORIG_Z_MIN_PIN which i would assume is correct for Motherboard 33 as described above.
    3. im not sure what the pullup function does, I can see the sensor turn on and off when i move it away from the bed. so shoudn't the signal change accordingly? 

    thanks again, the High Z values seemed to only be a once every few try problem
  • Also i have only tried the Z-probe hooked up to the 12V with the resistors, its rated at the standard 6V, but does anyone have any experience connecting it directly to the 5V endstop positive pin. I didnt want to burn anything out so i didnt try.
  • Pullup means the processor internally connect 5V over a resistor to the pin, so it is pulled up to 5V level. When you then connect the pin with gnd level shifts to 0 since the gnd connection has less resistance. Without the pullup the signal would be floating.

    Now you have some electronics so the signal pin is probably not floating and pullup may have a bad effect. If you use 12V make sure the signal level  is 5v and near 0V. If low is more then the low treshhold it will always appear as high.
  • Alright so i have it reading high when the probe is off the bed and Low when its close to the bed, i changed the probe pull up like you suggested and still received identical results. disconnected the probe from the Z min pins and recieved identical results except opposite from the plug in tests, telling me that the board was detecting the presence of the probe after the pullup was set to false. so i tried with one pin in slow A plugged in (identical results) one pin in slot B (identical results) and finally switched the pins BAM! low close to the bed High far away. So the probe pullup settings were the problem, as well as the probe polarity. here are my setup settings that seem to work for anyone having an issue. 

    #define ENDSTOP_PULLUP_Z_MIN false
    #define ENDSTOP_Z_MIN_INVERTING false
    #define MIN_HARDWARE_ENDSTOP_Z false

    #define FEATURE_Z_PROBE 1
    #define Z_PROBE_BED_DISTANCE 10
    #define Z_PROBE_PULLUP false
    #define Z_PROBE_ON_HIGH false
    #define Z_PROBE_X_OFFSET 40
    #define Z_PROBE_Y_OFFSET 0
    #define Z_PROBE_SPEED 2
    #define Z_PROBE_XY_SPEED 150
    #define Z_PROBE_HEIGHT 0

    now to test G30 fingers crossed 
  • Bed slam, betcha saw that coming #define Z_PROBE_ON_HIGH false change to false and G32 s0 probes my 3 points five times and seems to work 
  • edited July 2015
    the Gcode probes the bed with G32 S0 runs a single layer, then the entire system locks up no issue with G32 S1 command in the start code. Any ideas., Ive also lost my fan on D9 
  • Glad probing now works.

    Statements like system locks up have no hint on the reason so no idea. Could be communication or firmware or host problem. Needs a context and additional tests liek lcd works, connection lost, commands waiting, log file with ack enabled ...
  • I'm really struggling with setting up the z axis stuff - hope I can find some help here. Apologies if this has been answered elsewhere but sometimes you don't know what you're looking for!

    I have an inductive sensor and RAMPS 1.4 running Repetier Firmware 0.92.4 on a Smartrap Core (core xy). I used Tom Sanladerer's YouTube video to set auto bed levelling with Marlin. In Marlin the same inductive sensor is used as a z_min_endstop as well as the z probe. If I want the same function (something to home z axis and something to enable autolevelling) in Repetier FW do I need to turn off the hardware z endstop and use a software one? The problem at the moment is that I can't get the nozzle close to the bed, even if I change values for:
    I thought that at least one of those would allow me to lower the nozzle a set distance to the bed each time it has sensed when the inductive sensor has triggered (I have confirmed that the inductive sensor triggers correctly with m119)

    My configuration.h is here for anyone kind enough to help http://1drv.ms/1WmHfTG . Please bear in mind that some of those parameters I said I tried changing have been set back to 0 as I try and isolate anything which might make a difference.

    I have no Z max endstop so would still need to define the software endstop based on triggering the inductive sensor attached to the print head.

    I'd be really grateful for any help.

  • You could try negative values for ENDSTOP_Z_BACK_ON_HOME and always check endstops disabled. This is untested since I have no printer to test it.
  • Thanks for the suggestion - I'll try it and let you know. We really need to get you a cartesian printer for the benefit of all us lazy people!
  • I have cartesian printers, only without z probe. But one is coming soon with z probe as well. 

  • Fantastic, is it an inductive sensor? :)
  • No, a switch in the extruder nozzle. So it will get negative z probe height.
  • Ok, thanks. Looking forward to hearing how it goes with this probe. Would you mind posting findings on this thread?
  • I woudn't mind but I will most probably forget it having 400 new questions until then.
  • Ok, I understand how busy you are - will try and remind you with a donation!
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